economics of storage local meeting - july 8, 2009
DESCRIPTION
ECONOMICS OF STORAGE LoCal Meeting - July 8, 2009. Presented by Mike He and Prabal Dutta. Lots of Storage Technologies. Pumped Water. LiSulphur. NiMH. SMES. Supercap. NiCad. Flywheel. EEStor. Li+. Thermal. Compressed Air. LiPoly. LiSulphur. Why Store Energy?. Peak-to-Average - PowerPoint PPT PresentationTRANSCRIPT
ECONOMICS OF STORAGE LoCal Meeting - July 8, 2009
Presented by Mike He and Prabal Dutta
Lots of Storage Technologies
NiMHNiCad
Li+LiPoly
LiSulphur
LiSulphurSupercap
EEStorCompressed Air
Pumped WaterSMES
FlywheelThermal
Why Store Energy? Peak-to-Average
Reduce electricity rate by shaving peak load
Match Supply and Demand When supply/demand is inelastic or
intermittent Economic Arbitrage
When price of electricity varies substantially and
An efficient market exists to buy and sell real energy
Peak-to-Average When electricity cost is set by peak
power draw Peak-shaving yields big dividends Benefits accrue at all times, not just at
peak load times Load shift if possible Generate electricity locally if feasible
economically LoCal
Buy electricity when local demand is low Convert and store electricity for later use Convert and use electricity when highest
local demand
Match Supply and Demand When supply/demand is inelastic or
intermittent Solar
S/D well-matched for typical industrial loads; storage overkill
S/D poor-match for early morning or evening residential loads
Wind S/D matching is variable, TBD
Statistical multiplexing plays a role in smoothing out
LoCal Store when supply is high but demand is low Use when supply is low but demand is high
Economic Arbitrage When a sufficient wholesale price
difference exists Buy electricity when price is low Convert and store electricity for later sale Convert and sell electricity when price is
high
IESO: A Concrete Analysis
http://www.iemo.com/imoweb/marketdata/marketToday.asp ($1 CAD = $.86 USD)
Ontario IESO (July 7, 2009) Wholesale electricity price ($CAD/MWh)
Min: $3.52 Avg: $20.99 Max: $42.32 Range: $38.80
Average hourly demand Min: 15,000 MW Avg: 17,162 MW Max: 19,570 MW Range: 5,070 MW
Ontario IESO (July 7, 2009)
Price and Demand vs ToD
0.00
5.00
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45.00
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Hour of Day
Pric
e ($
/MW
h) a
nd D
eman
d (G
Wh)
Price ($/MWh)Demand (GWh)
Ontario IESO (July 7, 2009)
Price vs Demand
0
5
10
15
20
25
30
35
40
45
14000 15000 16000 17000 18000 19000 20000
Demand (MWh)
Pric
e ($
/MW
h) ?
Ontario IESO (July 7, 2009)
Wholesale Price and Uplift Charge
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5.00
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45.00
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Hour of Day
Char
ge ($
CAD/
MW
h)
PriceUplift
Storage Economics To be marginally viable, must satisfy:
CostPUE / PriceDeltaPUE < CycleLife CostPUE / PriceDeltaPUE => cycles needed
to profit Where
CostPUE is Cost per unit of energy storage Li+ (e.g. $300/kWh) Pumped Hydro ($10-$45/kWh)
PriceDeltaPUE is max(price) - min(price) per unit energy
CycleLife is number of cycles of storage technology
Storage Economics IESO Case Study on July 7, 2009
PriceDeltaPUE = $38.80 (CostPUE / PriceDeltaPUE / CycleLife) ?<?
1 Tech CostPUE PDPUE CycleLife LHS Li+ $300/kWh $.0388/kWh 1200
6.44 Pump. Hydro $45/kWh $.0388/kWh Inf (need 1160)
<1
Energy Density
Cost
Lifetime vs Efficiency
Per-cycle Cost
Summary TableStorage Technology
Energy Density Cost Self-discharge Round Trip Efficiency Lifetime
Thermal (various media)
20-80 kWh/m3 $40-65/ kWh 1-2% per day 90% Unlimited
Flywheel 0.2 Wh/kg $300/kWh Minimal 80-90% ~20 years
Compressed Air 2 kWh/m3 $1-5/kWh (storage only)
None 80% Unlimited
Superconducting Magnetic Energy Storage
1-10 Wh/m3 $54,000/kWh None with cooling 90-95% Unlimited
Pumped Hydro 0.3 kWh/m3 @ 100m $10-45/kWh None 75% Unlimited
NiMH Battery 30–80 Wh/kg $364/kWh 30%/month 66% 500-1000 cycles
NiCad Battery 40-60 Wh/kg $400/kWh 20%/month 70-90% 1500 cycles
Lithium Ion Battery
160 Wh/kg $300/kWh 5%/month 99.90% 1200 cycles
Lithum Polymer Battery
130-200 Wh/kg $500/kWh 10%/month 99.50% 1000 cycles
Lead Acid Battery
30-40 Wh/kg $100-200/kWh 3%-4%/month 70%-92% 500-800 cycles
Sample Load Profiles
0 5 10 15 20 250.4
0.6
0.8
1
1.2
1.4
1.6
1.8
Time (hr)
Load
(kW
)
Warm Summer Weekday
0 5 10 15 20 250.4
0.5
0.6
0.7
0.8
0.9
1
1.1
1.2
1.3
Time (hr)
Load
(kW
)
Warm Summer Weekend
Sample Load Profiles
0 5 10 15 20 250.5
0.6
0.7
0.8
0.9
1
1.1
1.2
1.3
1.4
Time (hr)
Load
(kW
)
Mild Spring Weekday
0 5 10 15 20 250.4
0.5
0.6
0.7
0.8
0.9
1
1.1
1.2
1.3
Time (hr)
Load
(kW
)
Warm Autumn Weekend
Marginal revenue potential drops quickly and varies
Mild Spring Weekend Day Warm Summer Weekday
Storage power density matters:Small window to buy cheap
Mild Spring Weekend Day Warm Summer Weekday
1x
Power Density
2x
Buy-low/sell-high cycle rateis limited: must hold for a while
Price and Demand vs ToD
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Hour of Day
Pric
e ($
/MW
h) a
nd D
eman
d (G
Wh)
Price ($/MWh)Demand (GWh)
Unexpected arbitrage cancreate opportunistic profits
http://www.iemo.com/imoweb/marketdata/marketToday.asp ($1 CAD = $.86 USD)
Must disentangle residential, commercial, industrial, and night life/party loads
Price and Demand vs ToD
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5.00
10.00
15.00
20.00
25.00
30.00
35.00
40.00
45.00
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
Hour of Day
Pric
e ($
/MW
h) a
nd D
eman
d (G
Wh)
Price ($/MWh)Demand (GWh)
OntarioNight Life
Limitations Assumes Time-of-Use pricing Assumes zero price-elasticity
For marginal profit potential analysis Likely reality: price sensitivity high at peak
load times Garbage-in/Garbage-out
Wholesale prices and load profiles are average values
No distinction between $USD and $CAD Only a marginal viability analysis
Average-case viability much lower
Takeaways Storage still has a long way to go for
economic viability in financial arbitrage Peak to average case may be more
economically viable Cost, power density, efficiency, cycle life
are important factors Need a metric for: Capacity X CycleLife 100W lightbulb for a day = Raising a car
~1km