A press release, issued by the government of the state of New South Wales (NSW) in Australia, says water releases from the state’s dams could be used to provide renewable, pollution-free electricity, as well as eliminate the production of more than 260,000 tonnes of carbon dioxide each year.

The Sustainable Energy Development Authority (SEDA), a NSW government agency, has identified 32 existing dams in the state as potential small hydro sites.

Work has already started on the construction of a mini hydro project at Toonumbar dam, operated by State Water, an agency under the Department of Land and Water Conservation. At Toonumbar power is to be generated using a pump modified to operate as a turbine, with an efficiency of about 82%. This turbine is directly connected to an asynchronous generator which avoids synchronising, voltage regulating and other equipment which a synchronous generator would require.

The Toonumbar project will be automatically controlled, with the power output determined by the water level in the dam.

When commissioned it is expected to avoid the burning of 200 tonnes of coal and the production of 400 tonnes of greenhouse gases each year. Each megawatt of electricity generated at a hydroelectric plant prevents the production of one tonne of carbon dioxide for each hour it operates.

Small hydro plants at Burrinjuck, Glenbawn, Cope-ton, Keepit, Wyangala and Burrendong dams are generating a combined total of 71MW of electricity — enough to meet the needs of about 35,500 homes. With work now under way at Toonumbar dam, State Water is focusing on another three hydro power projects which are expected to begin construction in coming months at Brogo dam near Bega, Lostock dam near Maitland and Glennies Creek dam, near Muswellbrook. Along with these dams, a further six weirs on the Murrumbidgee are expected to begin generating hydroelectricity next year.