J. Hemrle, M. Mercangoez, L. Kaufmann, Ch. Ohler, ABB Corporate Research; SCO2 Symposium, May 24th, 2011
Thermo-Electric Energy Storage TEES concept – Invitation © ABB Group May 23, 2011 | Slide 1
Energy storage system (ESS) applications ESS
Central Generation
Load leveling
Spinning reserve
for generation utilization 100 MW, 4h
In case of line loss 10-100 MW, 0.25-1 h
ESS
220 kV Overhead line 20 kV
220 kV
Load leveling for postponement of grid upgrade ESS 1-10 MW, 6 h
Distributed Generation
ESS
Integration of renewables
110 kV
20 kV Network ring
1-100 MW, 1-10 h
Frequency Regulation © ABB Group May 23, 2011 | Slide 2
ESS 0.5-10 MW, 1 h
ESS 110 kV
Heavy Industry
Peak shaving
Single connection
20 kV
to Load
1-50 MW, 0.25-1 h
Electric energy storage applications
Storage time [min]
1000
Renewable integration 10 h Deferral of T&D upgrade
300
Generation load leveling 100 1h 30
10
Uninterruptible power supply
100 kW
1 MW
Frequency regulation 10 min 10 MW
100 MW
Power requirement [MW] © ABB Group May 23, 2011 | Slide 3
1000 MW
German & Swiss Electricity Price Dec 7-27, 2009
© ABB Group May 23, 2011 | Slide 4
Bulk electricity storage technologies PHS Efficiency
70% to 84%
Duration of power supply
Hours to days
Power
10 MW to 1 GW
Total capital cost (100 MW plant)
2‘700 to 3‘300 $/kW (Upgrade 600 $/kW)
Biggest disadvantage
Geographically limited
CAES Efficiency
42% CAES, 70% target for A-CAES
Duration of power supply
Hours to days
Power
100 MW to 1 GW
Total capital cost
800 $/kW for storage equipment (without power plant)
Biggest disadvantage
Geographically limited, low efficiency; ACAES not mature, technically challenging NaS battery storage
© ABB Group May 23, 2011 | Slide 5
Efficiency
75%
Duration of power supply
Seven hours
Power
1 to 50 MW
Total capital cost
2500 $/kW
Biggest disadvantage
Linear scaling (no economy of size)
Electricity storage – thermal approach Two options
Limited by Carnot efficiency → high temperature storage.
η RT
© ABB Group May 23, 2011 | Slide 6
Heat pump
Heat engine
(charging)
(discharging)
ηTE ⋅ Q& TE , HS ⋅τ D W&TE ⋅τ D τ = = → ηTE ⋅ copHP = D W& HP ⋅τ C (1 / copHP ) ⋅ Q& HP , HS ⋅τ C τC
Any cycle that can be economically run and reversed with high reversibility.
Thermoelectric Energy Storage (TEES) „Power plant-like“ site independent bulk storage
Water as storage material
Turbomachines for compressors and turbines
© ABB Group May 23, 2011 | Slide 7
Storage of electricity in the form of heat with heat pump charging and heat engine discharging
Transcritical CO2 as the working fluid of the cycle
TEES Charging
© ABB Group May 23, 2011 | Slide 8
TEES Discharging
© ABB Group May 23, 2011 | Slide 9
TEES Main features
Low-temperature storage with heat pump charging and heat engine discharging Water as storage material Transcritical thermodynamic cycle: CO2 as working fluid Options for improvements (efficiency or cost) and modularity at favorable locations:
Synergy with low- and very-low-grade (waste) heat sources
Availability of a large cold heat bath
Environmentally benign
Economy of size
© ABB Group May 23, 2011 | Slide 10
Large capacity, site-independent electric energy storage system
Synergy with other emerging supercritical CO2 technologies in heat pumps, waste heat recovery and geothermal power
TEES Efficiency
Target: 60% to 75%
Duration of power supply
Hours to days
Power
Tens to hundreds of MW
Total capital cost
1000 to 1800 $/kW
Biggest disadvantage
Not a mature technology
TEES Real cycle and Heat integration
© ABB Group May 23, 2011 | Slide 11
TEES plant Layout and main components
© ABB Group May 23, 2011 | Slide 12
TEES performance estimation Development scenarios Scenario Off-the-shelf (conservative)
-Based on off-the-shelf components -Conservative estimate of efficiencies -Low tens of MW size -Turbine efficiency 88%
Expected
-2 to 5 years of development -50 MW -Customized machines -Improved transient plant behavior -Learning included -Turbine efficiency 91%
Developed (optimistic)
-5 to 10 years of development -100 MW -Custom machines (efficiencies of CO2 machines at same level as existing steam cycle components) -Cost and efficiency benefits due to scaling -Turbine efficiency 94%
Heat exchangers
© ABB Group May 23, 2011 | Slide 13
Low cost (performance) of heat exchangers
-Pinch in gas heater/cooler, 2.5 K -Pinch in evaporator/condenser, 3K
High cost (performance) of heat exchangers
-Pinch in gas heater/cooler, 1 K -Pinch in evaporator/condenser varies from 3/3 to 2/0.5
TEES performance Efficiency
Exergy losses: Charging
70
Discharging Round-trip efficiency [%]
65 60 55 50 45
Compressor Expander
40
Pump
35
Turbine
30 55
65
75
85
Turbomachine e fficiency [%]
© ABB Group May 23, 2011 | Slide 14
95
105
TEES performance Cost Three
cost estimate scenarios
Size [MW]
Heat exchanger cost
Total plant investment cost (optimistic to pessimistic) [EUR/kW]
50
high
1000 – 1900
low
800 – 1400
high
750 – 1500
low
600 – 1000
150
Marginal
storage capacity costs ~15 – 30 EUR/kWh
(included in total costs)
© ABB Group May 23, 2011 | Slide 15
TEES thermo-economic optimization EPFL (Lausanne): M. Morandin, S. Henchoz
© ABB Group May 23, 2011 | Slide 16
TEES Thermo-economic optimization
Off the shelf: T 0.88, C 0.86, E 0.85, P 0.85; Expected: T 0.91, C 0.89, E 0.88, P 0.86;
© ABB Group May 23, 2011 | Slide 17
TEES Profitability and comparison
NaS
© ABB Group May 23, 2011 | Slide 18
TEES with waste heat utilization Cheap heat + cheap electricity = Expensive electricity
© ABB Group May 23, 2011 | Slide 19
TEES Cold side
Tcold=6°C
1.35 Tcold=12°C
RT-Efficiency
1.15
0.95 Tcold=18°C
0.75
0.55
0.35 -5
© ABB Group May 23, 2011 | Slide 20
5
15
25 35 45 55 65 75 Tcold / Twaste heat (°C)
85
95
TEES: Done, status, next
Components
Towards optimized machines
Ice storage
Heat exchangers
High pressure
Narrow approach temperatures
Heat exchanger network design
Electrical components
© ABB Group May 23, 2011 | Slide 21
Technical feasibility cleared but scaling and costs to be improved
Relatively new area: Space for improvement?
Further optimization
Conceptual studies to continue
© ABB Group May 23, 2011 | Slide 22
