Transcript Transform PV to Load Capacity by Coupling PV Plants to

Transform PV to Load Capacity Status
by Coupling PV Plants to CAES Plants
James Mason
Renewable Energy Research Institute
ASES Forum on Solar and the Grid
Buffalo, NY – 13 May 2009
Problem: PV Electricity Supply Is Intermittent
* PV Electricity Supply Is Intermittent
- Does Do Not Meet Load Capacity Requirements
* Load Capacity = Dispatchable Power
¤ Dispatchable = Available on Demand
- PV Cannot Replace Load Capacity Plants
* PV Is Only Supplemental Electricity
* A Large Increase in PV Capacity Without Energy
Storage Increases System Variability, the Need for
Additional Reserve Capacity, and System Costs,
which Translate Into Higher Electric Bills
Northeast ISO Electricity Demand (MWh)
Time Shift Effect Matching SW PV Electricity Output to NE Load
25,000
0.14
0.12
20,000
0.1
15,000
0.08
0.06
10,000
0.04
5,000
0.02
0
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
Hour of Day
Winter NE Load
Spring NE Load
Summer NE Load
Fall NE Load
SW Solar Electricity
SW Solar Electricity (NE Time Shift)
Capacity Replacement for Northeast 10% PV with and without CAES
25,000
Electricity (MWh)
20,000
15,000
10,000
5,000
0
1
2
3
4
5
6
7
8
9
10
11 Noon
NE Summer Load
NE Load minus Distributed PV
NE Load minus SW PV
NE Load minus PV-CAES
1
2
3
4
5
6
7
8
9
10
Distributed Rooftop (30% ELCC)
SW PV (70% ELCC)
SW PV - Distributed CAES
11
12
Insolation Variability: Diurnal and Annual
Average Southwest US Insolation
Six SW Locations: 45-Year Insolation Record (1960-2005)
8,000
7,000
Insolation (Wh/m2)
6,000
5,000
4,000
3,000
2,000
1,000
0
Winter
Spring
Average SW U.S. Insolation
Summer
Fall
Minimum Site SW U.S. Insolation
Winter
The Solution to PV’s Intermittency:
Compressed Air Energy Storage (CAES)
Alabama Electric Cooperative’s McIntosh, Alabama
110 MW CAES Power Plant in Operation Since 1991
CAES Power
Plants
CAES Power
Plants
HVDC Power
Lines
DC-AC Converter
Stations
PV Power Plants
CAES Power
Plants
Underground Natural Gas Storage Sites
CAES Power Plant
Supply of PV and CAES Electricity to Local Grid
in a Coupled PV-CAES Plant Design for Load Capacity
160
Electricity Production (MWh)
140
120
100
80
69% of PV Electricity
Goes Directly to Grid
60
40
20
CAES Electricity to Grid
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
Hour of Day
Total PV Electricity (PV-CAES)
PV Electricity to Grid
Gas Turbine Electricity to Grid
Aggregate PV & GT Electricity to Grid
24
•Next CAES Plant Will Be Similar In Design to the Schematic
•Adiabatic CAES (No NG) Will Not Be Available Until Post-2020
* PV Electricity for Air Compression
Conventional CAES = 0.8 kWh In / kWh Out
Adiabatic CAES = 1.43 kWh In / kWh Out
* CAES Plant Natural Gas Consumption
Conventional CAES = 4,800 Btu (HHV) / kWh Out
* Fuel Efficiency of a Coupled PV-CAES “Peak” Power Plant
CAES Only Fuel Efficiency = 71% (3412/4800)
Aggregate Electricity Supplied to Grid = 64% PV and 36% CAES
Aggregate PV-CAES Fuel Efficiency = 191% (3412/1786)
* Conclusion: Coupled PV-CAES Provides Load Capacity, and
Significantly Reduces Fuel Consumption and CO2 Emissions
Peak Electicity Prices
$300
255
Electricity Price ($/MWh)
$250
215
203
$200
200
177
157
$150
150
137
108
108
108
$100
76
76
76
$50
$0
PV with NG Reserve
PV-CAES
Levellzed Electicity Price PV @ $3/W
Levelized Electicity Price PV @ $1.50/W
PV-aCAES
(not exist)
NG SC
NGCC with CCS
(not exist)
Levelized Electicity Price PV @ $2/W
NG Cost for PV-CAES to Achieve Breakeven Peak Electricity Price
1. PV-CAES = Natural Gas Combined-Cycle with CCS
A. $2/W Installed PV Cost
-Natural Gas Electric Utility Price = $15.17/MMBtu
* 117% higher than current natural gas price.
B. $1.50/W Installed PV Cost
-Natural Gas Electric Utility Price = $11.63/MMBtu
* 66% higher than current natural gas price.
2. PV-Adiabatic CAES = Natural Gas Combined-Cycle with CCS
A. $2/W Installed PV Cost
-Natural Gas Electric Utility Price = $15.83/MMBtu
* 126% higher than current natural gas price.
B. $1.50/W Installed PV Cost
-Natural Gas Electric Utility Price = $12.34/MMBtu
* 76% higher than current natural gas price.
Peak Power Plant CO2 Emissions
450
CO2 Emissions (kg/MWh)
400
350
300
250
421
200
150
220
100
111
50
63
-
22
PV-aCAES
(not exist)
PV-CAES
PV with NG Reserve
CO2 Emissions (kg/MWh)
NG SC
NGCC with CCS
(not exist)
Cost of CAES Power Plant
The levelized cost estimates are calculated by the net present value cash flow method.
Financial assumptions: capital structure 80% debt – 20% equity; cost of debt 6.5%;
cost of equity 10%; ; 30-year capital recovery period; 38.2% tax rate, MACRS
depreciation; 2% annual inflation rate.
Succar and
Williams, 2008
EPRI, 2003
Mason et al, 2008
(2010)
610
440
621 (800)
1.95
1
2
Storage hrs
88
10
110
Total Capital Cost
782
450
821 (1100)
Reference
Capital Cost of CAES
surface equipment
($/KWe)
Cost of underground
storage capacity ($/kWh)
Number cycles per year
328
Levelized Cost ($/KWh)
0.039 (0.044)
Underground Natural Gas Storage Sites
Sizing PV and Air Storage Capacity
1. Size of Air Storage Reservoir Must Account for Solar
Variability to Insure Sufficient Air Supply
2. The Optimized Peak PV-CAES Plant Model Indicates
That Air Storage Capacity Must Be Sufficient to
Enable 110 hours of CAES Operation Independent
of Air Storage Recharging (40-60 million cubic feet)
3. Our Optimization Is Based on Insuring Peak Load
Capacity Electricity Supply 99.5% of the Planned
Operation of the CAES Plant
4. The Optimized Ratio of PV Capacity to CAES Peak
Load Capacity Is 1.45:1
Sizing of Air Storage Reservoir and PV Capacity Assigned to
Air Compression Has to Account for Insolation Variability
Six SW Locations: 45-Year Insolation Record (1960-2005)
8,000
7,000
Insolation (Wh/m2)
6,000
5,000
4,000
3,000
2,000
1,000
0
Winter
Spring
Average SW U.S. Insolation
Summer
Fall
Minimum Site SW U.S. Insolation
Winter
Number of Days per Year Air Storage Reservoir Is Depleted
An Important Factor in Selecting the Size of Storage Reservoir
30
Number of Days per Annum
25
20
15
10
5
0
1961
1964
1967
1970
1973
1976
1979
1982
1985
1988
1991
Peak PV-CAES Air Storage Depletion
1994
1997
2000
2003
Air Storage Balances of the CAES Underground Reservoir
To Insure CAES Plant Availability 99.5% of Planned Operation
80
Daily Air Storage Balances (million kg)
70
60
50
40
30
20
10
0
1961
1964
1967
1970
1973
1976
1979
1982
1985
1988
1991
Peak PV-CAES Air Storage Balances
1994
1997
2000
2003
Effect of Distributed PV Plants Coupled to Distributed CAES
Plants on Levelized Electricity Price Compared to SW PV
0.18
Cost of Electricity ($/kWh)
0.17
0.16
0.15
0.14
0.13
0.12
0.11
0.1
3.4
3.9
4.4
4.9
5.4
5.9
Insolation (kWh/m2/day)
LCOE for Southwest PV and Distributed Peak CAES Sites
LCOE for Distributed Peak PV-CAES Sites
6.4
Immediate Needs
1. Define CAES in Renewable Energy Incentives
- Legislatures and Regulatory Agencies
2. Federal Plan for a HVDC Grid from Southwest
to Electricity Markets in Southeast and Along
Eastern Seaboard
3. Federal Adiabatic-CAES R&D Program
Acknowledgements
• Ken Zweibel – George Washington University
• Vasilis Fthenakis – Columbia University and
Brookhaven Nat’l Lab
• Tom Hansen – Tucson Electric Power
• Thomas Nikolakakis – Engineering Grad