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Large-Scale Energy-Storage Systems – Technologies

and Applications.E. Peled,

Tel Aviv UniversityFrance - Israel Energy Meeting,Tel Aviv, 10-11, November, 2010

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Benefits of Energy Storage• •Generation• –Spinning Reserve• –Capacity Deferral• –Frequency Regulation• –Load Leveling• –Renewable Support

• •Transmission & Distribution• –Line and Transformer Deferral (Solar / wind farms will be located far

from the customers)• –Grid stability

• •End-Use• –Power Quality/Reliability• –Peak Load Reduction• –Distributed Generation Support

100GW of pumped-hydro storage already installed world-wide

310/29/2009 3

.... Flexible Deployment

Electrical Energy Storage can be Connected in Several Strategic Locations:

At the Load

At Transmission Nodes

At Conventional Power Plants

At Renewable Energy Sites

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• Shifting capacity night to day.• Lowering need for spinning reserve.• Lowering the need for new installations.

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Energy Storage in Solar

Solar Power storage reduces conventional

generation requirements(3000MW 2000MW)

Without Storage

With Storage

30002000

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Fast power fluctuations for a 4.6 MW solar PV array in Arizona (10 sec resolution)

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7 days power fluctuations for a 4.6 MW solar PV array in Arizona (1min resolution)

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Wind Farm Applications:Peaking Power Component:- Firming (6 to 12 hours of storage)Frequency Regulation Component:- Stabilization (smoothing)

v

Peak Power Services

Frequency Regulation Services –stabilization of Power through fast

response smoothing

v

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Energy Storage – Wind Applications• Overcome intermittent nature of wind power • “Capacity Firming”

– Avoid penalties (power below forecast)– Utilize power above forecast– Price arbitrage / profit maximization

• Power supply at slow wind• Enable increase in wind penetration (>20%)• Stabilization of power through fast response

smoothing

32MW farm using 4MW 1.5hour VRB ESS – Sapporo-Japan

Better power smoothing requires larger ESS system

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Wind energy cost approaching conventional energy cost

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Annual Wind Installation

$19.5B

Wind accounted for 40% of allglobal renewable energy investments in 2005

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Geographic Penetration

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Competitive analysis

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10,000

1,000

100

100 1,000 10,0003,000300

$ / kW

$ / k

Wh

Source: Energy Storage Association

VRB

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EnStorage ESS system based on HTB RFC(based on technology developed at my group)

Hydrogen

Regenerative Fuel Cell

Bromine

Electric Power

Hydrogen

Regenerative Fuel Cell

aqueous hydrogen tribromide solution

Electric Power

Hydrogen

Regenerative Fuel Cell

Aqueous Hydrogen Bromide solution

Electric Power

Hydrogen

Regenerative Fuel Cell(FC & Electrolyzer)

Electric Power

• Totally sealed system• No emissions or solid waste• Infinite electrolyte life• >75% total efficiency

Power Generation250kW to 1GW

Proprietary Membrane:3x higher power density

3x lower cost/kW

Energy Storage1MWh to 10GWh

lower cost chemicals4x lower cost/kWh

3HBr H2+HBr3

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• Pumped - Hydro storage technology– Larger than 100MW units– The lowest cost ESS – Usually in conjunction with hydroelectric generation – Generally not economical otherwise– Israel Electric Company evaluating 800MW installations (~8% of

peak demand)

EnStorage ESS based on Hydrogen Three Bromide RFC - advantages over pumped-hydro storage:

– Similar or lower cost– Faster response time (1mS vs. 10 seconds for pump hydro)– Short term peak: up to 2-3x average output– Lower footprint– No dependence on topography

• can be located in proximity to customers• Applicable to distributed storage

Comparison between Enstorage ESS and pump hydro ESS

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EnStorage energy storage system (ESS)

20 kW stack

20kW stack

DryerCompressor

Expander

Hydrogen tanksHBr + Hydrogen-Tribromide solution tanks

Pump

50-100 Stacks in ParallelSingle or multiple storage tanks

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RFCHBrTo

HBr3

HBr/HBr3 solution tanks

H2Cylinder

Power in

Charge mode:1. Power is supplied to Regenerative Fuel

Cell.

2. HBr is converted to HBr3.

3. Hydrogen is generated.

Discharge mode:1. Power is generated by the

Regenerative Fuel Cell

2. Hydrogen is consumed.

3. HBr3 is converted back to HBr.RFCHBr3

to HBr

HBr/HBr3 solution tanks

H2Cylinder

Power out

EnStorage energy storage concept

3HBr H2+HBr3

3HBr H2+HBr3

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HBr3-

solution

HBr3-

solution

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PEM FC stack

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Enstorage Membrane Production: Continuous Coater

•• 33cm wide sheet 33cm wide sheet •• 15m15m22/h (30kW/h)/h (30kW/h)

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World record in power density

1.5W/cm2

Peak power

0.2W/cm2 operating point

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Flow Batteries

24EnStorage Confidential

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Main concept:

1. Based on Vanadium Red-Ox chemistry.

2. Vanadium solutions are circulated both on anode and cathode.

3. Storage capacity (Energy) is based on tanks volume. Power is based on the size of the active electrodes .

4. Membrane is used for separation between anode and cathode.

5. Cation exchange membrane is used.

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Tanks

Stacks

•Expensive salts•Membrane price•High cycle #

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•Expensive organic complex•limited cycle #• requires 100% DOD ever few cycles.•Capacity & power conjoined

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EnStorage (HTB RFC)

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Summary• There is a large need for electric energy storage systems

for grid applications and for wind and solar (PV) farms.• In many cases the solar and wind generation sites are far

from the customers, thus storage is critical.• Each 5MW wind turbine needs a 1MW - 6 hours ESS.• At present the only technology that meets the cost goal is

pump hydro (100 GW installed).• All batteries are too expensive, have too short cycle or

calendar life, thus applicable for a short time storage only.

• The Enstorage Regenerative Fuel Cell ESS is expected to meet the performance requirements and the cost goal, especially for large systems and many hours of storage.

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Thank you for your attention