powered by the sun

POWERED BY THE SUNAlex Moundalexis

@technmsg

Slides: github.com/technmsg/sun-powered

CC BY 4.0

WHY ME?18 months w/ solar panels

practical knowledge

computery guy by training and trade

WHY PEOPLE CHOOSE SOLAR?reduce dependency on non-renewables

reduce utility bills

insulate against future energy costs

increase home resale value

cool factor

SOLAR PV 101

RESIDENTIAL PV SYSTEM

0. SUNLIGHT

the sun delivers more energy to Earth in one hour thanhumanity consumes over the course of a year

-- MIT Technology Review

1. SOLAR PV MODULES

Photovoltaics is the direct conversion of light intoelectricity at the atomic level.

-- NASA

remember solar calculators?

ever notice that old ones get flaky?

Photons strike and ionize semiconductor material on thesolar panel, causing outer electrons to break free of their

atomic bonds. -- Solar Energy Industries Association

solar panel output degrade over time

most manufacturers warrant ~80% of rated power a�er 25 years

2. INVERTER

converts direct current (DC) into alternating current (AC)

(apologies to Nikola Tesla)

2A. PRODUCTION METER

measures what the system produces

3. FUSEBOX

backfeeding

bus bars don't care about the source of power

4. BATTERY (OPTIONAL)

expensive

heavy

maintenance

5. METER

by default, meters measure absolute usage

net metering

6. GRID

ACQUISITION

PURCHASEyou own it

all the incentives

cash up front / special loans

LEASE / PPAvendor-owned

buy power per-kWh

typically zero down

no incentives

COMMUNITY SOLARshared roo�ops & spaces

shared costs

shared incentives

co-op style

PICKING A VENDORshop around

savings calculations (kWh)

3rd party contractors

reputation

local presence

PAPERWORK

INSPECTIONroof: dimensions, orientation, gotchas

attic: truss spacing

electrical: panel

SYSTEM DESIGNCAD drawing

power output report: accounts for dimensions, orientation, roof pitch, shade,time of year

INTERCONNECTnotifies utility of intent to generate power

proper billing

safety for utility workers

INCENTIVESfederal / state / local

grants

tax credits

www.dsireusa.org

HOA APPROVALSsolar easements and rights laws

(tedious)

SREC REGISTRATIONSolar Renewable Energy Credit

1 MW = 1 credit

commodity market

typically sold via aggregator to utilities

EXAMPLE SYSTEM #116 SunPower panels

SunPower inverter

3.92 kW

purchase

17,000 USD

EXAMPLE SYSTEM #224 Yingli panels

SolarEdge inverter

6.63 kW

20 year PPA @ 11.3¢/kWh

zero down

EXAMPLE SYSTEM #320 unknown panels

unknown inverter

6.25 kW

20 year PPA @ 6.1¢/kWh

7300 USD pre-paid in full

INSTALLATION DAY

BEFORE

DURING

AFTER

ACTIVATION

waiting...

for a County inspector to check structure & electrical

for the power company to install the net meter

(anticlimactic)

BREAK?

IMPACT

DAILYwith net metering, usage unchanged

most days production > usage

w/o net metering, migrate demanding tasks to daytime

Energy Produced on 2 May 2016

MONTHLYproduction varies by season

no maintenance required

Energy Products in 2015

LONG TERM12 months in...

85% of my electrical needs

50% expenses recouped

payoff expected in 5-6 years

MONITORING

Dashboard

GAMIFICATIONinevitable, given data

measure everything

minimize usage

DAILY USAGE

BIG USES2 kWh - fridge

2 kWh - always-only Internet**** fiber ONT, router, UPS, two wireless routers, Chromecast, VOiP bridge, VOiP handsets, core switch

LIGHTINGlargely overlooked

inefficient incandescent

3-way bulb > entertainment center

ELECTRONICSmost modern electronics are wildly efficient

1 kWh - 8 hrs WFH: laptop, monitor, speakers

¼ kWh - stream a movie on home theater

STANDBY CONSUMPTION

INKJET PRINTER1.4W standby

0.1W powered off

DELL FLAT-PANEL35-45W in operation

3.7W standby

3.6W powered off

DOWNSIZING

HOME SERVERDell PowerEdge SC 440

100W = 72 kWh/month = $9.36

vs

Raspberry Pi B+

1.6W = 1.5 kWh/month = 20¢

(ENERGY) PRODUCTION DATAREST API

web scraping

to automate browser activitySelenium

ENPHASE

The allows mobile apps, buildingmanagement tools and other so�ware applications to

access and use system performance data. --

Enlighten API

Enphase Support

SOLARCITY

The PowerGuide API is a RESTful service that can beinvoked from any HTTP client, and allows you to query

PowerGuide Data. -- PowerGuide API documentation

SUNPOWER

The API was developed for our flex applications and thereare no plans to make it available to 3rd party developers.

-- @sunpower

CSVInterval Start Date,Energy (kWh) 2016-05-14T05:00:00,0 2016-05-14T06:00:00,0.040 2016-05-14T07:00:00,0.160 2016-05-14T08:00:00,0.270 2016-05-14T09:00:00,0.390 2016-05-14T10:00:00,0.930 2016-05-14T11:00:00,1.440 2016-05-14T12:00:00,1.530 2016-05-14T13:00:00,2.780 2016-05-14T14:00:00,0.810

SPECIAL THANKSFreedom Solar Power

SunPower

(show and tell goodies)

MORE WORDSBlog: Going Solar

bit.ly/v2-solar

Get solar (via SunPower)

bit.ly/get-solar

Slides

github.com/technmsg/sun-powered

THANKSAlex Moundalexis

@technmsg