nsw home solar battery guide

NSW Home SolarBattery Guide2020

ForewordThe Hon. Matt Kean MPMinister for Energy and Environment

I’m pleased to release this updated NSWHome Solar Battery Guide, an importanttool that helps our NSW ElectricityStrategy to deliver better outcomesfor energy consumers.

Rooftop solar panels are more affordable thanever and the people of NSW are capitalisingon this clean energy opportunity. Around500,000 households are already harnessingthe power of the sun.

Battery storage allows people to bank theirsolar supply and use it any time—day ornight. While batteries may not be suitable foreveryone, people with rooftop solar shouldconsider whether storage works for them.

The Australian Energy Market Operatoranticipates more than 1,000 megawatts ofbatteries will be installed in NSW by 2035.This is partly due to progress in batteryefficiency and affordability.

This guide seeks to help consumers answer

two questions:

• Will battery storage save me money?

• How do I choose the right battery system?

The guide provides general advice and everycare has been taken to provide accurate andup to date information about the rapidlyevolving battery market. You should seekexpert advice to decide what option is rightfor you.

NSW has an objective of net zero greenhousegas emissions by 2050 and the actions ofindividual households and consumers will becrucial to helping meet this target. The NSWgovernment aims to accelerate the transitionto emerging clean energy sources. Part of thatis empowering you to access clean energy inthe best ways possible. This NSW Home SolarBattery Guide shows you how.

NSW Home Solar Battery Guide2

3NSW Home Solar Battery Guide

NSW Home Solar Battery Guide

ContributorsThe NSW Home Solar Battery Guide was originally published in 2017 with advice from the TotalEnvironment Centre, in collaboration with then Alternative Technology Association (now Renew)and Zumio. This updated edition was developed with advice from ITP Renewables in consultationwith industry stakeholders. The Department appreciates the valuable input provided by industryand other stakeholders in the development of this guide.

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Contents1 Your Home Solar Battery Guide 6

The changing energy market 7

What this guide covers 8

Who is this guide for? 9

How to use this guide 10

2 Understanding your energy use 12Household energy use 13

Find and understand your energy information 16

Easy things to do first 18

3 Your home power station 20How a home power station works 21

Battery basics 24

How green is that battery? 30

4 Planning for a battery 32Options for adding a battery 33

Battery sizing 34

Future proofing 38

5 Will a battery save me money? 40Calculating the payback period 41

Typical payback periods in 2020 42

Are batteries a good investment right now? 44

6 Buying a solar battery 46Getting a quote 47

Choosing an installer 48

Options for buying 50

Connecting to the grid 51

7 Owning a battery 52Managing your battery 53

Monitoring and maintenance 55

Safety 56

8 Additional information 58Frequently asked questions 59

Glossary 61

Where to go for more help 64

Modelling assumptions 68

Notes and references 70

Your home solarbattery guideThe changing energy market 7

What this guide covers 8

Who is this guide for? 9

How to use this guide 10

Section 1

6

The changing energy marketAustralia’s energy system is going through a transformation. More than 500,000 householdsin NSW have already installed rooftop solar systems, with many more expected to follow incoming years.

Home solar battery systems can storesolar energy generated during the day andmake it available when the sun isn’tshining—potentially saving the householdmoney. They deliver a clean, secure andreliable energy supply.

Battery storage systems for households arenot new. For decades people have used themto support their use of the grid or to operateoffgrid if they are in remote locations. Thesesystems mainly relied on lead acid batteries.They were individually designed and ofteninvolved significant installation time and cost.

Increased demand and improvements inbattery storage technologies, includinglithium-ion, mean that today’s systems canstore much greater amounts of energy in

a smaller volume and have an increasedlifespan. While lithium-ion batteries are themarket leading technology, there are othertypes available, and there are even variantswithin the lithium-ion family. Most importantly,their cost is rapidly reducing, making themmore financially viable.

Home solar batteries are also an importantlink in the transformation of the grid. Theold centralised model featuring the one-way flow of electricity from big generatorsto consumers is changing into a new modelfeaturing two-way flows between ‘prosumers’(producer-consumers) and the grid (seeFigure 1 below). They can help reduce theneed for expensive peaking generators whenelectricity demand is high.

Figure 1. The changing energy market1

In the old system energyflowed in one direction.

Recent Past Into the future

Energy flows in two directions, and thecustomer is at the centre of the energy flow.


Section 1

What this guide coversBattery storage systems are a substantial investment, so it is important to understand whatvalue they provide and if you would benefit from one. Keep in mind that there are alternativeoptions available to save energy and money. This guide will help you understand the belowpoints when considering a home solar battery.

In many NSW locations and households a new solar battery system can pay for itself withinthe typical 10-year warranty period. However, most of these savings will usually come fromthe solar PV rather than the battery. Batteries are expected to provide greater value as batterycosts reduce and tariffs change. Also they provide opportunities for households to generateadditional revenue from their system through energy services such as virtual power plants.

Is getting a battery a good idea?

• Your motivations for considering a batterywill help establish whether you wouldbenefit from one.

• Understanding how and when yourhousehold uses electricity will help youdecide whether a battery is right for you.

• There are a range of alternativesavailable to you, and depending on yourcircumstances, they may offer better valuefor money than a battery.

When do batteries makefinancial sense?

Individual circumstances, such as howmuch electricity you use in your home andwhen you use it, will determine whethera battery makes financial sense for you.Accredited suppliers can help you make thisfinancial assessment.

• In most NSW locations and householdtypes, a new solar battery system isexpected to pay for itself within the typical10 year warranty period.

• In most situations, retrofitted batterieswill not yet pay for themselves within 10years, but this may change as battery costsreduce, tariffs change and other benefitsdevelop such as virtual power plants.

• Batteries can also have practical, non-financial benefits such as powering yourhome in a power outage or supporting thegrid by exporting energy at peak times.

• Going offgrid only makes financial sense ina few select circumstances.

What are the critical things you needto know when buying a battery?

• Quality—choose a quality product and anaccessible and licensed installer with agood reputation.

• Size—choosing an appropriately sizedbattery for your needs is critical to get thebest economic return. The payback forsmaller batteries, when purchased with anew solar system, is typically shorter thanfor large batteries (see page 34).

• Software—the energy management systemis key to making the whole system work(see page 22).


Who is this guide for?The NSW Home Solar Battery Guide helps households make informed decisions whenconsidering buying and owning a battery system.

The guide will explore a range oftopics including:

• installing new rooftop solar togetherwith a battery

• adding a battery to an existing rooftopsolar system

• installing a battery without solar

• using a battery to disconnect from the grid.

This guide is designed for home owners,and is not intended for business owners ortenants. It outlines things you may wish to

consider when making financial decisions.However, the guide does not providefinancial advice.

The guide does not cover going offgrid indetail because in most cases this is not afinancially viable option.

The technical information and financialanalysis in the guide are based on extensivemodelling undertaken by ITP Renewables,using current information as at January 2020.

Extra resourcesThe NSW Home Solar Battery Guide page on the Energy Saver websiteprovides extra resources, fact sheets and practical examples to furthersupport the information in this guide.

energysaver.nsw.gov.au/solar-battery-systems


Section 1

http://energysaver.nsw.gov.au/solar-battery-systems

How to use this guideWhether battery storage is right for you, and which kind, depends on what you want it toachieve. Your motivations will also affect how you navigate this guide and supporting materialon the website. Refer to the below motivations and practical examples relevant to you whenconsidering a home solar battery system.

‘ I want to save moneyby reducing the amountof power I import from

the grid.’With energy bills having

risen significantly inrecent years, it makessense to look at ways

to reduce costs. While abattery may reduce your

bills, it does not mean thatit will pay for itself within

the warranty period.

Understanding yourenergy use (page 12)

Easy things to do first(page 18)

Planning for a battery(page 32)

Will a battery save memoney? (page 40)

‘ I am concernedabout climate changeand want to supportrenewable energy.’Any solar energy yougenerate will reduceemissions from fossilfuelled generation,whether you use it

yourself or export itto the grid. Addinga battery may notnecessarily furtherreduce emissions.

Easy things todo first (page 18)

How green is thatbattery (page 30)

‘ I want to have morecontrol over mypower supply.’

Many people wantto buy a battery asinsurance against

potential future energyprice rises. You may

also wish to rely less onyour electricity retailer

or network.

Easy things todo first (page 18)


Should I go offgrid?(page 36)

Guide focus areas

Guide focus areas

Guide focus areas

Cutenergy bills

Become moreself-sufficient

Accessrenewable energy


‘ I want to sell energyback to the grid.’

With a battery you maybe able to earn moneyby exporting energy

to the grid duringpeak periods.


Managing your battery(page 53)

‘ I want backuppower in case ofpower outages.’Most parts of the

network in NSW havebeen very reliable overa long period. Not allbatteries can operateindependently if thenetwork goes down.

Battery sizing(page 34)


Should I go offgrid?(page 36)

‘ I just want one!’As an early adopter ora tech enthusiast, we

recommend researchinga range of topics

from battery basics todesigning and buying

your home solar batteryso you’re informed

of the potentialconsiderations.

Battery basics(page 24)


Buying a solar battery(page 46)

Guide focus areas

Guide focus areas

Guide focus areas

Sell excesselectricity

Power outagebackup

Preferredchoice

Practical examples

The NSW Home Solar Battery Guide page on the Energy Saver websiteprovides practical examples to help demonstrate how households, with varyingscenarios, decide on the best solution for them.



Section 1


Understandingyour energy useHousehold energy use 13

Find and understand your energy information 16

Easy things to do first 18

Section 2

12

Household energy useWhen considering a battery, it is important to understand how much energy you use in yourhome and when you use it.

To correctly size and design your batterystorage system, you need to understand howyou are already using energy in your home.

This is useful for two reasons:

1. to avoid using power when it is mostexpensive

2. to find the right battery size by knowinghow much excess solar you have and whenyou use power.

The appliances using the most energy inaverage NSW homes are hot water systems,fridges and heating and cooling systems (seeFigure 2 below). Most homes use the highestamount of energy in the early morning as wellas late afternoon and evening (see Figure 3on page 14).

This means households are not always usingenergy during daylight hours, when the solarpanels are producing electricity.

Figure 2: Typical energy consumption for an average household in NSW2

Other 3%

Hot water 40%

Refrigeration 11%

Cooling 6%

Computing 6%

TV &entertainment 7%

Cooking 4%

Clothes dryer 2%

Washing machine <1%

Dishwasher 4%

Lighting 7%

Heating 10%


Section 2

Measuring energy

There are two units to measure energy. One isthe power used at a given moment in kilowatts(kW), the other is the total energy used orproduced in kilowatt hours (kWh). If your solarproduces 5 kW of power for 4 hours, then thetotal energy produced is 20 kWh.

It works the same way for consumption.If your air conditioner uses 1.5 kW of powerand you leave it on for 13 hours, it will haveconsumed about 20 kWh (1.5 kW multipliedby 13 hours) as shown in Figure 4 below.

Figure 3. Typical household energy usage pattern

Figure 4. Guide for calculating usable power from solar power generation

The below figure provides a guide for calculating usable power from solar generation,based on an equivalent of 4 hours of sun and a 90% round-trip efficiency of the battery.

whichcouldpower5 kW

solar system4 hours

of sun20 kWhof energyproduced

1.5 kWrated appliance

13.3 hoursrunning time

for

(If the solar energy wasstored in a battery)

(a 5kW system doesn't produce5kW electricity all the time

during the day)

Morning peak

AM NOON PM

Evening peak

En

erg

y u

sag

e

Energy use from the grid


Section 2

NSW Home Solar Battery Guide 15

Find and understand yourenergy informationBefore purchasing a battery, it is important to understand your energy consumption and energycosts, as well as alternative ways to use less energy.

There are several sources of informationto help understand how you are currentlyusing energy. These include:

Electricity bills

Compare your daily average consumption foreach billing period. This will indicate whetheryour consumption is increasing or decreasingand will show you how your energy usagevaries across different seasons. If your bill isbased on estimated usage, ask your retailerfor accurate values.

Read the ‘Tariffs’ box on the following pagefor more information about what makes upyour bill.

Meter data

Data may be accessible via your meterdepending on the kind of meter you have.Older meters are only read periodically, whilenewer meters generally provide more detail,for example half-hourly grid import andexport data.

From December 2017, all new solar systemsand new connections would be connected to‘smart’ meters that send information aboutyour energy usage back to the grid.

Your energy retailer and network providerkeep smart meter data and are required toprovide it to you within 10 business days uponrequest. More conveniently, many energyretailers now have online portals where youcan log in and access your usage data.

Solar inverters

If you already have a solar system, a solarinverter collects data about energy generatedby your solar panels and most display certaindata on a small screen.

Many inverters are able to upload data in realtime to an online web portal or smartphoneapp where you can access your usage data.

In-home displays

You can receive detailed data from in-homedisplays. Simple displays show data aboutone appliance, while more sophisticated onesare WiFi connected and can tell you how thewhole home is performing on your smartdevice or computer.


TariffsA tariff is the rate you pay for grid electricity. It is usually composed of a fixed dailycharge (in cents per day) and a usage charge (in cents per kWh). The usage charge canvary at different times of the day, days of the week or months or seasons of the year.

Most households in NSW are currently onflat (or nearly flat) tariffs. That is, you paythe same amount for electricity all dayand night, plus the fixed daily charge.

Many solar and some other householdsare on a time of use tariff. This tariffcharges more for peak periods and lessfor shoulder and offpeak periods (seeFigure 5 below).

Retailers also offer demand-basedtariffs to customers with a smart meter.This tariff structure includes a demandcharge which is based on maximumpower demand the customer puts on thenetwork at any one time. Demand-basedtariffs encourage customers to spreadtheir electricity usage over time ratherthan all at once. To benefit from demand-based tariffs, you need to be vigilant inmonitoring power usage to avoid spikesin demand.

From July 2019, retailers are requiredto make a default market offer tohouseholds to ensure that annual pricesare capped, and price offers can becompared across different providers.The default market offer is set by theAustralian Energy Regulator each yearfor each electricity distribution zonebased on average usage.

In the future, more households may beencouraged to move to time of use andother new tariffs which better reflectthe pressure on the network duringpeak periods.

A controlled load tariff refers to aseparate tariff and meter with lowercharges. This tariff can only be appliedovernight by using special appliancessuch as hot water systems, some poolpumps and slab floor heating. Currently,home battery charging on controlled loadtariffs is not available so if you chargeyour battery from the network it wouldbe on a different tariff.

Figure 5. Example of time of use tariff periods

PeakTariffs are

highest.

PeakTariffs arehighest.

OffpeakTariffs arelowest.

ShoulderTariffs are

average.

Lowest

Average

Highest

Tariff periods:


Section 2

Easy things to do firstIf you are mainly interested in a battery to save money on electricity bills, there are somesimple steps you can follow to take control of your energy use and save money, even without abattery. In terms of value for money, there is a simple hierarchy.

1. Shop around for the best price

Competitive pricing and discounts

Find the most competitively pricedretailer to help you save moneyeach year and ask for discounts fordirect debit or on-time payments.You should make sure you areon the most appropriate type ofretail tariff to suit your needs. Visitenergyswitch.service.nsw.gov.au tohelp find the most competitive offer.

2. Reduce your householdconsumption

Use less energy

Replace old light bulbs with LEDs,switch off appliances and lightswhen not in use, use less hot water,have shorter showers and washclothes in cold water.

Upgrade your home insulation

Good building insulation includingceiling batts, gap sealing andwindow shading, may have ashorter payback period than eithersolar or batteries.

Purchase energy efficient

appliances

Energy efficient appliances, withat least four stars on their EnergyRating label3, may cost less overthe life of the product, despite ahigher upfront cost.

3. Make the most use of your existingsolar energy

Change your habits

If you have existing solar, runappliances such as dishwashersand washing machines when thereis sunlight. If your house is wellinsulated, pre-heat your house (inwinter) or pre-cool your house (insummer) while your solar system isproducing energy to reduce eveningconsumption from the grid.

Engage an expert

Arrange an electrician to rewireyour hot water tank so it usesyour own solar panels and whenreplacing an existing gas or electricstorage hot water system, considerreplacing with a heat pump hotwater system.

4. Increase your rooftop solar power

Add more solar panels

Install a rooftop solar systemor add more panels to yourexisting system to cover more ofyour consumption.

5. Installing a household battery

Is a battery the right solution?

If you have explored all of the tipsmentioned, only then considerinstalling a household battery.

Additional tips

For more tips on how to fine-tune the energy used in your home andsave money on your power bills visit:

energysaver.nsw.gov.au/households/fine-tune-your-home


https://energyswitch.service.nsw.gov.au/

https://energysaver.nsw.gov.au/households/fine-tune-your-home

Three easy alternatives to batteries

1 Heat pumps powered from solar

Heat pumps work like air conditionersin reverse, extracting heat from theatmosphere and using it to heat thewater in the tank.

If you set the timer to run when the sunis shining, it’s a win–win outcome forrenewable energy and low bills.

Modern heat pumps are highly efficient,producing up to five times the energyrequired to run them. You have to payfor the cost of the heat pump unit, but itshould save money in the long run.

2 Solar electric hot water

If you have an existing electric storagehot water system you can heat it directly(or as a priority) with electricity fromyour rooftop solar.

Doing this instead of using grid electricitycould save around $300 per year (on aflat tariff). About half of the electricity foryour hot water system would then comefrom your solar system, with the restcoming from the grid.

Using excess solar energy for hot waterheating may be more cost effective thanbattery charging, however you may needto make changes to how the hot waterheater is set up, particularly if it is alreadyon a controlled load. A smart hot waterheater may also be required.

3 Adding solar for early morning

and evening

Adding more solar panels to an existingsystem or installing a larger new solarsystem may have a shorter paybackperiod than buying a battery. This canbe especially beneficial where the newpanels’ setup helps produce energy laterin the afternoon or in the early morning.

You will need to receive professionaladvice about whether you can add morepanels to your existing solar systemor will need to install a whole newsystem, and whether this is beneficialto match your existing or plannedenergy consumption.


Section 2

Your homepower stationHow a home power station works 21

Battery basics 24

How green is that battery 29

Section 3

20

Figure 6. A home power station

How a home power station worksA home solar battery system is a mini power station that produces and stores solar energy toprovide power to your home and allow greater energy independence.

Solar panels on your roof generate energywhile the sun is shining, and this is used inyour home during the day. The unused solarelectricity is stored in an energy storagedevice installed in your home (the battery).This battery can help power your home whenthe panels aren’t producing electricity, suchas during the evening, when grid electricity isusually most expensive, or on overcast days.

Any solar energy not used in your home orstored in your battery is exported to the grid.Without a battery, exports can represent alarge share of the electricity generated from arooftop solar system, especially for householdswhich are not at home during the day.

Solar feed-in tariffs

If you have a solar system, any energyyou export usually earns a feed-in tarifffrom your electricity retailer. In NSW, theIndependent Pricing and Regulatory Tribunalhas recommended voluntary feed-in tariffsin the range of 6 to 7.3 cents per kWh for2020–2021.

Using power from the grid generally costs morethan that, so it makes sense for you to useas much of your own rooftop solar energy aspossible, rather than exporting it to the grid.

How a home solarbattery works

When you add a battery to a rooftop solarsystem (or install them together), the solarenergy not used at home during the day isused to charge the battery. Figure 6 illustratesthe setup of a home solar battery system.Figure 7 on page 23 shows the typical dailyenergy consumption for a NSW householdwithout solar, with solar and with solar andbatteries.

Some batteries can also be charged from gridelectricity, for example during offpeak times ona time of use tariff when electricity is cheaperthan during the day. Installing a battery willslightly increase total household energyusage as a battery consumes electricity in theprocess of storing it for later use.

Inverter(s)

Switchboardand meter

Energy management system

Household appliances

Local network

Solar panels

Battery

AC powercircuit

DC powercircuit


Section 3

Solar panels

Solar panels convert sunlight into directcurrent (DC) electricity. Some batteries chargedirectly with DC electricity, while others needto be connected after the inverter.

Because they have no moving parts, goodquality solar panels are usually reliable andcan last up to 25 years without a significantloss of output.

Inverters

Inverters manage the flow of electricity,converting the electricity generated fromthe solar panels or stored in the batteryinto alternating current (AC), the typeof electricity that powers your home.

It is beneficial to purchase a good qualityinverter for higher efficiency and because theirtypical lifespan is around 10–15 years. Ambienttemperature, unstable grid voltage, dust, heat,ventilation and vermin such as ants can affectthe lifespan of the inverter.

There are two main types of inverters used inresidential systems:

• Stand alone inverters: do not connect tothe grid and are used in offgrid homeswhere there is no grid connection.

• Grid-connected (or grid-tie) inverters:these inverters may be solar only,battery-only or hybrid. A hybrid grid-connected inverter can change bothsolar and battery current from DC to AC.Some grid-connected inverters can alsorun independently from the grid duringpower outages, if they are designed forthat. Inverters with this backup functionare usually more expensive.

Energy management system

An energy management system (EMS)controls the different components of yourhome power station, including your battery.The EMS is usually software and/or an energymanagement device.

They are not the same as batterymanagement systems (BMS). The BMScontrols the internal safety of a battery whilethe EMS helps to integrate it with the othercomponents of a home power station.

The EMS will decide when to:

• charge the battery from the solar system

• charge the battery from grid electricity

• discharge the battery to powerhome appliances

• export to the grid.

Some batteries come with an integrated EMS.If they don’t, it is important to know how thisfunctionality can be provided separately soyou can achieve the best use of your battery.In general, brands offering an integratedsystem (solar, batteries, inverters andsoftware) are likely to work better together,although you may pay more.

Some EMS may also enable intelligentbattery control where both energy demandand generation are predicted and usedto optimise electricity usage and costs. Insome cases, a separate energy managementdevice may be required to participate in avirtual power plant (VPP). See page 39 formore information.

Most inverters currently being installed don’t providebackup during a power outage. If you need backuppower capability, make sure you request it to be includedin your quote from your supplier.


How solar power and a battery affect your home energy

How solar power and a battery affect your home energy is demonstrated in Figure 7 below.This figure compares energy usage of a household with no solar or batteries, to a household withsolar only and with both solar and battery.

Household with no solar or batteries

Household with solar, no batteries

Household with solar, plus batteries

Excess solarexported to

the grid

Morning peak

Evening peak

Less excesssolar exported

to the grid

Energy use from the grid Energy use from solar

Energy exported to the grid

Less energyused fromthe grid

Batterycharging

Batterydischarging

EN

ER

GY

US

AG

EE

NE

RG

Y U

SA

GE

EN

ER

GY

US

AG

E

SO

LA

R G

EN

ER

AT

ION

SO

LA

R G

EN

ER

AT

ION

Figure 7. How solar power and a battery affect your home energy


Section 3

Chemistries

There are a range of chemistries currently available in the market.

• Lithium-ion: Network-connectedhousehold batteries are increasinglyfocused on lithium-based chemistries,which have seen a steady decreasein cost in recent years. Lithium-ionbatteries are also widely used in mobiledevices such as mobile phones ortablet computers.

These batteries are small and light incomparison to their capacity. Theycan be efficiently charged and haverelatively long lifespans.

There are many variants within thelithium-ion family, the two mainvarieties currently being sold arelithium NMC (nickel manganesecobalt) and LFP (lithium ferrousphosphate).

Lithium-ion technology generallydisplays high energy density (moreenergy stored in less space), high cyclelife (lifespan) and excellent chargeacceptance (allowing faster charging).Within the lithium-ion family, LFPtechnology is generally consideredsafer than NMC owing to betterthermal stability, but overall quality isthe key factor for battery safety.

• Lead-acid: Offgrid solar systems haveuntil most recently used lead-acidbatteries for solar storage. Lead-acidbatteries are relatively simple, reliable,and have a low upfront cost. However,they are less suited for solar storageapplications as they must be fullycharged regularly, are slow to charge,are quite heavy, and have relativelylow cycle life. They also require regularmaintenance and must be kept in aventilated environment.

• Other technologies: The other mainchemistry is ‘flow’ batteries, whichuse liquids to store energy. Theirmain advantages are safety, easeof maintenance and the ability tostore the charge for long periods.The main disadvantages are lowerenergy density compared to lithium-ion as well as being relativelymore expensive.

Other chemistries such as advancedlead-acid batteries are in variousstages of development and couldincrease their market share in future.

Battery basicsBefore purchasing a battery, you should check with your supplier for any information about thebattery that can affect how it should be used and what is covered in the warranty. This sectiondetails a few basic things you should be aware of.

Put simply, a battery is a box of chemicals.One type of chemical reaction stores energy(the charging cycle), while the reverse reactionproduces energy (the discharging cycle).Different battery chemistries have differentproperties that affect how they perform.

The following information provides anintroduction into the most important technicalspecifications you need to understand whenconsidering buying a battery.


Lifespan and warranty

You want your battery to last as long as thewarranty and hopefully well beyond it. Abattery’s lifespan will be influenced by severalfactors including the charge or discharge rate,the depth of discharge (DoD) employed in itseveryday operation and the temperatures thebattery is exposed to.

Some battery manufacturers’ warrantiesare for a specific time period (e.g. 10 years),but there are other warranty types. Theseinclude for a specific number of cycles, wherecharging and then discharging the batterymakes up one cycle, and energy throughput,which relates to a total amount of energythat is stored and delivered, across thebattery’s life.

Most lithium-ion battery warranties take theform of ‘this battery is warranted to retaina percentage of its storage capacity after acertain number of years or cycles, whichevercomes first’.

Some warranties may limit battery useto a number of cycle/s per day. In eithercase, the definition of a cycle is not alwaysclear, but should be understood whencomparing products.

Key factors that can void the warranty includeexcessive charge or discharge rates, exposureto high temperatures, and over-chargeor discharge.

Useable capacity

This is the amount of a battery’s total orrated capacity that is available for regular usewithout overly affecting its lifespan.

For example, a battery may have a ratedcapacity of 12 kWh, but its recommendeduseable capacity is only 10 kWh. If informationis not available, you should assume thataround 10% of the total capacity should notbe used on a regular basis. This needs to beconsidered when comparing batteries.

It is important that you understand your warranty.To avoid uncertainty make sure the supplier hasexplained it to you in detail.


Section 3

Depth of discharge

The depth of discharge is the recommendedmaximum discharge level of a battery. Somebattery chemistries can handle being fullydischarged on a regular basis; others can’tand will degrade quickly if fully drained often.Generally, lithium-ion batteries of either maintype (NMC and LFP) may be discharged to arelatively low level. Rough estimates for therecommended discharge level for lead acid,lithium-ion and flow batteries are shown inFigure 8 below. This should be consideredwhen designing a system.

Charge and discharge rates

The maximum charge and discharge rates arethe most power you can feed into a battery atonce, or the most power you can get out of a

battery at once. It is usually given in kilowatts(kW). Battery providers generally includeit in the product specifications. The higherthis rate, the more maximum power at oncethat can be accepted (charging the battery)or delivered (discharging the battery).

For example, a battery with a maximumdischarge rate of 2 kW should be able topower appliances that use up to 2 kW ofpower at any one time, such as a fridge,computer, TV and some lights. However,it may not have enough power if the air-conditioning, electric stove or microwave arealso running at the same time.

Most batteries have energy losses in thecharging process; this is the roundtripefficiency of the battery. For example, a10kWh battery with a roundtrip efficiency of90% will provide 9kWh of usable energy.

Figure 8. Recommended depth of discharge levels for different battery types

Most batteries are more efficient if you don’tcharge or discharge at the maximum rate. Theenergy management system may allow youto control these rates. This is an importantconsideration for households that wish to usea lot of energy at once.

For instance, a battery with a usable capacityof 10 kWh may have a maximum dischargerate of 5 kW. If discharged at 2 kW power,

it can deliver the full 10 kWh of energy. But ifdischarged at 5 kW power for a short time itmay only deliver a total of 9 kWh of energy.This is due to wiring and heat losses beinghigher at the maximum rate.

Choosing a lead-acid, lithium or otherchemistry affects how much of the totalcapacity can be used.

90%

STA

TE

D C

APA

CIT

Y (

kW

h)

BATTERY CHEMISTRY

Recommended discharge level (for long life) Recommended unused capacity

Lead-acid Lithium-ion Flow

* Some lithium-ion manufacturers allow 100% discharge.



Section 3

Coupling—should batteries share the inverter with solar?

‘Coupling’ refers to the way batteriesand solar panels are connected to theswitchboard. In a direct current (DC) setupa battery is connected to the same inverteras the solar system. In an alternating current(AC) coupled setup, a battery inverterconnects the battery to the meter box,separate from the solar inverter. The setupsare illustrated in Figure 9 on the next page.

It is best to discuss options and costs withyour installer. Here are a few reasons why youwould choose one over the other.

• DC coupled batteries are slightly moreefficient and are easier to get networkconnection approval because only oneinverter is connected to the network.However, DC coupling can be tricky forexisting solar systems, as it requires ahybrid inverter in place of the existingsolar inverter. If your existing solar inverter isrelatively new and working well you may notwish to replace it.

• AC coupled batteries are slightly lessefficient, but AC coupling allows powerfrom the battery to be used at the sametime as solar power, and usually allowsyou to charge the battery from the grid,which is not always the case for DCcoupled systems. An AC coupled batterycan be installed without any changes to anexisting solar system.

• Both AC and DC coupled batteries canbe designed to have backup functionalityduring a power outage, but check thespecifications of the products.

You should check with your supplier forthe most appropriate set up for yourcircumstances.


Figure 9. Comparing AC and DC coupled battery systems

DC coupled

Solar panels Solar panels

Solar inverter

Battery Battery

Hybridinverter

Batteryinverter



AC components and energy flowsDC components and energy flows

AC coupled


Section 3

How green is that battery?There are a number of things that you need to think about when considering the environmentalsustainability of particular battery types and products.

Currently, there are no independent sourcesof information or advice that rank differentproducts for their environmental performanceor impact. Nor is there an industry productstewardship scheme for the whole supplychain and product lifecycle that would putthe responsibility on makers and sellers toprovide this information. Both of these arelikely to happen in the near future.

In the meantime, here are some of the thingsto look for.

• The materials and energy used inmanufacturing and transportation(‘embodied energy’): Some battery rawmaterials are relatively cheap and plentiful(like lithium or lead), while others are rareand expensive (like cobalt). A solar systemthat includes a battery should offset theenergy used to manufacture it in aroundtwo years4.

• The energy efficiency and lifespan ofthe system in use: The longer a batteryis warranted to last, and the more energya battery is guaranteed to store withinits warranty period, the better the use ofresources to manufacture it.

• Whether or not the battery helps toincrease renewable and decrease fossilfuel generation: Unlike solar, installing abattery doesn’t automatically guaranteethat you are creating more renewableenergy. However, batteries may havea direct environmental benefit suchas allowing you to install an oversizedsolar system, reducing the use of dieselgenerators in offgrid situations or reducingthe amount of generation required in thegrid when used at peak times.

• End of lifecycle reuse, recyclingor disposal: Batteries are likely toconstitute a significant source of e-wastein future. However, organisations likethe Australian Battery Recycling Initiative,www.batteryrecycling.org.au are alreadyworking on a solution for waste disposaland recycling.

Further, the battery industry and theFederal Government are currently workingtoward establishing a voluntary schemefor battery stewardship covering alltypes of batteries. The intention is for thescheme to be extended to home batteries.The scheme will seek the responsiblemanagement of battery products fromdesign through to end of life by all partiesinvolved in the battery supply chain. Thestart of the scheme is planned formid 2020.

In the meantime, some batteries (such aslead-acid) have ingredients that are easierto recycle than others. Batteries may alsobecome reusable in new applicationsand installers could potentially offerused electric car batteries for your homepower station.

You could also ask your supplier if theyhave an ‘end of life’ policy, or somethingsimilar in relation to the disposalof batteries.


http://www.batteryrecycling.org.au

Buying GreenPower

You can make sure any grid electricityyou use directly or to charge yourbattery has zero net emissions bypurchasing 100% GreenPower throughan electricity retailer. Most retailers offera GreenPower product for all or part ofyour electricity consumption.

GreenPower is renewable energy sourcedfrom accredited solar, wind, bioenergyand mini-hydro generators acrossthe country.

GreenPower accredited electricity isadditional to the national RenewableEnergy Target and is strictly audited

to verify that the retailers ensure thatelectricity generated from accreditedrenewable energy generators is fed intothe grid on your behalf.

By purchasing GreenPower, you willbe able to lower your emissions and tocontribute to the growth of Australianrenewables at the same time, whetheryou decide to invest in a battery or not.

To find out more visit greenpower.gov.au


Section 3

http://greenpower.gov.au

Planning fora battery

Section 4

Options for adding a battery 33

Battery sizing 34

Future proofing 38

32

Options for adding a batteryIn most instances, you will be adding a battery to a new or existing rooftop solar system, unlessyou are thinking of buying a battery to operate on its own.

New solar and new battery

Installing a new solar system with your newbattery has both financial and practicaladvantages. The solar battery system usuallyhas a shorter payback period than the otherbattery options. This is mainly because thesolar system is what generates the financialsavings. You can have a single hybrid inverterinstead of two inverters and you can installa larger solar system with the extra powergenerated being stored and used later.

Addition of battery to existing solar

Adding a battery to existing solar, also calledretrofitting, has a longer payback period thannew solar and a new battery, often exceedingthe warranty period. Based on the current costof batteries this option may not pay for itself,but it will still improve your energyself-sufficiency.

It is important to determine whether yourexisting solar system is ‘battery ready.’ Usuallyyou will need to install a dedicated batteryinverter with your new battery. Most battery

products on the Australian market are now beingsold with an inverter, which may be integratedinto the battery unit or installed separately.

Some providers might offer to replace theexisting solar inverter with a single hybridinverter which connects to both the solar andbattery, but this is not possible in all cases.

Providers may also offer to connect thebattery to the existing solar inverter, withoutneeding a battery inverter, by fitting adedicated DC to DC converter between thesolar panels and the battery. This option willmean that the battery can only be chargedfrom solar, and not from the grid.

New battery without solar

A new battery without solar may be suitablefor households that want to charge a batteryfrom the grid at offpeak rates and then usethe energy in their home during peak periods.

In most cases, this option currently doesn’tmake financial sense, has the longest paybackperiod and is unlikely to recover the cost ofthe battery. It also does not have the benefitof providing any renewable energy for thehousehold to use.v

++

+ +


Section 4

Battery sizingChoosing the right battery storage size for your needs will depend on the size of your solar,how much energy you consume during peak periods, whether you want backup during a poweroutage and your financial considerations, including budget.

Choosing a battery

For bill-saving purposes, it is generally bestto buy a battery that you will regularly chargeand discharge to the recommended level.This requires excess solar during the dayfor charging, and demand outside of solargeneration hours for discharging.

You must be careful to not over-use a battery,for example by fully charging and dischargingtwo or three times a day. Doing this mightshorten its lifespan. You can usually set thisup in the energy management system or app.

The best way to choose the right size batteryfor your needs and budget is to get anindependent assessment from an accreditedinstaller or supplier.

To help you when you talk to an independentassessor, we have included some tips forbattery sizing in the box below, and someexample sizing for different households inFigure 10 on the next page.

To make the most

of your solar

Calculate how much excesssolar energy you will haveduring the day. This can be

done by subtracting theenergy consumed in yourhome during sunny hours

from the amount of energyyour solar system typically

generates in a day.

Decide whether you wantto store all your excesssolar or just the amountof energy you would useduring the evening peak.

To power your

house overnight

Calculate your excesssolar energy and your

overnight energy use, forexample by subtractingthe average daily solar

energy used in your homefrom your total average

daily consumption.

Size your solar and batteryso the battery can befully charged by solar

energy during the day anddischarged to cover your

electricity needs overnight.

To have backup for

multi-day outages

Your battery should bebig enough to cover

several days of energyuse, and you may

need an on-site dieselgenerator in addition to

battery storage.

Design your system likean offgrid setup, witha special inverter and

isolation switch.

Plan for a larger systemwith higher costs and lessefficient battery utilisation.

Battery sizing considerations

If you do not already have solar you will need to size your solar system appropriately.Speak to an accredited installer to help with solar sizing. The below are examples ofwhat you may want your battery for. These considerations may help you get a betteridea of what battery size you might need.


Practical examples

The below table includes practical examples of what battery size, investment andpayback may be required for different situations. The first three lines show the person’smotivation, their power use and whether they already have solar. In the lower sectionyou can see what their decision might be, including new or extended solar, batterycapacity and what that means in terms of costs and savings.

Figure 10. Practical examples of solar and battery sizes

*The annual savings from the solar battery system are not evenly split between the solar and batterycomponents of the system.**Annual savings from solar storage is $130, while annual benefit from avoided power outages is assumedto be worth $400.

Example 1:Isabella

Example 2:Ali

Example 3:Wei

Example 4:Scott

Overview andmotivations

Find simpleways to reduceher energy bill.

Reduce carbonfootprint andbe an earlyadopter of

new technology.

Rely lesson the gridand earn

money fromgrid support.

Becomemore self-

sufficient andhave home

office backup.

Dailyconsumption

10 kWh 10 kWh 25 kWh 20 kWh

Existing solar 2 kW — 5 kW 4 kW

Their investment

New solar

Buys energyefficient

appliancesinstead

4 kW 5 kW —

New battery — 2.4 kWh 13.5 kWh 13.5 kWh

System cost $2,800 $9,000 $18,500 $13,500

Annualsavings

$520 $870* $1,500* $530**

Payback 5 years 10 years 12 years 26 years

Additional practical examples

The NSW Home Solar Battery Guide page on the Energy Saver websiteprovides the full practical examples summarised in the table above.



Section 4


Backup power capability

Standard solar and battery systems do notwork when there is a power outage. Forbackup power your system needs an isolationswitch. There is usually an additional cost forthe isolation switch and its installation.

During an outage the switch disconnects yourwhole house from the grid. This is necessaryto protect anyone fixing the grid from gettingan electric shock from your battery.

For most NSW households, power outagesare rare so you may not need backuppower capabilities.

Sizing for backup orgoing offgrid

The less reliant on the grid you wish to be,the larger the battery system you will need.Offgrid means not being connected to thelocal electricity grid at all. Completely offgridhouses need to generate and store electricity,with no reliance, or support, from the grid.

If you want backup for multiple days, or areconsidering going offgrid, then all of yourconsumption will need to be covered eitherdirectly by a rooftop solar system or othergenerator, or indirectly by using power whichis generated earlier and stored in a battery.

While sizing for backup or going offgrid cangive you control over your energy supply, thecost could be multiple times that of a grid-connected system.

Standard solar and battery systems do notwork when there is a power outage.



Section 4

Future proofingIn the fast-changing home battery market there is a range of factors to consider when trying to‘future proof’ your investment decision.

Timing

If bill savings are your main motivation, thebest way to future proof your investmentwould be to only buy a battery when youare confident you will get a payback withinthe warranty period. With prices expected tofall steadily, that could mean a wait of only afew years.

Solar now, battery later

You may wish to install solar now and adda battery later, when prices fall further. Inthis situation, many customers wonderhow to ensure their system—particularlytheir inverter—is ‘battery ready’. Here aresome options.

• Solar with solar inverter: You might simplyinstall solar with a solar inverter. When youdecide to add a battery, you can eitherAC-couple the battery (via the battery’sown inverter) or replace the solarinverter with a hybrid inverter that canaccommodate a new battery.

You should be aware that some installersmay be unwilling to replace your oldinverter to accommodate a new battery.In doing so they become responsible forensuring the whole system meets thelatest standards.

• Solar with hybrid inverter: Alternatively,you may install solar with a hybrid inverter,ready for the battery later on. However,there is a risk that by the time you installthe battery the inverter may be obsoleteor unnecessary.

Consider future tariff changes

Future tariff changes can impact the benefitsa battery provides. For example, if yourelectricity tariff (the amount you pay forpower from the grid) increases in the future,you are more likely to benefit from storingand using the electricity you produce.

Start small

Some batteries are designed to be modular.Having more storage is then simply a matterof adding more units. You will need to makesure that the inverter capacity matches yourneeds. Some modular batteries include aninverter in each module.


Sell your energy when marketprices are high

As an alternative to selling your excess solar orstored battery energy into the grid for a fixedtariff, you can also buy software that allowsyou to sell your excess energy into the grid attimes when energy market prices are high.

Some providers are currently offering thisservice. Please note, the software may havean additional cost, and the provider maymake this service available only infrequently.Therefore, at the moment, this option shouldbe considered as supplementary.

In the future, new electricity business modelsmay emerge which include a wider range ofofferings to households that can sell theirexcess energy back to the grid, or to otherlocal households or businesses.

Virtual power plants

A virtual power plant (VPP) is created by anetwork of home solar panels and batterystorage systems all working together togenerate, store and feed energy back intothe grid.

Energy from the home solar panels andbattery systems linked to a VPP mainlyprovide electricity for the house where theyare installed. However, energy generated orstored by the system, and not used by thehousehold, can automatically be dispatchedand sold back to the grid when needed most.This helps to reduce demand and pressure onthe network.

VPPs are offered by some retailers andspecialist providers. The benefits varydepending on the provider. Some offer a fixedpayment back to the customer, a reduction inthe cost of the battery or a payment every timethe battery is being used as part of the VPP.

This technology is in early stages of uptakein Australia but is likely to increase in thecoming years.

If you are interested in being part of a VPPand improving your return on investment:

• Check with your installer to see if yourbattery system is either capable or readyto be operated in a VPP.

• Sign up to a VPP initiative to complementyour solar battery.


Section 4

Will a batterysave me money

Section 5

Calculating the payback period 41

Typical payback periods in 2020 42

Are batteries a good investment right now? 44

40

Calculating the payback periodThe ‘payback period’ is the time it takes for a battery to pay for itself with savings in yourenergy bills. In some cases, a solar battery system may never achieve savings to pay for itself.

To estimate the payback period in years,simply divide the upfront system cost by theprojected annual savings in your energy bills.If you have a warranty that is less than thepayback period, the battery system may notpay for itself before the warranty expires.

Figure 11 below provides a simple exampleof how to estimate your payback periodbased on a system cost in year one, a yellowrectangle for each year of savings untilthe system has paid for itself and a greenrectangle for each year of additional savingsprovided by the battery after the paybackperiod. The dotted line indicates the pointat which the battery has achieved enoughsavings to pay for itself. In this example thepayback period is eight years.

If the warranty period is 10 years, the exampleshown would suggest a relatively safeinvestment because the payback period isshorter than the warranty period. If the warrantywas less than eight years in this example, youwould be taking a risk by assuming the batterywill be able to pay back its cost.

A number of online calculators exist that canhelp you work out the payback period once youhave received one or more quotes. These areimportant because they can help you comparethe different quotes. For example, you shouldtry to understand what your ‘annual savings’would be depending on if you will use the fullbattery capacity every day, or what part of thesavings are due to the battery itself and whatparts are due to installing solar panels.

PAYBACKPERIOD

10 2 3 4 5 6 7 8 9 10 11

Additional savings after payback

YEARS

Payback period

Upfront cost

Annual savings

12

PAYBACKPERIOD

10 2 3 4 5 6 7 8 9 10 11

Additional savings after payback

YEARS

Payback period

Upfront cost

Annual savings

12

Figure 11. Understanding thepayback period

For a more accurate payback periodcalculation, you would need to includea range of additional factors such as:

• actual level of discharge of the batteryover the course of the year, taking intoaccount energy use patterns and solargeneration (where solar exists). This willalways be less than the usable capacitymultiplied by 365 days

• reduction of battery capacity overits lifespan

• potential future changes in retailelectricity prices

• efficiency losses between solar, the batteryand your appliances.

A list of detailed battery sizing and payback calculatorscan be found in the ‘Where to go for more help’ sectionon page 64 of this guide.


Section 5

Typical payback periods in 2020A new rooftop solar system, without a battery, usually has the shortest payback period.However, payback periods for batteries are getting shorter.

In many cases, installing a new solar systemwith a new battery can pay for itselfwithin 10 years, especially for higher thanaverage consumption households (over16 kWh per day) on time of use tariffs.But this doesn’t apply to below averageconsumption households.

The addition of a battery to existing solar, alsocalled retrofitting, currently has the longestpayback period, often exceeding the warrantyperiod. While this option may not pay for itself,it still improves your energy self-sufficiency.

Figure 12 below shows the relative paybackperiods for different battery system options.

New solar

New solar + battery

Retrofit battery to existing solar

Payback periods

SA

VIN

GS

CO

ST

S

YEARS

Figure 12. Relative payback periods in 2020 for different battery system options



Section 5

Are batteries a goodinvestment right now?It is important to know whether battery storage purchased today will deliver the financialbenefit that you are looking for. There are some circumstances where a battery may alreadymake financial sense5.

High consumption

You have higher than averageconsumption during peak times, are on

a time of use tariff, and are planningon installing a new solar system with

your battery.

Location limitations

A new, rural grid connection wouldbe expensive and going offgrid

would be a cheaper alternative. Thiswould still have reliability, customerprotection and other implications.

Export limit

You have, or want to install, a largesolar system but the local electricity

network has imposed an exportlimit on your solar system, so some

solar generation will go to wastewithout a battery.

Special programs

A special program is available in yourarea, such as a Virtual Power Plant trial,

including a battery subsidy. Carefullycheck installer certification, warranties

and customer support and read thisguide for other useful information.

This list might expand within a few years to include most grid-connected householdsthat export solar power to the grid. However, the optimum battery size for most ofthese households is likely to be relatively small.


Summary

• New solar: A new rooftop solar systemwithout a battery currently pays foritself sooner than one with a battery.

• New solar and battery: In many casesa new solar system with a batterycan pay for itself within 10 years. Thesolar component of a solar batterysystem will provide the majority ofthe savings.

• Existing solar: Currently, retrofittinga battery to existing solar doesn’tmake much financial sense, but thatmay change in the next few years.The best outcome for retrofits are forlarge-consumption houses with largesolar systems.

• Battery size: The payback time isgenerally quicker for a small battery,when paired with a new solar system,as opposed to a large one.

• Location: Sunnier inland locations (e.g.Armidale, Broken Hill, Wagga Wagga)tend to pay back one year quickerthan coastal locations.

• Battery costs: Battery costs areexpected to continue to decline overthe next few years, which will reducepayback times.

• Tariffs: Current time of use tariffs arebetter for battery payback than flattariffs. However, future tariff trendsare uncertain.

These messages are based on cost modelling undertaken for this guide in 2020by ITP Renewables.


Section 5

Buyinga solar battery

Section 6

Getting a quote 47

Choosing an installer 48

Options for buying 50

Connecting to the grid 51

46

Getting a quoteIf you have decided a solar battery system is right for you, we recommend you have yourinformation and requirements ready and seek at least two quotes from reputable installers.

Installer information tips

Here is a list of things that may be useful foryour installer to know to prepare a quote.

✔ General

• Meter type, location and single or three-phase power supply type (an installer cantell from what’s in the meter box)

• Electricity bill information such as annualconsumption, metering data, retailer name,tariff type and discounts

• Appliances that consume a lot of powerand their age (e.g. hot water systems,refrigeration, pool pump and heating orcooling systems)

• Usage patterns such as when you use themost energy (daytime, evening, or a mixof both)

✔ Solar

• Approximate area of unshaded roof facingnorth, east and west

• Roof height and material (e.g. tile,colorbond)

• Approximate roof pitch

• Existing solar system size

• Preferred budget, system size, technologyand/or brands

✔ Battery

• What you want a battery to do(e.g. maximise use of your solar orbackup power)

• Preferred budget, system size, technology(chemistry) and/or brands

• Whether you have interest in selling excesssolar or battery energy into the grid

Understanding the supplier market

The Clean Energy Council, an industry peak body, manages an accreditation schemefor solar and battery installers on a national level, including NSW. Accredited installersmust comply with accreditation requirements, for example in how they provide you witha quote and the minimum warranty they need to provide for an installation. They mustalso ensure that your system meets industry best practice standards and all relevantAustralian Standards. Only Clean Energy Council accredited installers can access theAustralian Government’s incentives for solar systems.

The main parties involved in the sale and installation of battery storage systems arethe retailer, designer and installer. The roles of each are explained in the Clean EnergyCouncil’s Guide to Installing a Household Battery Storage System. Visit:

cleanenergycouncil.org.au/consumers/buying-battery-storage

These roles can be filled by one individual company or two or three entities may beinvolved if companies subcontract out their designs and/or installations.


Section 6

https://www.cleanenergycouncil.org.au/consumers/buying-battery-storage

Choosing an installerHere are some factors to consider when choosing an installer:

• Is the installer accredited with theClean Energy Council (CEC)?

• Is the solar retailer accredited withthe CEC?

• Are they licensed to install this kindof system?

• What is their recent experience installingthis particular product?

• What happens if the system needs to befixed under warranty and their business isno longer operating?

• What maintenance is required? Who cando it?

• Are replacement parts readily available?

• How long have the manufacturers beenin the industry, and do they have alocal office?

• Which warranties are the installer’sresponsibility and which are themanufacturer’s?

We recommend you schedule a consultationat your home. Be wary of any installers whoclaim to be able to provide a firm quotewithout visiting your home. Try to get atleast two quotes, with different system sizesand brands, so you can choose according toyour needs and budget. Take your time whenmaking your decision.


What a quote should contain

When you get quotes back from installers, here is the information they should contain.

✔ Installation compliance: Confirmationthe battery system will be installed inaccordance with AS/NZS 5139:2019,Electrical installations—safety ofbattery systems for use with powerconversion equipment. The installershould also include any additionalitems and costs required for theinstallation to meet the standard, forexample fire-proof sheeting.

✔ Battery specifications: Includingbattery and inverter size (if separate),maximum charge and discharge rateand recommended depth of discharge.

✔ Energy assessment: A basic energyassessment of the premises, withrecommendations for energy-use reduction.

✔ Potential issues: A note of what, ifany, electrical issues may need tobe addressed before the system canbe connected.

✔ Itemised prices: A detailed list,with individual prices, of the systemcomponents you would be buying.

✔ Additional costs: Any additional costsfor the installation (e.g. asbestosremoval and switchboard or wiringreplacement).

✔ Solar system energy output: Anestimate of the energy output ofthe solar system, the expected self-sufficiency level and potential savings.

✔ Emissions estimate: An estimateof the CO2 emissions reductionof the system.

✔ Guarantees and warranties: Includingspecific exclusions and conditions forthem to stay valid (e.g. the batterylocation and temperature range)and what to do when somethingdoesn’t work.

✔ Customer references: If requested.

✔ Energy management system:Information about the energymanagement system and how it isaccessible, for example via an onlineapp on your smartphone.

✔ Network connection paperwork:Help with the network connectionpaperwork and the small-scaletechnology certificates applicationif also installing solar.

✔ Additional information: Includingwhen it will be completed, whetherthe price is guaranteed until then,where the battery will be installed,compliance with the manufacturer’srequirements and whether the batterycan be relocated if you move house.


Section 6

Extra resources

The Clean Energy Council has a list of accredited installers.

cleanenergycouncil.org.au/consumers/buying-solar/find-an-installer

The Clean Energy Council also has a list of battery products which have beenindependently tested to meet industry best practice for electrical safety andquality standards.

cleanenergycouncil.org.au/industry/products/batteries/approved-batteries

There is currently a New Energy Tech Consumer Code being developed which offersconsumers protection during the sale of new energy technology. The code will seta minimum standard of customer service for customers looking to buy new energytechnologies. Customers should refer to cleanenergycouncil.org.au/advocacy-initiatives/behind-the-meter-code for further information on the status of the code.

Options for buyingThe most cost-effective way to buy a solar battery system, or a battery system, is usually tobuy it outright. This is because you don’t have to pay finance company fees and interest. Somealternative buying options are listed below.

Note that the information in this guide should not be taken as financial advice and has beenprepared as general information only. You should consider all offers carefully and if needed, seekadvice before investing.

Empowering Homes Program

The Empowering Homes program provides interest-free loans for solar battery systems to eligible NSW residents. Loans of up to $14,000 for a solar battery system, or up to $9,000 for adding a battery to an existing solar system, will be available to owner-occupiers with an annual household income of up to $180,000.

The program was launched in February 2020. It is initially running as a pilot for eligible postcodes to refine its design before rolling out across the state. For more information please visit, energysaver.nsw.gov.au/solar-battery-loan-offer

Lease

Some solar suppliers have leasing programs which they are now extending to solar battery systems. They own, install and maintain the system and you pay them a regular fee based on either a fixed monthly price or on the energy you use from the system. You should only explore this option if you are sure that

the electricity bill savings will outweigh thelease repayments over time.

Finance

Some solar installers will offer finance, typicallyfrom an external funder. Separate finance isalso available from financial institutions.

Watch out for cheap finance attached to aninflated system price, or direct debit fees thatcontinue after you have repaid the loan.

Bulk buy

Occasionally, companies or organisationspromote solar and/or batteries at lower pricesfor buying in bulk than would be available forindividual sales. By signing up large numbersof customers in the same area in advance, thepromoters may be able to get better dealsfrom manufacturers and suppliers, which theycan pass on to you. When assessing a bulkbuy program, you may also choose to seekone or two quotes from other local installersso that you can compare offers.


https://www.cleanenergycouncil.org.au/consumers/buying-solar/find-an-installer

http://cleanenergycouncil.org.au/industry/products/batteries/approved-batteries

http://cleanenergycouncil.org.au/advocacy-initiatives/behind-the-meter-code

http://cleanenergycouncil.org.au/advocacy-initiatives/behind-the-meter-code

http://energysaver.nsw.gov.au/solar-battery-loan-offer

Connecting to the gridYour installer will manage the grid connection process for you. The process is oftenstraightforward, although additional time or fees are sometimes incurred for connecting largersystems. In some cases, you may also need to replace your electricity meter.

Network connection approval

To connect a solar or solar battery systemto the grid, your installer first submits anapplication to your local electricity network.Upon approval, the installer installs thesystem and supplies both you and theelectricity network provider with a certificateof compliance for electrical work (CCEW).

For new or alterations to a solar or solarbattery system, a connection application isto be submitted. If you are adding a batteryto an existing inverter, the installer will needto submit a connection form to the networkservice provider. This is also the case foraltering the panels with an existing inverterand removing equipment.

Distributed energy resources register

A distributed energy resources (DER)database was launched in December 2019by the Australian Energy Market Operator toprovide greater visibility over DER devices,such as solar and battery systems, to bettermanage the electricity grid.

The DER register contains information aboutyour solar and battery system and its locationin the network. Your installer is responsiblefor obtaining this information from you andproviding it to the DER register.

Automatic connection approvals

All NSW network providers offer automaticconnection approvals for smaller systems.Where the total system inverter capacity islarger than 5 kW, individual assessments maybe needed, and additional fees may apply.

Network providers may offer automaticapprovals for solar battery systems withcombined inverter capacities over 5 kW aslong as export to the grid is limited to 5 kW.Check with your installer or network providerwhat the exact requirement is.

Remember, many older household electricitymeters in NSW are not suitable for solaror batteries. Your installer may be able toarrange the installation of a new smart meter.It may be free through your electricity retaileror the cost should be included in your quote.

New meters and other costs

Any time an electrician is working onyour house wiring, there is a chance theywill discover existing issues. For example,the switchboard may be too small toaccommodate the new switches required foryour battery, or it may contain asbestos andbe dangerous to work on, so it may need tobe upgraded and re-wired. Such activitieswould incur additional costs.

Extra resources

Installing a smart meter often makes sense and may be required for asolar battery installation. For more information about smart meters, seethe ‘Additional Information’ on page 58, or visit:

energysaver.nsw.gov.au/business/evaluate-your-usage/smart-meters


Section 6

http://energysaver.nsw.gov.au/business/evaluate-your-usage/smart-meters

Owninga battery

Section 7

Managing your battery 53

Monitoring and maintenance 55

Safety 56

52

Figure 13. How a solar buffer battery management strategy works

Managing your batteryTo get the most value out of your battery and manage it effectively, choose the batterymanagement strategy which best meets your needs.

There are two main battery managementstrategies currently in use:

1. solar buffer—when you want to use asmuch of the electricity produced by yoursolar system as possible

2. tariff optimisation—when you want tominimise the cost you pay for electricity.

Your battery supplier should help you todecide which is best for your needs and helpyou with setup.

You may be offered an energy managementsystem (EMS) to apply your batterymanagement strategy. You will need tocarefully consider the costs and benefits ofthe EMS over time.

Solar buffer

Solar buffer, commonly called PVself-consumption, is the most commonbattery management strategy. Under thisstrategy, the battery is charged from yoursolar panel rather than the grid.

Figure 13 below shows how this managementstrategy works. In the first instance, your solargeneration is used to supply your householdappliances, just like a solar system without abattery. Any excess solar is then used to chargethe battery. Exports to the grid will only occurwhen the battery can’t absorb the excess solar.

When your energy consumption is greaterthan what is being generated by solar, energyis discharged from your battery to avoidimport from the grid.

Appliances

Battery

Exportedto the grid

Solar

When you generate solar power, asolar buffer prioritises the order inwhich it is used.

Solar

Appliances

Importedfromthe grid

When you use energy, a solar bufferprioritises where it comes from.

Battery


Section 7

Figure 14. How a tariff optimisation battery management strategy works

Tariff optimisation

Tariff optimisation operates like solar bufferbut has additional features that are usefulwhen a time of use tariff applies (see page 17for a reminder about how time of use tariffswork). Under this strategy the battery maysometimes charge from the grid overnightduring the offpeak period.

Figure 14 below shows how this managementstrategy works. The EMS normally usesweather forecasting to estimate the day’ssolar generation and consumption. It thendecides how much to charge the battery tominimise the amount of grid import that willbe required during the peak period. It alsotries to avoid charging the battery more thannecessary, as this may result in excess solarexports to the grid during the day.

The strategy is as follows (weekdays only):

• Morning use is met from the partlycharged battery when the morning peaktariff for electricity is expensive.

• During the day rooftop solar powers homeappliances and charges the battery whenthere is excess solar energy.

• In the evening when the peak electricitytariff is expensive the battery discharges topower home appliances.

• Overnight the battery may charge fromgrid electricity, taking advantage ofcheaper offpeak tariff price.

Medium(shoulder)

High(morning peak)

High(evening peak)

Low(offpeak)

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Monitoring and maintenanceMost new batteries require minimal maintenance by owners6. They should come withinstructions on any checks that need to be completed, such as keeping them clean and freefrom insect and animal infestation.

A periodic service by an accreditedinstaller or other professional is usuallyrecommended, this may have a costassociated with it. They can providefeedback on the system’s performance andhelp you understand if there is anythingmore you can do to get the most out ofyour battery. They should also provide youwith the manufacturers’ manuals to helpyou identify when your system may behaving problems.

If your system has failed or seems to beperforming below expectations, contactyour installer.

If your installer is not available, your nextoption is to contact your manufacturer. Incases where your installer or manufacturercannot deliver the expected service withinthe warranty period, you should contactNSW Fair Trading.

As most solar systems and batteries areinternet-connected devices, cyber securityis another area of consideration. Mostreputable brands may have arrangementsin place to ensure products are cyber-secure through software updates. Thereis significant research currently beingundertaken, including by the CSIRO inAustralia, on this subject.

Your rights and protections

As with other consumer products soldin Australia, you are entitled to the fullprotection of the Australian ConsumerLaw. In NSW, this law is administered andenforced by NSW Fair Trading,www.fairtrading.nsw.gov.au. You shouldcontact them if you have concerns about:

• not getting what you expected fromthe quote

• overcharging

• defective installation

• excessive delays in installation andgrid connection

• the system not performing accordingto the quote and warranty

• ongoing communication problemswith the supplier or installer.

If you have concerns about your electricityretailer, contact the Energy & WaterOmbudsman NSW, www.ewon.com.au

The consumer protections provided bythe law may exceed those specified in themanufacturer’s written warranty. Oncethe warranty period has expired, yourbest option is to contact an electricianwith solar and battery experience andaccreditation. If expensive work isrequired, we recommend you seek atleast two quotes.

Make sure you keep the sales invoiceand warranty documentation whenpurchasing your battery.


Section 7

http://www.fairtrading.nsw.gov.au

https://www.ewon.com.au/

SafetyThe following section provides some simple tips to consider when it comes to battery safety.For major incidents, call emergency services immediately. In the case of a fire or flood, pleaselet them know about the battery and its location.

Battery location tips

Most home batteries can be installedoutdoors7. However, their lifespans and safetymeasures can be improved when:

• they are located in a stable, cool andinsulated area that is not in direct sunlight

• the enclosure is vermin-proofed

• they cannot be accessed by children

• they are not installed in habitable rooms8

for compliance with AS/NZS 5139:2019

• they are clear of obstacles

• they are clear of flammable objects orthose that could conduct electricity in oron the battery enclosure

• heavy household equipment is not storedon top of a battery

• it displays appropriate signs relating tosafety, warnings and shutdown procedures.

While most batteries are extra-low voltage,they still have the potential to cause serious,sometimes fatal, accidents. When installedcorrectly though, they are generally lowrisk. Safety signs are a requirement and careshould be taken at all times.

In the unlikely event of a fault, somebatteries can catch fire, and others canrelease flammable hydrogen gas, so theyrequire proper ventilation9. These risks, whileunlikely, may affect your home insurance.It is important to check with your insurerbefore installation.

Lithium batteries, the most common batterytype, are generally fully sealed and duringnormal use do not release any gases anddo not need ventilation. But the batteryenclosure should include ventilation fortemperature control, particularly in theevent of a fire.

Standards and regulations

There are several Australian standardsrelating to battery design and installationwithin buildings. Most relate to traditionallead-acid technology and do not addresslithium-based chemistries and network-connected solar battery installations.

In October 2019, Standards Australiapublished a new standard (AS/NZS5139:2019) for the safety and installationof battery systems connected to powerconversion equipment for the supply ofAC and DC power. This standard includeslithium-ion technologies.

The new standard introduces a numberof safety measures for battery installationin homes. One of the new key measuresis, where a battery is installed against awall with a habitable room on the otherside, a non-combustible material such as

a cement sheet is required between thewall and battery.

To ensure you are confident that yourhousehold meets the required standards,please ask your supplier and installerabout how their products and installationconform. Battery storage standardscontinue to be refined and new standardsare expected as the industry evolves.

The Clean Energy Council has developeda battery product safety guide based onindustry best practices. The guide onlyapplies to lithium-based battery storageequipment including battery modules,pre-assembled battery systems andpre-assembled integrated batteryenergy storage systems.

Visit www.batterysafetyguide.com.auto find out more.


http://www.batterysafetyguide.com.au

For major incidents, call emergencyservices immediately.

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Section 7

Additionalinformation

Section 8

Frequently asked questions 59

Glossary 61

Where to go for more help 64

Modelling assumptions 67

Notes and reference 68

58

Frequently asked questions

✔ Can I get government support to install a home battery?The NSW Government’s Empowering Homes program is providing access to interest-free loans to eligible homeowners so they can install a solar battery system. The program has initially been launch as a pilot in eligible postcodes. For more information visit energysaver.nsw.gov.au/solar-battery-loan-offer

✔ Can I recharge overnight from the grid on my offpeak tariff?Overnight ‘controlled load’ offpeak power is installed in many properties on a separate circuit with a dedicated second meter. It is used to provide cheap power to hot water systems, some pool pumps and slab floor heating. None of the three electricity network providers in NSW currently allow overnight home battery charging on an offpeak controlled load circuit and tariff.

However, home batteries connected to the main circuit can be charged at offpeak rates for households on a time of use tariff. When this is done, households can partly offset the cost of their battery purchase by charging the battery at the offpeak rate and discharging it to meet consumption during the peak period.

✔ I’m in an apartment with no solar; is abattery any use to me?

You can install a battery (with strataapproval) to offset peak periodconsumption on a time of use tariff.Currently, this is unlikely to be an economicoption, even if you are on a time of usetariff. As an alternative, buying GreenPoweris a very easy way for apartment ownersto access renewable energy (see‘GreenPower’ on page 31).

✔ Will I benefit as a landlord?

If you already have solar or are thinkingof installing a home solar battery system,you have options to ensure that both youand your tenants get a financial benefit.10

There are no direct financial benefits thatare specific to installing batteries alone.However, adding a solar or solar batterysystem may make your property moreattractive to tenants and increase itsresale value.

✔ Which batteries are Australian made?

The majority of batteries are manufacturedoverseas, though there are some whichare developed by Australian companies.In recent years, several battery assemblyfacilities have established themselves inSouth Australia.


Section 8



✔ Will I have to go on a time of use tariff ifI install solar or a battery?

This depends on what tariffs your retaileroffers for your configuration, so be sureto check with them first. If you don’t thinkthe tariff you are currently on suits yourneeds, shop around. Visit Energy Switch,energyswitch.service.nsw.gov.au formore information.

✔ If I disconnect from the grid, will I stillhave to pay a daily service charge to thelocal grid?

There is currently no fixed network chargefor households that are disconnectedfrom the grid. However, disconnectingfrom the grid can incur fees and in mostcases disconnecting is unlikely to save youmoney even without a daily service charge.If you or a future owner want to reconnectthe property to the grid this will also incura cost.

✔ Can I use my rooftop solar energy tocharge an electric car?

In theory, battery electric vehicles can becharged solely from your rooftop solarenergy, but with the battery packs ofelectric cars ranging from 16 to 85 kWhor more, you would need a relativelylarge solar system with lots of sparecapacity to supply a full charge from solar.Your electric vehicle can be partially orfully charged from the grid to make upthe difference.

✔ I want to get an electric car eventually;can I use it to power my home too?

Depending on the charger type used inthe vehicle, some electric vehicle batteriescan be used to supply power to thehouse when they are not being used orrecharged. However, this is only offeredby a limited number of electric vehiclemanufacturers at present.

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https://energyswitch.service.nsw.gov.au/

Glossary

ACAlternating current—the form of electricity used in householdcircuits and on the grid

AEMO Australian Energy Market Operator

AS4777 The Australian Standard relating to solar and battery inverters

AS/NZS 5139 The Australian Standard for safe installation of battery systems

BMSBattery management system—software that regulates a battery’scharging and discharging cycle and other functions

CEC Clean Energy Council

Controlledload

Overnight ‘controlled load’ power is installed in many propertieson a separate circuit with a dedicated second meter. It is usedto provide cheap power to hot water systems, some pool pumpsand slab floor heating. Often called offpeak power, it should notbe confused with the offpeak rate on a time of use tariff, which isprovided via the main circuit

Cycle lifeThe number of times a battery can be discharged before reachingend-of-life. Note that what constitutes a full discharge is oftenpoorly defined

DCDirect current—the form of electricity produced by solar panelsand used in battery systems

DC to DCconverter

Steps the battery voltage back up to a nominal voltage that meetsthe requirements of the existing grid-interactive inverter

DoDDepth of discharge—the percentage of a battery’s usable capacitythat can be discharged from a battery without causing significantloss of storage capacity

EMSEnergy management system—software that interacts with thesolar system, inverter, home appliances and the grid to optimise abattery’s performance and value

Feed-in tariffPayment from your retailer (usually in cents per kilowatt-hour) foryour excess solar generation exported to the grid

Grid The electricity system, with poles and wires in your street


Section 8

HybridIn relation to inverters, means a solar plus battery inverter (not aninverter that is both ongrid and offgrid capable, as some peopleuse it)

Inverter

Device connecting your solar and/or battery system whichconverts DC (solar or battery) to AC (household) electricity. Ahybrid or multimode inverter connects to both the DC solar panelsand the battery

IP ratingIngress protection rating—determines whether battery is suitablefor indoor or outdoor installation; the higher the rating, the moreweather resistant it is11

kW Kilowatts—the instantaneous power output available to discharge

kWh Kilowatt hours—the total energy available to discharge

Lithium-ionThe most common battery chemistry. The most common varietiesare LNCM (lithium nickel cobalt manganese) and LiFePO4 (lithiumferrous phosphate)

Load profile

The energy usage pattern over a day or 24-hour period—it can becharacterised based on when energy is used the most—e.g. peaky(energy use is up and down through different parts of the day) orflat (relatively consistent usage throughout the day)

Meter

The device in your switchboard or meter box that measures theamount of electricity being imported to or exported from yourhouse. The main types are accumulation versus interval; grossversus net; and smart versus an older style. The optimum for asolar battery system is a smart meter, which will also be an intervaland a net meter. A solar battery system needs to be connected toa smart meter before it can be connected to the grid.

NetworkYour local distribution network service provider. In NSW this iseither Ausgrid, Endeavour Energy or Essential Energy

Nominalcapacity

The standard capacity designated by a battery manufacturer toidentify a particular battery cell model—may be 10–20 per centgreater than the usable capacity

Paybackperiod

The number of years it takes for the capital cost to be recoveredthrough lower energy bills

PV Photovoltaic solar panels

Glossary


RetailerThe company responsible for selling you electricity (and perhapsgas); also responsible for paying any feed-in tariff for excess solarenergy exported to the grid

RetrofittingInstallation of a battery where there is already an installed solarsystem. The term is generally used where something is added afterthe initial manufacturing or construction is complete

Roundtripefficiency

The ratio of a battery cell's output during discharge to its inputduring charge

Solar electrichot water

Electric hot water system heated by rooftop PV via the mainhousehold circuit—as distinct from solar thermal or heat pumphot water

Switchboard

A box or board containing switches, fuses or circuit breakers foreach electrical circuit in the home. This may be co-located with themeter in the meter box, or it may be separate, for example insidethe home

Smart meter

A smart meter (also known as a digital meter or ‘type 4’ meter) isa device that digitally measures when and how much electricity isused at your home. A smart meter sends this information back toyour energy retailer remotely, without your meter needing to bemanually read by a meter reader

STCsSmall-scale technology certificates—rebates available under thefederal Small-scale Renewable Energy Scheme for rooftop solarsystems (but not for batteries)

Three phasepower

Alternating current power supply using three instead of theusual single waveform, used to supply power to heavy loadssuch as electric vehicle fast charging, large power tools orindustrial equipment

TariffThe rates you are charged for electricity—usually flat (the samerate at any time) or time of use (with different rates for peak,shoulder and offpeak use) for households

UPSUninterruptable power supply, which has no lag time betweena grid power outage and the battery starting up (unlike otherbackup power systems, which may have a short time lag


Section 8

Australian batterycomparisonwebsites

Canstar Blue customer satisfaction researchwww.canstarblue.com.au/solar-power/list-of-solar-battery-retailers

National Distributed Energy Resource Registerwww.aemo.com.au/Electricity/National-Electricity-Market-NEM/DER-program/DER-Register-Implementation

Solar Quoteswww.solarquotes.com.au/solar-calculator

Battery technologyinformation

Educational website on all things batterywww.batteryuniversity.com

Business andindustrial customers

Energy Saver NSW for businesswww.energysaver.nsw.gov.au/business

Connectingto the grid

Endeavour Energywww.endeavourenergy.com.au > residential and business >network connections

Ausgridwww.ausgrid.com.au > connections > connectingembedded generation

Essential Energywww.essentialenergy.com.au > our network > connecting tothe network

Consumercomplaints

NSW Fair Tradingwww.fairtrading.nsw.gov.au

Energy & Water Ombudsman NSWwww.ewon.com.au

Where to go for moreinformation


http://www.canstarblue.com.au/solar-power/list-of-solar-battery-retailers

http://www.canstarblue.com.au/solar-power/list-of-solar-battery-retailers

http://www.aemo.com.au/Electricity/National-Electricity-Market-NEM/DER-program/DER-Register-Implementation

http://www.aemo.com.au/Electricity/National-Electricity-Market-NEM/DER-program/DER-Register-Implementation

https://www.solarquotes.com.au/solar-calculator/

http://www.batteryuniversity.com

http://www.energysaver.nsw.gov.au/business

http://www.endeavourenergy.com.au

http://www.ausgrid.com.au

http://www.essentialenergy.com.au

http://www.fairtrading.nsw.gov.au

http://www.ewon.com.au

Consumer guidesand information

Clean Energy Council website on buying battery storagewww.cleanenergycouncil.org.au/consumers/buying-battery-storage

Clean Energy Council Guide to Installing A Household

Battery Storage System (2019)assets.cleanenergycouncil.org.au/documents/consumers/battery-storage-guide-for-consumers.pdf

Choice How to buy the best solar battery storagewww.choice.com.au/home-improvement/energy-saving/solar/buying-guides/battery-storage-buying-guide#types

Installeraccreditation

Clean Energy Council accredited installer listwww.cleanenergycouncil.org.au/consumers/buying-solar/find-an-installer

Meters

Energy NSW smart metersenergysaver.nsw.gov.au/households/understand-your-usage/smart-meters

Energy NSW factsheet and FAQsenergysaver.nsw.gov.au/media/1456/download

NSW Home SolarBattery Guide

Energy NSWenergysaver.nsw.gov.au/solar-battery-systems

Offers and tips tohelp reduce yourenergy use

Energy Saver NSWenergysaver.nsw.gov.au


Section 8



https://assets.cleanenergycouncil.org.au/documents/consumers/battery-storage-guide-for-consumers.pdf

https://assets.cleanenergycouncil.org.au/documents/consumers/battery-storage-guide-for-consumers.pdf

https://www.choice.com.au/home-improvement/energy-saving/solar/buying-guides/battery-storage-buying-guide#types

https://www.choice.com.au/home-improvement/energy-saving/solar/buying-guides/battery-storage-buying-guide#types



https://energysaver.nsw.gov.au/households/understand-your-usage/smart-meters

https://energysaver.nsw.gov.au/households/understand-your-usage/smart-meters

https://energysaver.nsw.gov.au/media/1456/download


https://energysaver.nsw.gov.au/

Recycling anddisposal

Australian Battery Recycling Initiativebatteryrecycling.org.au/recycling/energy-storage-batteries

CSIRO lithium-ion battery recycling reportwww.csiro.au/en/Research/EF/Areas/Grids-and-storage/Energy-storage/Battery-recycling

SafetyClean Energy Councilwww.cleanenergycouncil.org.au/industry/products/batteries/battery-safety-guide

Sizing and pricingcalculators

Renew basic solar and battery advice calculatorwww.renew.org.au/free-solar-and-battery-advice

Renew Sunulator solar feasibility calculator in MS Excelwww.renew.org.au/resources/sunulator

Solar Choice online battery calculatorwww.solarchoice.net.au/blog/solar-pv-battery-storage-sizing-payback-calculator

The NSW Government does not fact check or endorse these calculators.

Solar panels

Energy Saver website about installation and connection of

solar panelsenergysaver.nsw.gov.au/households/solar-and-battery-power/installing-and-connecting-solar-panels

Tariff comparison

Energy Made Easywww.energymadeeasy.gov.au

Energy Switchenergyswitch.service.nsw.gov.au

IPART NSW solar feed-in tariff informationwww.ipart.nsw.gov.au/Home/Industries/Energy/Reviews/Electricity/Solar-feed-in-tariffs-201920

Where to go for moreinformation


https://batteryrecycling.org.au/battery-types/energy-storage-batteries/

https://www.csiro.au/en/Research/EF/Areas/Grids-and-storage/Energy-storage/Battery-recycling

https://www.csiro.au/en/Research/EF/Areas/Grids-and-storage/Energy-storage/Battery-recycling

https://www.cleanenergycouncil.org.au/industry/products/batteries/battery-safety-guide

https://www.cleanenergycouncil.org.au/industry/products/batteries/battery-safety-guide

http://www.renew.org.au/free-solar-and-battery-advice

http://www.renew.org.au/resources/sunulator

http://www.solarchoice.net.au/blog/solar-pv-battery-storage-sizing-payback-calculator

http://www.solarchoice.net.au/blog/solar-pv-battery-storage-sizing-payback-calculator

http://energysaver.nsw.gov.au/households/solar-and-battery-power/installing-and-connecting-solar-panels

http://energysaver.nsw.gov.au/households/solar-and-battery-power/installing-and-connecting-solar-panels

http://energyswitch.service.nsw.gov.au

http://www.ipart.nsw.gov.au/Home/Industries/Energy/Reviews/Electricity/Solar-feed-in-tariffs-201920

http://www.ipart.nsw.gov.au/Home/Industries/Energy/Reviews/Electricity/Solar-feed-in-tariffs-201920

NSW government has a lot of informationavailable, make sure you do yourresearch before making a decision to getthe best results for your situation.


Section 8

Modelling assumptionsITP modelled the scenarios summarised in Figure 10 on page 35 of the guide and describedin detail in the five practical examples. This work was conducted in January 2020 usingITP’s knowledge of current market prices for electricity, solar PV and battery energy storagesystems. Further assumptions are provided below.

• Network electricity tariffs are standardmidrange flat or time-of-use offers for theselected locations.

• Solar panels were assumed to benorth-facing and tilted at 20 degreesabove horizontal. The system was assumedto be operating at a performance ratioof 80 per cent.

• HOMER Pro simulates solar generationfor each interval based on horizontalirradiance data, the angle between the sunand the solar panels, and the performanceratio. For this modelling, irradiance datawas downloaded from the AtmosphericScience Data Centre at NASA’s LangleyResearch Center.


• An energy balance is conducted for eachhour of the simulation by considering theprevailing load and solar generation, withthe battery then charging or dischargingso as to minimise grid import and export.

• Import and export tariffs are applied to thenet load, depending on the prevailing tarifffor that hour of the simulation.

• A small cost was assumed for the annualoperation and maintenance. This cost wascalculated as 0.5 per cent of the estimatedcapital cost.

• Component replacement wasnot modelled.

• Gird-connected battery systems wereassumed to have a round-trip efficiency of88 per cent. Offgrid battery systems wereassumed to have a round trip efficiencyof 80 per cent. The useable capacity waslimited to 70 or 80 per cent of the initialnominal capacity (depending on thewarranty conditions of the battery systemassumed for the scenario). Degradation ofthe usable capacity was not modelled.


Section 8

Notes and references1. Clean Energy Regulator via www.cleanenergyregulator.gov.au

2. Energy consumption breakdown based on June 2017analysis by the NSW Office of Environment and Heritagefor a Western Sydney household using electricity for hotwater heating and space heating.

3. See www.energyrating.gov.au

4. See www.renew.org.au/articles/energy-flows-how-green-is-my-solar

5. That is, the battery will pay for itself within the warrantyperiod and will save money compared to network importsover the same period. However, solar-only may still providea superior return on investment.

6. There are battery chemistries requiring regularmaintenance such as weekly discharging, but this is oftendone automatically, and lithium-ion is not among them.

7. You can tell by checking the IP or ingress protection rating,which combines measurements for resistance to dust andmoisture. It should be 55 or above, and preferably 67, forexternal installation. See www.batteryjunction.com/ip-rating-guide.html for more detail.

8. Habitable rooms include a bedroom, living, lounge anddining room. A full list of what is considered a habitableroom can be found in the Building Code of Australia.

9. For more details, refer to manufacturers’ recommendationsand the Clean Energy Council battery installation guide.

10. Usually you can provide the energy to your tenants inreturn for a slightly higher weekly rent without a change inthe metering. However, if you have more than one tenantthe wiring and metering will need to be set up to ensurethan all tenants receive the solar and battery energy. Oryou may be able to sell the energy to them by changingthe wiring and meters so there is a main or ‘parent’ meterfor the entire premises and create an embedded network.If you look at this option you should contact the AustralianEnergy Regulator as you may need to obtain approvalto operate as an ‘exempt retailer’: www.aer.gov.au/retail-markets/retail-exemptions. There may be taxation benefits,as solar and batteries are capital improvements that can beoffset against rental income.

11. See www.batteryjunction.com/ip-rating-guide.html formore detail.


http://www.cleanenergyregulator.gov.au

http://www.energyrating.gov.au

http://www.renew.org.au/articles/energy-flows-how-green-is-my-solar

http://www.renew.org.au/articles/energy-flows-how-green-is-my-solar

http://www.batteryjunction.com/ip-rating-guide.html


http://www.aer.gov.au/retail-markets/retail-exemptions

http://www.aer.gov.au/retail-markets/retail-exemptions



Section 8

NSW Home Solar Battery Guide

Published by NSW Department of Planning, Industry and Environment

dpie.nsw.gov.au

First published: April 2020

© State of New South Wales through Department of Planning, Industry and Environment 2020.

This publication is copyright. You may download, display, print and reproduce this material provided that the wording is reproducedexactly, the source is acknowledged, and the copyright, update address and disclaimer notice are retained.

Disclaimer: The information contained in this publication is based on knowledge and understanding at the time of writing (April 2020)and may not be accurate, current or complete. The State of New South Wales (including the Department of Planning, Industry andEnvironment), the author and the publisher take no responsibility, and will accept no liability, for the accuracy, currency, reliability orcorrectness of any information included in the document (including material provided by third parties). Readers should make theirown inquiries and rely on their own advice when making decisions related to material contained in this publication.

http://dpie.nsw.gov.au

nsw home solar battery guide

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