© 2018 Austin Energy

DER IntegrationBridging the Operations/Program Divide

November 12, 2018

Peak Load Management AllianceInterest Group Meeting

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Agenda

01 Background

02 What is DER Integration?

03 Austin Energy Experience

04 DER System Impacts

05 Breakouts

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L I S A M A R T I ND E R I N T E G R A T I O N

A U S T I N E N E R G Y

A B O U T T H E P R E S E N T E R

Lisa Martin is a Program Manager of Advanced Technology at Austin

Energy. Her focus is in the field of Distributed Energy Resource (DER)

Integration.

Lisa serves as the project manager for Austin SHINES, a federal and

state-funded project that establishes an open standards-based DER

management platform to integrate and optimize DER at several

levels along the utility value chain. Lisa has a BS in Electrical

Engineering and an MBA in Operations Management. She is a

registered Professional Engineer in the State of Texas.

BRIEFBIO

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About Austin EnergyPublic Power• 2nd largest municipally owned utility in Texas• Reports to the City Manager, who executes the policy and direction

of the City Council• 1700+ Employees

Compact, Dense System• 437 square miles of service area covering

City of Austin and beyond• 491,000+ meters (65,000+ C&I)

Vertically-Integrated• Vertically-integrated in a deregulated, wholesale, energy only market• 2018 AE System Peak Load 2878 MW (summer), 2381 MW (winter)

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Offset 65% of customer load with

renewable resources

Austin Energy 2027 Goals

1000 MW of savings from

energy efficiency and demand

response

750 MW utility-scale solar + 200 MW local solar,

including 100 MW customer-sited PV

10 MW battery storage and 20 MW thermal

energy storage

Net zero community-wide GHG emissions by

2050

All subject to meeting Affordability Goals: <2% rate increase per year; Austin Energy rates in lower 50th percentile of statewide utilities

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Enriching the lives of our customers and communities by being their trusted energy Provider, Platform, and Partner

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Distributed Energy Resource (DER) IntegrationThe study of how to interconnect distributed resources and controllable loads into our grid

For customers and the utility this value may looking like• Energy self-supply• Sustainability• Emergent technology• Bill savings• Back-up power capabilities• Grid services• And more…

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Asset Types

=~

DC

AC

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Technology Communications & Control Market

Leveraging Customer-sited Assets to Solve Circuit-level IssuesSame Topic, Three Perspectives during Breakout Sessions

How will technology evolve in the world around us?

How can traditional and new asset types be leveraged to address emerging problems?

What communications pathways/protocols, telemetry requirements, and data integration/

assimilation needs exist?

How will the assets become part of a coordinated system?

How will they be optimized?

What business models will engage the market?

Who are the players and what partnerships/ coordination efforts need to take place?

What incentives/rates/settlements play a part?

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DER at Austin Energy

Solar PV Palmer Events CenterBattery Storage KB ESS, MU ESSDistributed Generation RMEC

OwnSolar 466 MWWind 1219 MWBiomass 107 MW

ContractIncentives and programs for

Demand ResponseElectric VehiclesControllable Loads

Partner

Do we drive DER penetration, accommodate it, or react to it?

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Austin SHINES Concept

Utility Scale Energy Storage + PV

Commercial Energy Storage + PV

Residential Energy Storage + PV

DER Management Platform

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Utility ScaleLa Loma Community Solar

•2.6 MW Photovoltaic solarKingsbery Energy Storage System

•1.5 MW / 3 MWh Li-Ion battery storageMueller Energy Storage System

•1.75 MW / 3.2 MWh Li-Ion battery storage7 Energy Storage Units (250 kW each)

Austin SHINES Assets

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Commercial ScaleAggregated Storage Installations at 3 sites, with existing solar (300+ kW)

•One 18 kW / 36 kWh Li-Ion battery storage•Two 72 kW / 144 kWh Li-Ion battery storage

Residential ScaleAggregated Storage Installations

•Six stationary battery storage systems (10 kWh each) at homes with existing solar

•One Electric Vehicle installed as Vehicle-to-Grid (V2G)

Utility-Controlled Solar via Smart Inverters at 12 homesAutonomously-Controlled Smart Inverters at 6 homes

Austin SHINES Assets

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DER Management System, DG-DEROTM

Fleet-wide controller at T&D control center & energy market desk

Circuit-level control for applications like voltage control

Works with site-level controller or aggregator for field installations

Inputs include grid data, market data and forecasts (weather, load, & price)Distributed Energy Resource Optimizer

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DERO in an Austin Energy Ecosystem

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DR CapabilitiesPeak Load Reduction

for economic or reliability purposes

How can you put more tools in the DR toolbox?

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University of Texas ResearchHighlighting Energetic and Economic Potential for Load Control for

Residential Customers in Austin, Texas

Determine maximum possible peak load (kW) reduction & shifts in total consumption (kWh) by considering operational changes to rooftop solar PV, energy storage systems

(batteries), HVAC, electric vehicles, electric water heaters and pool pumps

©Bandyopadhyay et al, 2018

Arkasama Bandyopadhyay, Julia P. Conger, Michael E. Webber

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A load shifting algorithm is applied to the overall load

profile for each appliance to reduce peak demand(Sinha and De, 2016)

©Bandyopadhyay et al, 2018

Priority1. HVAC2. Electric WH3. EV4. Pool Pump

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Issue: Reverse Power Flow

Objective: Consume Power/Shift Load

Issue: Exceeding Thermal Limits

Objective: Congestion Management

1 2

3 4

Issue: Lower System Inertia

Objective: Frequency Support

Issue: Voltage Volatility

Objective: Voltage Support

System Impacts from High DER Penetration

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System Inertia and Frequency

Power grid stability exists when

Supply = DemandGeneration = Load

1

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System Frequency•System frequency is related to

rotational equipment on the grid

• It must remain within a tight tolerance band for the system to remain stable

•Frequency depends on the real power balance, supply and demandRevolutions Per

Minute (RPM)Frequency = cycles/sec

orHertz [Hz]

GENERATOR

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System Frequency•When supply = demand, the

rotating machinery is spinning at a certain rate• When supply and demand get out of

balance, the rotating machinery must either speed up or slow down to compensate

• The rate at which the machinery spins changes, meaning its frequency changesRevolutions Per

Minute (RPM)Frequency = cycles/sec

orHertz [Hz]

GENERATOR

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System Inertia and Frequency

• If generation and load are not balanced, system frequency will change at a rate initially determined by the inertia of the entire system

•Systems with higher inertia are not as affected by a change in the generation/load balance

•That is, inertia sets the rate at which frequency falls after a generator trips offline

Objects at rest tend to stay at rest and objects in motion tend to stay in motion (unless acted on by an outside force)

Law of Inertia:

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Dr. Ning Lu, North Carolina State University

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Impact of Renewables on System Inertia

• In robust systems (higher inertia), system frequency is less sensitive to power imbalances

•But, when more and more renewables are added, system inertia drops

•That is, the system frequency becomes more susceptible to power imbalances

Dr. Ning Lu, North Carolina State University

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Generation Trips OfflineDemand >> SupplyFrequency Drops

Traditional response:

• Generator governors work to cause online generation to ramp up and compensate for lost supply

• If not done quickly enough, UFLS will cause load to drop offline to compensate for excess demand

What can DR do to play a part in the solution?

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Solar Irradiance, Temperature and Voltage Volatility

Power grid stability exists when

Voltage is stable

2

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System Voltage• Photon current, Iph, is dependent upon

the irradiance available at a certain time and location

• If the amount of sunlight on the panel decreases, there is less photon current which would ultimately lead to less output current, I

• As current changes, so does voltageIdeal model of a solar cell

G = irradiance or sunlight intensity, [W/m2]

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https://www.ecmweb.com/green-building/highs-and-lows-photovoltaic-system-calculations

Irradiance impacts on a solar module’s current and voltage curve

Irradiance Impacts on System Voltage

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https://www.ecmweb.com/green-building/highs-and-lows-photovoltaic-system-calculations

Temperature impacts on a solar module’s current and voltage curve

• Temperature changes also impact a solar module’s current and voltage curve

• For a given current (e.g., irradiance is steady) voltage varies by temperature

Temperature Impacts on System Voltage

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Impact of Renewables on System Voltage

•A change in the voltage output may not seem significantly large for a single panel, but as the number of panels increase, the voltage fluctuations increase and it becomes detectable on the distribution level

•Voltage volatility leads to instability which can impact residential and commercial appliances as well as grid-level protection devices and equipment

•We need to maintain voltage in certain tolerance bands, often nominal +/- 5%

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Voltage Support• We often think of smart inverters to

remedy this fix• Can use the inverter for PV or battery

storage to provide voltage support

• Most common method, Volt-VAR

• But what about Volt-Watt?• As load increases, voltage drops• As load decreases, voltage rises

When is Volt-Watt most effective, and what can DR do

to be part of the solution?

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Reverse Power Flow• When rooftop photovoltaic (PV) systems

are connected to the distribution network, local load initially consumes the power produced

• Excess power is used for charging battery storage or flows back to the grid

https://www.befutureready.com/ezine-article/making-way-two-way-power-flows-planning-control-matters/

3

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Detecting Reverse Power Flow•Reverse power flow can be detected by looking at voltage and current

waveforms

•Or by looking at current flowing from the substation

https://web.wpi.edu/Pubs/E-project/Available/E-project-122215-204620/unrestricted/MQP_Final_Report.pdf

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Reverse Power Flow

Impacts:

• Overloading of distribution lines or transformers

• Entry into the substation … transmission level impacts

• Unstable operation of protective equipment• Generally designed for one-way power flow

What can DR do to consume or shift load to offset reverse

power flow conditions?

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Thermal Overloads• Overloading of lines or equipment is not

necessarily due to high DER penetration

• Still, there is an opportunity for DER to provide value by matching supply and demand locally and relieving overloaded equipment

• Energy storage can provide congestion management• Discharging helps if it can be used to meet local needs• If excess flow on a line, storage can charge (to use that

supply) and prevent overloads further downstream??

4

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Thermal Overloads• Overloading of lines or equipment is not

necessarily due to high DER penetration

How can you use DR to relieve congestion?

How can behind-the-meter loads become aware of congestion so they can remove

themselves from the equation?

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Your goal is to think about DR differently. How can you take the thoughts we’ve just discussed and expand your view of DR and the value it can offer?

DER integration is not about individual assets operating in silos. It’s about using all the tools in your toolbox to create

the right customer experience the full business case a safe, reliable, affordable power system the holistic solution …

©2018 Austin Energy. All rights reserved. Austin Energy and the Austin Energy logo and combinations thereof are trademarks of Austin Energy, the electric department of the City of Austin, Texas. Other names are for informational purposes only and may be trademarks of their respective owners.

Thank you!

Lisa Martin

Lisa.Martin@austinenergy.com

40

Technology Communications & Control Market

Leveraging Customer-sited Assets to Solve Circuit-level IssuesSame Topic, Three Perspectives during Breakout Sessions

How will technology evolve in the world around us?

How can traditional and new asset types be leveraged to address emerging problems?

What communications pathways/protocols, telemetry requirements, and data integration/

assimilation needs exist?

How will the assets become part of a coordinated system?

How will they be optimized?

What business models will engage the market?

Who are the players and what partnerships/ coordination efforts need to take place?

What incentives/rates/settlements play a part?