Bryden, Ian

Harrison, Gareth

Barbour, Edward

Engineering and Physical Sciences Research Council (EPSRC)

2013-11-19T15:16:10Z

2013-11-19T15:16:10Z

2013-11-28

Renewable Energy is by nature intermittent and matching the supply of energy to specific time dependent demand poses huge challenges. Energy storage is a useful tool in handling this temporal disparity, although except for regions very suitable for pumped hydroelectric storage schemes, it suffers from being technically difficult to implement and costly as a result. This study investigates the potential benefits offered by various scales of energy storage to different types of renewable energy generation. It also explores the economic drivers behind energy storage operating as part of an electricity spot market. A stochastic optimisation algorithm for determining the maximum possible arbitrage revenue available to energy storage devices is presented and schedule of operation of storage acting in this manner is analysed. The schedule of operation for maximising the revenue is compared to the schedule of operation for minimising the fuel cost to the network and it is demonstrated that because prices are more volatile than the demand which drives them, storage devices do not always act to decrease the fuel cost to the network. It is shown that storage behaving in the right manner can offer significant benefits to electricity systems, and increases the usage of base-load generation, reducing peak electricity demands and the need for expensive peaking plants. The value of storage also increases as the penetration of renewable energy generation increases, although the current electricity market framework is perhaps not the best way to encourage this behaviour. Advanced Adiabatic Compressed Air Energy Storage (AA-CAES) is also identified as a theoretical storage option which deserves further scrutiny. Using thermodynamic modelling the efficiency of this type of system is estimated in the range of 63-67%, and we suggest that this may be increased closer to 73% by using direct contact heat exchangers rather than indirect contact heat exchangers (and a separate thermal fluid), as described in the currently available literature. However, dealing with large pressure ranges (leading to large variations in pressure ratios) encountered in the expansion process is a problematic area which will have to be resolved before this type of system can be constructed with “off-the-shelf” components. Some small scale experiments are used to gain valuable insights into a AA-CAES system. While these suffer from a very low overall efficiency, they highlight the effect of variable pressure ratio on expander efficiency. We conclude that AA-CAES is thermodynamically sound and will be achieved one of two ways: either through the construction of expanders that can work with high efficiency over large pressure ratios, or by resolving the engineering issues with maintaining a constant storage pressure.

http://hdl.handle.net/1842/8189

en

The University of Edinburgh

E. Barbour and I. G. Bryden. Energy storage in association with tidal current generation systems. Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy, 225(4):443–455, June 2011. ISSN 0957-6509. doi: 10.1177/0957650911399014.

E. Barbour, I. A. G.Wilson, I. G. Bryden, P. G. Mcgregor, A. Mulheran, and P. J. Hall. Towards an objective method to compare energy storage technologies : development and validation of a model to determine the upper boundary of revenue available from electrical price arbitrage. Energy & Environemntal Science, (5):5425–5436, 2012. doi: 10.1039/c2ee02419e.

S. Gill, E. Barbour, I. Wilson, and D. Infield. Maximising revenue for non-firm distributed wind generation with energy storage in an active management scheme. IET Renewable Power Generation, 2013.

energy storage

intermittent

Advanced Adiabatic Compressed Air Energy Storage

AA-CAES

electricity market

Investigation into the potential of energy storage to tackle intermittency in renewable energy generation

Thesis or Dissertation

Doctoral

PhD Doctor of Philosophy