Sustainability assessment of hydroelectricity

Hydroelectricity is an established power generation technology with over 100 years of commercial operation. In 2007, over 3,000 TWh of electricity were produced in the OECD by hydropower, representing 15.5% of OECD net electricity production. The worldwide technical potential of hydropower is estimated at approximately five times current production levels.

Conventional hydropower is a simple conversion of potential energy into electricity, leading to high efficiencies. It is a reliable and proven renewable energy technology, with low operating costs and long plant life. Hydropower is also the only renewable energy technology currently available to achieve base load and peak load electricity production. Hydropower plants are highly capital intensive, with the construction of the darn the most significant cost. Darn construction requires large areas of land to be flooded, potentially destroying forests, towns and ecosystems. The environmental impacts of dam construction can be significantly different between plants, dependent upon the size and location. Therefore, site specific assessments comparing the benefits against environmental footprint are essential for increasing the globally installed capacity of hydroelectric power.

This chapter discusses parameters that define the sustainability of hydroelectric power technology. The sustainability of hydropower has been assessed according to economic, environmental and societal impacts. The key indicators of these impacts have been defined, on a per kilowatt hour basis, as the price, efficiency, carbon emissions, water use, land use, availability, limitations and social impacts. Each of these impacts has been compared, to conclude which are the most sustainable aspects of hydropower.

The primary findings are that hydropower is already sustainable with regard to cost, efficiency and availability. Water use is typically positive, with hydropower dams able to benefit the community through flood control, irrigation, recreation and tourism. Carbon emissions vary greatly according to local conditions. Land use is one of the least sustainable aspects, since traditional hydropower has one of the highest direct land use requirements of any form of electricity generation.