compressed air energy storage...

Compressed Air Energy

Storage (CAES)

7th Energy Storage World Forum, London April 2014

ENERGY STORAGE HEAD TO HEAD

Comparing Electrochemical v Other Energy Storage Technologies – Which One Offers Optimum Return On Investment And When?

David J. Timoney

University College Dublin, Ireland

david.timoney@ucd.ie

3rd April 20141

• Large cavern is buried underground (salt mine).

• Air is compressed using “surplus” electricity during periods of low demand.

• Compressed Air must be cooled for storage.

• During times of peak demand, (heated) air is released through turbines to generate power.

Compressed Air Energy Storage (CAES)

Salt seam

cavern

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Status and Technical Challenges of Advanced Compressed Air Energy Storage (CAES) Technology, Matthias Finkenrath (GE Global Research

Europe), Simone Pazzi, Michele D’Ercole (GE Oil & Gas), Roland Marquardt, Peter Moser (RWE Power AG), Michael Klafki (ESK GmbH), Stefan

Zunft (DLR), 2009 International Workshop on Environment and Alternative Energy, Organized by C3P and NASA, Nov 10 - 13, 2009, GE Global

Research, Garching n. Munich, Germany

CAES Design Options

Fuel needed

No fuel needed

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• Provides Bulk Storage similar to Pumped Hydro.

• Capital Costs are $810-$1045 per kW installed (EPRI 2011*)

• Relative to Conventional Gas Turbines;• Higher Efficiency

• Use less fuel

• Faster Ramp Rates

Compressed Air Energy Storage (CAES)

* http://www.rmi.org/Content/Files/EstimatingCostsSmartGRid.pdf

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McIntosh, Alabama - 1991

Huntorf, Germany - 1978

Existing CAES Plants

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2017

2018Future CAES Plants

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Larne CAES Project, Northern Ireland

• Planning submission – Q2, 2014

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Advanced Adiabatic Compressed Air Energy Storage for the Integration of Wind Energy, Chris Bullough, Christoph Gatzen, Christoph Jakiel, Martin Koller, Andreas Nowi, and Stefan Zunft, Proceedings of the European Wind Energy Conference, EWEC 2004, 22-25 November 2004, London UK

Adiabatic CAESWaste heat from air compression is recovered in “Thermal Energy

Stores” (TES), to save or eliminate fuel.

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Design Objectives:

• To minimise excessive ‘throwing away’ of valuable thermal energy during charging.

• To eliminate (or reduce) the need to burn fuel during discharging.

• To attain higher efficiencies.

Adiabatic CAES

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Thermal Energy Store (TES)Modelling of Heat Storage & Release

TES Concept

Computed variation in TES temperature with time and

position10

“Round Trip” Efficiency for CAES is Not Simple

Energy Inputs to Plant

1) Electric Power (e.g. surplus wind) input used to compress air during “charging” (€ cost to operator).

2) Natural Gas input needed to re-heat the turbine air (€ cost to operator).

Energy Outputs from Plant1) Electric Power generated by turbine when

“discharging” air (€ income to operator).2) Waste heat from compressor cooling during “charging”

(€0 value).3) Waste Heat from hot gas leaving turbine (€0 value).

Thermal Energy StoreFurther complications for efficiency analysis (time-history).

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Three Designs – Typical Efficiencies & € ratio

1. Simplest Plant, No Recuperator, No Thermal StorageCompressor (cooled) Power Input: 58 MWTurbine Power Output; 330 MWEfficiency (energy ratio): 45%Typical Operating Income ÷ Costs: 1.13

2. With Recuperator, No Thermal Energy StorageCompressor (Cooled) Power Input: 58 MWTurbine Power Output; 330 MWEfficiency (energy ratio): 54%Typical Operating Income ÷ Costs: 1.26

3. With Recuperator & Thermal Energy StorageCompressor (Adiabatic) Power Input: 75 MWTurbine Power Output; 326 MWEfficiency (energy ratio): 64%Typical Operating Income ÷ Costs: 1.25

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Thank You for Your Attention

David J. Timoney

University College Dublin, Ireland

david.timoney@ucd.ie

3rd April 201413