Conseptualizing Flexibility In Power

Systems21st Century Power Partnership:

An Initiative of the Clean Energy Ministerial

Dr. Douglas Arent

National Renewable Energy Laboratory

Operating Agent for the 21CPP

India (co-lead)

Denmark Finland Mexico(co-lead)

South Africa Spain United States(co-lead, under review)

Brazil China

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THOUGHT LEADERSHIPSTUDIES

Flexible Coal Evolution from Baseload to Peaking Plant. December 2013

Wholesale Electricity Market Design for 21st Century Systems. October 2013

Accelerating the Global Transition to 21st Century Power Systems. July 2013

The Role of Demand Side Management in the Utility of the Future. April 2014.

The Evolving Role of the Power Sector Regulator. April 2014.

Flexibility in 21st Century Power Systems. May 2014.

Overview of Variable Renewable Energy Regulatory Issues. May 2014.

Power Systems of the Future. February 2015.

Status Report on Power System Transformation. May 2015.

Clean Restructuring: Design Elements for Low Carbon Wholesale Markets. May 2015.

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Sources of Flexibility

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HOW MUCH FLEXIBILITY CAN BE

EXTRACTED FROM LARGE, FAST

ENERGY MARKETS?

Milligan, Kirby, King, Beuning (2011), The Impact of Alternative Dispatch Intervals on Operating Reserve Requirements for Variable Generation. Presented at 10th International Workshop on Large-Scale Integration of Wind (and Solar) Power into Power Systems, Aarhus, Denmark. October

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

Footprint Regional BAU

Aver

age

Tota

l Reg

ulat

ion

(MW

)Average Total Regulation for 6 Dispatch/Lead Schedules by Aggegation (Dispatch interval -

Forecast lead time)

10-10

30-10

30-30

60-10

30-40

60-40

Faster Faster Faster

Large Medium Small

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Timescale of flexibility Type of flexibility How variable RE provides this

Sub-second Autonomously generated: synthetic inertia

Fast frequency response with a power electronic converter

Seconds Autonomously generated: synthetic governor response

Slower frequency response through electronic governor

Minutes Remotely operated: automatic generation control

Market or system operatorinclusion in ancillary services

Minutes to hour Economic dispatch Market or system operator inclusion in dispatch

Day Scheduling (unit commitment)

Market or system operator inclusion in day-ahead scheduling

6Services from

Variable RE

Source: Milligan et al 2015

Evolving characteristics of wind and solar

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Evolving characteristics of wind and solar

Characteristic Old New

Dispatchability Uncontrollable, “must-take”

Dispatchable through participation in economic dispatch

Forecast/uncertainty Unpredictable Increasingly forecastable

Variability Highly variable over multiple timescales

Very short-term variability largely mitigated via spatial diversity

Reserve requirements Requires dramatic increase in operating reserves from thermal units

Relatively small increase in regulation required. Can self-provide multiple reserves across multiple timescales with selective/economic curtailment

Grid support Provides no grid support/decreases grid stability

Can provide multiple grid support services

7Services from

Variable RE

Source: Milligan et al 2015

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PV Power Auto Generation Control

• Thin-film Cd-Te PV modules

• 4 MVA PV inverters

• 9 x 40 MVA blocks

• 34.5 kV collector system

• Two 170 MVA transformers

• Tie with 230 kV transmission line

• PMUs collecting data on 230 kV side

• 4-sec AGC signal provided to PPC

• 30 MW headroom

• Tests were conducted at three resource intensity conditions

• 1-sec data collected by plant PPC

Case Study: CAISO & PJM

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CAISO1. Day Ahead Market2. Real Time Market

• 15 and 5 minute dispatch3. Ancillary Services Markets

• Regulation Up• Regulation Down• Spinning• Non Spinning

4. Congestion Rights5. Convergence Bidding6. Energy Imbalance Market

PJM1. Energy2. Capacity

• 3 years to 3 months• Gen, EE, DR & Tx

3. Regulation4. Reserves5. Reactive Voltage and Frequency6. Black Start7. Demand Response

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CHARACTERISTICS THAT

HELP INTEGRATION

Large BA

Geographically Dispersed Wind and Solar

Wind/Solar Forecasting Effectively Integrated Into System Operations

Sub-Hourly Energy Markets

Fast Access to Neighboring Markets

NonSpinning and 30 Minute Reserves for Wind/Solar Event Response

Regional Transmission Planning For Economics and Reliability

Robust Electrical Grid

More Flexible Transmission Service

Flexibility in Generation

Responsive Load

Overall

Example Utility Structures

10 8 7 10 7 2 7 6 7 7 3 7 Large RTO with spot markets

6 6 6 3 3 2 6 4 7 2 2 4 Smaller ISO

1 3 2 1 2 1 2 3 2 2 2 2 Interior west & upper Midwest (non-MISO)

7 6 6 2 2 2 5 4 2 5 2 4 Large vertically integrated utility

1 3 2 1 2 1 2 4 2 2 2 2 Smaller Vertically Integrated Local Utility

8 Unconstrained hydro system

3 Heavily fish constrained hydro system

1 1 1 1 1 1 1 1 1 1 1 11 Weightings Factors

Accommodating Wind and Solar Integration

Adapted from Milligan, M.; Kirby, B.; Gramlich, R.; Goggin, M. (2009). Impact of Electric Industry Structure on High Wind Penetration Potential. 31 pp.; NREL Report No. TP-550-46273. http://www.nrel.gov/docs/fy09osti/46273.pdf

Pathways to achieve "big" and "fast"

3.

Coordinated

commitment

2.

Coordinated

dispatch

1. Reserve-

sharing

Zonal to

nodal

Ancillary

service:

joint

provision

15 minutes

to 5

minutes

Revise

interchange

from 1 hour to

15 minutes

Spin, non-spin, ramp,

frequency response

Levels of Operational Coordination

Operational Evolution/Speed

Non-market Mechanisms

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Explored the economics of several nuclear-renewable hybrid energy systems:

• Determine optimal systemconfiguration includes a nuclearreactor generator, a thermal product such as steam, or heat transfer fluid

• Generate zero-carbon dispatchableelectricity and provide zero-carbon energy for industrial processes at a lower cost

SYSTEMS

SOLUTIONS

MAC

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ERGIS Visualization

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Thank you to 21CPP Participating Governments and Partners.

For questions about the 21CPP or how you can become involved, contact us at:

21stCenturyPower@nrel.gov

Collaborating CEM Initiative Websites:

❖International Smart Grid Action Network

http://www.iea-isgan.org/

❖Multilateral Solar and Wind Working Group

http://www.cleanenergyministerial.org/Our-Work/Initiatives/Solar-and-Wind

❖Global Superior Energy Performance

http://www.cleanenergyministerial.org/Our-Work/Initiatives/Buildings-and-Industry

❖Super-Efficient Equipment and Appliance Deployment

http://www.cleanenergyministerial.org/Our-Work/Initiatives/Appliances

❖Clean Energy Regulators Initiative

http://www.leonardo-energy.org/webinar/clean-energy-regulators-initiative-webinar-programme

❖Clean Energy Solutions Center : Advisory support to all governments on PST via the Solutions Center

https://cleanenergysolutions.org/

FOR MORE INFORMATION