2018-05-08

1

Distributed Energy Resourcean AESO Perspective

Steve Heidt P. Eng.,

AESO

About the AESO

• Grid planner and

operator – reliability is

our highest priority

• Connects new

generation and load

• Facilitates wholesale

electricity market

• Operates Renewable

Electricity Program

(REP) to achieve ‘30 by

30’ green energy goal

202/21/2018 Public

2018-05-08

2

Snapshot: Alberta’s power system

3

• High industrial load

• 26,000+ km of transmission

• ~240 generating units

• ~650 substations

• 16,346 MW installed generation

– 11,697 MW winter peak (Jan. 11/18)

• Strong transmission system to

support competitive wholesale

power market

• ~200 projects active in AESO

connection queue

02/21/2018 Public

Evolving generation mix – transition

from coal to gas/renewables

By 2037:

• Coal ↓ 6,299 MW

• Cogen ↑ 405 MW

• Gas-fired ↑ 6,658 MW

• Coal-to-gas ↑ 790 MW

• Renewables ↑ 6,350 MW

402/21/2018 Public

2018-05-08

3

Transmission Operation Basics

• Energy Balance Equation

– Main rule is that Supply = Demand

– Generation + Import = Load + Losses + Exports

• Short on Supply => reduction in speed (or import through a AC

Tie)

• Conventional Generation are Electro-Mechanically coupled

to the Grid

– Large Mass generators spinning at grid frequency

– System inertia

5

Example: Frequency Response

6Source: https://www.ferc.gov/industries/electric/indus-act/reliability/frequencyresponsemetrics-report.pdf

Disturbance

Inertial Response

Frequency Nadir

Primary Frequency

Response

2018-05-08

4

DER

• Wind, Solar and Battery Storage resources are Electronically

Coupled to the grid

– Inverters have a very fast electronics (DC to AC)

– This is a Digital Revolution in power generation, with the ability

to program the behaviors we need … But we need to fully

understand exactly what we want

7

Definition of REVOLUTION

– a sudden, radical, or complete change

– activity or movement designed to effect fundamental changes

in the socioeconomic situation

– a fundamental change in the way of thinking about or

visualizing something

– a changeover in use or preference especially in technology ie.

the computer revolution, the foreign car revolution..

• Maybe a Power System Revolution…

• Mainly thanks to Power Electronics

From a Nikola Tesla Model => Sustainability Model

Source: Merrian-Webster Dictionary8

2018-05-08

5

DER - Definitions

• NERC Definition

– A Distributed Energy Resource (DER) is any resource on the

distribution system that produces electricity and is not

otherwise included in the formal NERC definition of the Bulk

Electric System (BES).

• In Alberta (Informal)

– Distributed Energy Resource (DER) is any resource on the

distribution system that produces electricity

– Resources greater than 5 MW are Pool Participants

• Bound by some Rules and Standards

9

Help from industry

• Germany Experience

– Renewables went from 6% to 31% in 15 years

• Industry on DER

– IEEE 1547 – Interconnection and Interoperability of Distributed

Energy Resources with Associated Electric Power Systems

Interfaces (April 2018)

– 2003 DER shall not actively regulate the voltage

– 2014 DER may actively participate to regulate the voltage by

changes of real and reactive power

– 2018 DER shall provide voltage regulation capability by

changes of active and reactive power

• AESO is using this as a guide

10

2018-05-08

6

Could DER cause Reliability Concerns?

• It's possible, if you're not prepared!

• In mid 2017 there was 475 MW on Alberta’s system

– Have not seen concerns at that level … so far

– But when will we have concerns/troubles?

11

Could DER cause Reliability Concerns?

• It's possible, if you're not prepared!

• In mid 2017 there was 475 MW on Alberta’s system

– Have not seen concerns at that level … so far

– But when will we have concerns/troubles?

• How about this for a test..

– What would you see if you had a 12,000 MW system with

6,000 MW of DER? (this is not a forecast – It’s a test)

– What concerns show up?

12

2018-05-08

7

Thinking your way through it?

• Supply adequacy & Forecasts

– Where are the DERs?

– What their’s fuel type?

• Wind, Solar, Gas, Battery, Other

– What is their pattern of generation levels?

– Where are they connected to (which Substation / Area)?

– What is their ride through capability?

– What happens during a Solar Eclipse / Storms / Holidays?

13

Thinking your way through it?

• Supply adequacy & Forecasts

– Where are the DERs?

– What their’s fuel type?

• Wind, Solar, Gas, Battery, Other

– What is their pattern of generation levels?

– Where are they connected to (which Substation / Area)?

– What is their ride through capability?

– What happens during a Solar Eclipse / Storms / Holidays?

• We need good data and be able to forecast.

14

2018-05-08

8

CAISO’s “Duck Curve”

– California’s version of NDV Daily Curve

Net Demand = Load Demand – Variable Generation

In California the variable generation is mainly solar generation

15

18,000

19,000

20,000

21,000

22,000

23,000

24,000

25,000

26,000

27,000

28,000

29,000

30,000

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

MW

Average of CAISO's Load for 5 Consecutive weekdays --- 2008 VS. 2018

CAISO Load 2008 CAISO Load 2018

Pa

ge

1

Actual California Spring “Gross Load” March 2008 vs. March 2018

2018-05-08

9

Thinking your way through it

• What is our true system load?

• How are DER generating now?

• How are DER offsetting distribution load?

• Will this effect our Operation Reserves?

• How do we know if our forecasts on DER is close?

• Do we have enough supply adequacy?

17

Thinking your way through it

• What is our true system load?

• How are DER generating now?

• How are DER offsetting distribution load?

• Will this effect our Operation Reserves?

• How do we know if our forecasts on DER is close?

• Do we have enough supply adequacy?

• We need Real Time Visibility

– > 1MW (projected)

– Grouped by fuel class and

– Feeder Substation or Area18

2018-05-08

10

Thinking your way through it

• How does DER effect System events

– Frequency Events

– Voltage events

– Older Technical standards like IEEE 1547 says

• Must trip or may ride through

19

Thinking your way through it

• How does DER effect System events

– Frequency Events

– Voltage events

– Older Technical standards like IEEE 1547 says

• Must trip or may ride through

– We need ISO Rules

• Defined Criteria for

– Must Ride through

– May trip

• Revised IEEE 1547 outline industry expectations

20

2018-05-08

11

Thinking your way through it

• Tariff

– Cost causation

– DER pay for their part of transmission costs

• Transmission Remedial Actions Schemes

– In a transmission constrained area should DER be RAS(s)?

• Governor Controls

– Under and Over Frequency

• Power Limiting Controls

– Direct down Capability

21

Thinking your way through it

• DER Metering / Settlement Information

– Rules and Modification outlining settlement changes?

• Market Rules and the applicability to DER

– Does the Market need modifications?

– Should the Must offer/must comply change?

• Planned / unintentional Islanding (and anti-islanding) for

Transmission Events

– Transmission Based Islanding standards?

22

2018-05-08

12

DFO rules

• Technical Rules

– Controllability (Dispatch Down or off)

• ISO needs this too

– Voltage Control, Voltage Regulation

• Reactive Power Capability and reactive power control

• AVR like controls

– Volt-Var Control

– Volt-Watt Control

– Planned / unintentional Islanding (and anti-islanding) for

distribution events

23Draft - Subject to change

Industry Background

• The ISO

– Direct/obligate pool participants in accordance with ISO rules.

(Generators that are >5MW, TFOs, and DFOs)

– Direct the DFOs to manage DERs that are not pool

participants to manage transmission reliability.

• DFO manages/directs distribution reliability

• For all other future ISO requirements

– the ISO would obligate the DFO who in turn would enforce

these requirements onto DER owners.

24

2018-05-08

13

Thank you