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Ramping and Demand Shifting: A Case Study Tim Mount Dyson School of Applied Economics and Management Cornell University [email protected] Demand Response Workshop Cornell, January 17, 2011
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Ramping and Demand Shifting:A Case Study
Tim Mount
Dyson School of
Applied Economics and Management
Cornell University
Demand Response WorkshopCornell, January 17, 2011
Results from Previous Research
Page 2
Rate Payments by a Wholesale Customer =Billing Cost + Wholesale Price x MWh + Capacity Price x MW
Adding wind generation will result in: Wholesale Energy Prices going DOWN Capacity Prices going UP (MORE MISSING MONEY/MW)
The financial viability of controllable demand and storage depends on getting paid correctly for providing servicesBuying low at night and selling high during the day (peak shifting)Paying lower capacity charges by reducing demand at the system peakReceiving payments for providing ramping services as well as regulation
Page 3
PART 1
Specifications for the Case Study
Criteria used for the Optimum Dispatch2
OBJECTIVE FUNCTION FOR PLANNINGMinimize the expected annual cost of operations over a set of credible contingencies, Including the costs of load-not-served, reserves and ramping (+incremental capital). subject to
network constraintsoperating reliabilitysystem adequacy(financial adequacy)
Page 5
30-BUS TEST NETWORK
Area 1- Urban- High Load- High Cost- VOLL = $10,000/MWh
Area 3- Rural- Low Load- Low Cost- VOLL = $5,000/MWh
Area 2- Rural- Low Load- Low Cost- VOLL = $5,000/MWh
Wind Farm
Specifications for a Windy Day
System Conditions- Typical Demand Cycle- Wind is 25% of Demand- Three Big Cutouts
Research Questions- How much potential wind is dispatched?- How much capacity is needed for reliability?
Underlying Policy Question for Renewables- More transmission capacity v More efficiency using DER
Page 7
PART 2
Results of the Case Study
Effects of Including Ramping CostsPage 8
Case 2n: No Ramping Costs Case 2: With Ramping Costs
Wind variability mitigated by GCTLESS wind dispatched
Wind variability mitigated by CoalMORE wind dispatched
RAMPING COSTS MATTER
Effects of Including Ramping Costs(Typical Day with 0MW/50MW of Wind Capacity)
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NOWind Capacity
Case 1n: NO Ramping Costs
Case 1: WITHRamping Costs
Percentage Change
Operating Costs:$1000/day 109 118 +8.26
Conventional Capacity Committed: MW 224 224 0.00
50MWWind Capacity
Case 2n: NO Ramping Costs
Case 2: WITHRamping Costs
Percentage Change
Operating Costs:$1000/day 80 92 +15.00
Conventional Capacity Committed: MW 273 255 -6.59
Potential Daily Wind Dispatched: % 88 43 -51.14
Effects of Constant Wind(Typical Day with Ramping Costs)
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50MWWind Capacity
Case 2: Normal Wind
Case 4Constant Wind
Percentage Change
Operating Costs:$1000/day 92 83 -9.78
Conventional Capacity Committed: MW
255 225 -11.76
Potential Daily Wind Dispatched: % 43 74 +72.09
Lower Operating Costs/ More Wind DispatchedLess Capacity Needed/ Cutouts Eliminated
Effects of Two Wind Sites(Typical Day with Ramping Costs)
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50MWWind Capacity
Case 2: Normal Wind
Case 7Two Wind Sites
Percentage Change
Operating Costs:$1000/day 92 81 -11.96
Conventional Capacity Committed: MW 255 265 +3.92
Potential Daily Wind Dispatched: % 43 60 +39.53
Lower Operating Costs/ More Wind Dispatched- Not as low as constant wind
Slightly More Capacity Needed
Effects of No Network Congestion(Typical Day with Ramping Costs)
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50MWWind Capacity
Case 7:Two Wind Sites
Case 3No Congestion
Percentage Change
Operating Costs:$1000/day 81 58 -28.40
Conventional Capacity Committed: MW 265 271 +2.26
Potential Daily Wind Dispatched: % 60 62 +3.33
Lower Operating Costs/ Similar Wind Dispatched- Merit order dispatch BUT the cutouts are still there
Similar Capacity Needed- The cutouts are still there
Effects of Demand Ramping(Typical Day with Ramping Costs)
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50MWWind Capacity
Case 7:Two Wind Sites
Case 8:Two Sites + DR
Percentage Change
Operating Costs:$1000/day 81 77 -4.94
Conventional Capacity Committed: MW 265 242 -8.70
Potential Daily Wind Dispatched: % 60 65 +8.33
Lower Operating Costs/ More Wind Dispatched- The gains are modest
Less Capacity Needed- The cutouts are mitigated
Effects of Flat Demand + DR I(Typical Day with Ramping Costs)
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50MWWind Capacity
Case 7:Two Wind Sites
Case 9:Two + Flat + DR
Percentage Change
Operating Costs:$1000/day 81 55 -32.10
Conventional Capacity Committed: MW 265 206 -22.26
Potential Daily Wind Dispatched: % 60 77 +28.33
Lower Operating Costs/ More Wind Dispatched- The gains are substantial
Much Less Capacity Needed- The cutouts are mitigated AND the peak load is reduced
Effects of Flat Demand + DR II(Typical Day with Ramping Costs)
Page 15
Case 7: Two Wind Sites Case 9: Two + Flat + DR
Lower Operating Costs/ More Wind Dispatched- The gains are substantial
Much Less Capacity Needed- The cutouts are mitigated AND the peak load is reduced
No Congestion v Flat Demand + DR(Typical Day with Ramping Costs)
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50MWWind Capacity
Case 3:No Congestion
Case 9:Two + Flat + DR
Percentage Change
Operating Costs:$1000/day 58 55 -5.17
Conventional Capacity Committed: MW 271 206 -23.99
Potential Daily Wind Dispatched: % 62 77 +24.19
Similar Operating Costs/ More Wind Dispatched- Merit order dispatch v mitigated variability
Much Less Capacity Needed- The cutouts are mitigated AND the peak load is reduced
Conclusions
• Ramping costs combined with the high probability of cutouts results in less wind dispatched,
• Eliminating network congestion does not eliminate the adverse effects of wind variability (more wind dispatched but the same capacity needed for reliability),
• The main benefit of using controllable demand to mitigate wind variability is to reduce the capacity needed,
• Using controllable demand (electric vehicles and thermal storage) to flatten the daily pattern of demand and mitigate wind variability is the big winner. More wind is dispatched and much less capacity is needed.
Page 17
