Small compressed air energy storage systems

Herriman, Kayne (2013) Small compressed air energy storage systems. [USQ Project]

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Abstract

The storage of energy is emerging as a greener way to support our existing electricity networks and improve the stability of our grids, as we step forward into a cleaner future and becomes more dependent on intermittent renewable generation sources.

Australia is seen to be blessed with an abundant of renewable energy resources and it has been said that Australia is the Middle East of renewables. These 'free' resources substantially exceed Australia’s total energy demand, both currently and into the foreseeable future.

Most energy storage systems require the useful energy to be converted from its initial state into another form, which is more suitable for storage. When ready to use, it's then converted back into a useful form. With each conversion there are losses associated which affect efficiency, for this reason efficiencies of are not achievable.

Compressed Air Energy Storage (CAES) is not an unproven technology and on a large scale there are two existing CAES plant in the world. The first plant ever built was in Huntorf Germany, which was commissioned in and capable of producing for two hours. The second was in McIntosh Alabama USA, which was commissioned in and capable of producing 190 MW for 26 hours (Energy C. , 2012). Small CAES technology would dramatically lighten the loads on networks, help people who cannot connect to a power grid and serves as an advantage to those people living in developing countries.

A main goal of dissertation was to produce some correlation between the theoretical analysis and the data from dyno testing. The isothermal and adiabatic equations used are 'ideal' equations which are never actually achieved by physical machines. It was found that the dyno results were substantially lower than the ideal equations which were used to calculate the stored energy and specific power. This is because the theory does not take into account losses like compressor mechanical and storage tank thermal losses, compressor and air motor thermodynamic efficiency, air motor mechanical efficiency and friction and flow losses.

It is said that the most common solution for small to medium storage is batteries, although very good at storing energy they are very hard to recycle and are very dangerous if not used correctly. Yet the benefits of compressed air over electric storage are the longer lifetime of pressure vessels and materials are entirely benign as well as life time costs are potentially lower.

Like solar energy, air is a clean and an abundant resource with specific gas characteristics, which allows it to be compressed and expanded without any effect apart from the exchange of heat with the immediate environment. This heat energy could be captured and used for heating our homes, for hot water, cooking or even generating electricity. Thus, CAES is a simple and effective way of storing energy for later use.

With a renewable energy target of 20% or 45,000 Gigawatt hours (GWhr) by 2020, there is no better time like the present to harness the energy to provide a cleaner future for our children’s children.


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Item Type: USQ Project
Item Status: Live Archive
Faculty / Department / School: Current - Faculty of Health, Engineering and Sciences - School of Mechanical and Electrical Engineering
Supervisors: Bowtell, Leslie; Malpress, Ray
Date Deposited: 06 Mar 2014 20:51
Last Modified: 07 Mar 2014 00:22
Uncontrolled Keywords: compressed air; energy storage; renewable energy; sustainable
Fields of Research : 09 Engineering > 0906 Electrical and Electronic Engineering > 090608 Renewable Power and Energy Systems Engineering (excl. Solar Cells)
Socio-Economic Objective: B Economic Development > 85 Energy > 8506 Energy Storage, Distribution and Supply > 850602 Energy Storage (excl. Hydrogen)
URI: http://eprints.usq.edu.au/id/eprint/24651

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