Making Clean Local Energy Accessible Now September 12, 2013 Enhances System Reliability & Efficiency Distributed Generation + Intelligent Grid (DG+IG)

Making Clean Local Energy Accessible Now September 12, 2013

Enhances System Reliability & Efficiency

Distributed Generation + Intelligent Grid (DG+IG)

Stephanie WangRegulatory Policy DirectorClean [email protected]

Making Clean Local Energy Accessible Now

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Contents of DG+IG Presentation

• Overview of Grid Support Services

• DG+IG Balances Voltage

• DG+IG Balances Power & Frequency

• DG+IG Can Replace SONGS


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Overview of Grid Support Services

Service Summary

Voltage Control• Keep voltage within optimal range by injecting and absorbing

reactive power.

Power Balancing

• Includes Regulation, Load Following/ Energy Imbalance, Operating Reserves.

• Balance real power supply and demand, keep frequency within optimal range.

Frequency Response

• Provide real power to respond to sudden losses of large generators or transmission lines.

Forecasting • Forecast power supply and demand.

Grid support services enable the reliable operation of electric grid systems.


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Overview of Grid Support Services

A number of studies, however, suggest that, as intermittent renewables become a larger presence in U.S. electricity generation, that 1% requirement will grow.

Balancing powersupply

and demand

Control voltage with reactive power

Source: Oak Ridge National Laboratory (2004)


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DG+IG Enhances System Efficiency & Reliability






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Distributed Advanced Inverters Balance Voltage

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 290.9

0.95

1

1.05

1.1

IG Corrects Overvoltage

IG Corrects Undervoltage

Source: Clean Coalition, 2013

Upper Limit

Lower Limit

Nominal Voltage

sec

per unit voltage

Advanced inverters locally absorb reactive power

Advanced inverters locally supply reactive power

“Reactive power supply is the key controller of voltage in alternating current (AC) power systems. Reactive power supplied locally could be a major player in improving system reliability as well as improving system efficiency.”

Oak Ridge National Laboratory (2008)


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DG+IG Core Solutions for Voltage Regulation

Solutions Benefits

Distributed Generation

• Provisions reactive power where it’s needed most for regulation• Avoids line losses• Reduces congestion of transmission and distribution lines

Advanced Inverters(paired with solar,

storage)

• Provisions distributed reactive power • Reacts automatically within fractions of a second (conventional

resources can take minutes to react)• Converts real power from the grid to reactive power 24/7/365• Oversized inverters can deliver reactive power without reducing DG

real power output• Ride-through voltage events, remain attached longer than

conventional spinning generators without harm• Modern inverters already have these advanced capabilities

Energy Storage(batteries, flywheel)

• Provisions both real and reactive power• Generally paired with advanced inverters


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Distributed Voltage Regulation – Location Matters

Efficient & reliable reactive power

(Advanced Inverters)

Benefits of distributed voltage regulation:• Enhances system reliability by providing

reactive power where needed• Improves system efficiency by avoiding

line losses and reducing congestion



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Distributed Voltage Regulation – Location Matters

“The old adage is that reactive power does not travel well.”


Source: Oak Ridge National Laboratory (2008)

T&D lines absorb 8-20x more reactive power than real power.

Prevent Blackouts:When a transmission path is lost, remaining lines are heavily loaded and losses are higher.


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Advanced Inverters Keep Voltage in Balance

• An inverter converts direct current (DC) to alternating current (AC) power.

• Advanced inverters from Germany to State of Georgia have been programmed to deliver reactive power.

• Proposed changes to IEEE 1547a and UL standards will allow advanced inverters to provide reactive power for voltage regulation in California.

Source: EPRI (2011)


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Advanced Inverters – Voltage Ride Through

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

110%

120%

130%

140%

Volt

age

Time (1 sec/div.)

EXISTING AND RECOMMENDED VOLTAGE RIDE THROUGH

EXISTING IEEE-1547

LIMIT d

LIMIT c

EXISTING IEEE-1547

LIMIT a

LIMIT b

Source: CPUC Advanced Inverters Working Group, SCE Comments, 2013

Enhanced Ride Through

U.S. standards require inverters to automatically disconnect from the grid during any voltage event. Proposed changes to IEEE 1547a in California would allow ride through, enhancing system resilience.


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Advanced Inverters – Reactive Power

P90%

Q 43.6%

S100%

REACTIVE (Q)

REAL (P)

P: Real power (kW)Q: Reactive power (kVAr)S: Total power (kVA)

100 kW solar PV AC power100 kVA inverter capacity0.9 power factor43.6 kVAr reactive power90 kW real power

Standard-sized inverter:Diverts up to 10% solar capacity

to provision reactive power

Advanced Inverter at 0.9 Power Factor = 43.6% reactive power


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Advanced Inverters – Reactive Power (Oversized)

P100%

Q 45.8%

S110%

REACTIVE (Q)

REAL (P)

100 kW solar PV AC power110 kVA inverter capacity0.9 power factor45.8 kVAr reactive power100 kW real power

Oversized inverter:• No reduction of PV real power• Draws up to 10 kW real power

from the grid• Provides reactive power

24/7/365

P: Real power (kW)Q: Reactive power (kVAr)S: Total power (kVA)


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Advanced Inverters – Costs for Producers

UC Berkeley (2013)

Oversize Inverter

Cost = (Oversized Inverter) - (Standard Inverter)

Lose Peak Real Power

An example:• 10 kW PV system• Located in SF ($0.149/kWhr)• Peak over 2 hours, PF = 0.9• Lose $109/kVAr-yr

An example:• 10 kW PV system• 11 kW Inverter• Cost = $113.5/kW

• Produce PF = 0.9• Produce 1.2 kVAr• Cost $1.2/kVAr-yr


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Energy Storage Keeps Voltage in Balance

Photos: CESA (2013)

Storage can perform all voltage regulation functions:• In addition to provisioning real power, generally paired with advanced

inverters that can provision reactive power• Batteries and flywheels can react automatically within fractions of a

second


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Conservation Voltage Reduction

120 Volts vs. 117 Volts = 2.5% drop in power usage

Potential to reduce total system power usage by up to 3%

Pacific Northwest National Laboratory (2010)


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DG+IG Balances Power & Frequency

Source: NERC (2011)


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Frequency Regulation Capacity Requirements

Navigant / Pike Research projects that U.S. frequency regulation capacity requirements will increase. In 2011, assets that provide frequency regulation amounted to about 1% of peak load.


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DG+IG Solutions for Balancing Power & Frequency

Solutions Benefits

Demand Response

• Automated demand response can address power imbalances within fractions of a second

• Reduces or shift load away from peak hours to free up other resources to provide real power

Energy Storage(batteries, flywheel)

• Supplies and absorbs power• Can reduce or shift load• Can react automatically within fractions of a second

Forecasting• Forecasting improvements will reduce unpredicted differences

between scheduled supply and actual supply

Proactive Ramp Control

• Reduce output from intermittent generators for proactive ramp control to smooth out short term variations

Curtailment• Curtail intermittent generators to flatten system-wide steep

ramps


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DG+IG Keeps Power in Balance

DR, ES

shifts load

ES, Auto-DR, Curtailment for

ramping

DR, ES

shifts load


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Power Balancing – Location Matters

Efficientpower

balancing

Benefits of distributed power balancing:• Avoids line losses • Reduces congestion of T&D lines


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DG+IG: Fast & Accurate Frequency Regulation

FERC Order 784 (July 2013) requires transmission providers to consider “speed and accuracy” when determining reserve requirements for frequency response and regulation.

Conventional Spinning GeneratorFlywheel Storage

Storage provides both supply and

demand

Faster and more accurate regulation = less MW required

Source: Beacon Power (2011)


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Proactive Curtailment for Ramp Control

• For an individual variable generation system, reduce output to control ramp down when there’s a forecasted reduction in solar/wind resources, and limit output to control ramp up.

• Puerto Rico requirement – no more than 10% of nameplate can change within 1 minute.

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 390

20

40

60

80

100

120

Solar_Clouds

Solar_Ramped

Forecast system detects cloud edge moving toward PV installation and prepares curtailment order

Start curtailment ramp down

Start curtailment ramp up

Minutes Source: Clean Coalition (2013)


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Proactive Curtailment for Ramp Control (Cont’d)

• Cost Considerations• Proactive curtailment is less expensive for solar project owners than investing

in storage in some situations.• Proactive ramp down requires MC2 equipment – must be able to monitor and

forecast resource reduction, communicate between equipment at the site, and control ramp up and down.

• Some utilities may claim that weather monitoring equipment will be expensive

• SMUD concluded that monitoring can be done with inexpensive solar battery systems generally used for grid communications.


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Frequency Response is a Regional Issue

Western Electricity Coordinating Council

(WECC)

California Independent System Operator

(CAISO)

Each ISO must provide a certain amount of real power to respond to the sudden loss of a large generator or transmission line within the region.


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Frequency Response – CAISO Obligations

Source: California ISO Frequency Response Study by General Electric (November 2011)

CAISO contribution ~650 MW

Less than 10 seconds to

respond


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Solutions for Frequency Response

Solutions Benefits

Conventional Response

(spinning reserves)

• Traditionally, in California, natural gas power plants are kept in spinning mode to meet this need.

• These spinning reserves run less efficiently b/c not running at maximum rated output.

Energy Storage(batteries, flywheel,

pumped hydro)

• Energy storage may be used to dispatch power for frequency regulation within less than a second or up to 5 seconds, depending on the technology.

• California Public Utilities Commission has set energy storage procurement targets of 1.325 GW by 2020.

Automated Demand Response

• Automated demand response can reliably free up power supply to respond within fractions of a second.

• Most existing demand response in California is too slow and not dependable enough to participate in frequency response.


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Joint Taskforce Plan for Replacing SONGS / OTC

Joint Taskforce (CPUC, CEC, CAISO) Preliminary Reliability Plan (Sept 2013)

• Issues: • Replace SONGS and ~5000 MW of retiring Once-Through-Cooling Plants• Address load growth in target areas through 2022

• Solutions: • Meet 50% of needs with 3,250 MW of local preferred resources (energy

efficiency, demand response, renewables, combined heat and power, storage)• Meet 50% of needs with transmission upgrades (including voltage support)

and 3,000 MW of conventional generation

Source: CPUC July 15, 2013


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Replace SONGS with IG Solutions

Clean Coalition Solutions:

• Recognize the full potential of local preferred resources.• Plan assumes low capacity factor for demand response. CPUC should set

realistic but ambitious demand response targets. • Plan does not include use of advanced inverters to provision reactive power.

CPUC should develop pilot project for Southern California.

• Maximize use of local preferred resources.• 50% limitation on local preferred resources is arbitrary, based on outdated

assumptions about the potential of local preferred resources, and not in compliance with the Loading Order.

• Southern California Edison’s Living Pilot should be a showcase for using local preferred resources to meet grid reliability needs.

Policy Forums:

• CPUC Long Term Procurement Plan Track 4 (SONGS)• CPUC SCE Living Pilot• CEC Integrated Energy Policy Report• CPUC Demand Response


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Replace SONGS – Demand Response

California must implement FERC Order 745 and greatly expand use of demand response. PJM was the first grid operator to comply with Order 745, and now demand response bids into PJM markets and responds like a generator.


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Replace SONGS – Solar Potential

SMUD installed 100 MW of local solar in just 2 years. Equivalent to 2.5 GW of local solar if a similar program were extended across the entire state.

Eric Garcetti committed to 1,200 MW of local solar within

LA city limits by 2016


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Replace SONGS – Solar PV + Advanced Inverters

Huntington Beach 290 MVars

(minus line losses = 261 MVars)

vs.

570 MW of local solar with advanced inverters, oversized by 10% set at 0.9 Power Factor = 261 MVArs


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Replace SONGS – Energy Storage Potential

Targets set by CPUC include 745 MW storage in Southern California

Documents

Making Clean Local Energy Accessible Now September 12, 2013 Enhances System Reliability & Efficiency Distributed Generation + Intelligent Grid (DG+IG)