It’s well documented that clean coal technologies (aka “New Generation Coal“) require increased coal consumption to produce the additional energy required for processes related to reducing emissions, but often overlooked in the clean coal controversy is the issue of water.
A report entitled Water and the electricity generation industry: Implications of use, prepared for Australia’s Water Commission and the Australian Government Department of Resources, Energy and Tourism warns that water-cooled, low-emission thermal power plants are likely to be significantly more water intensive than current coal-fired power plants.
The report states coal-fired power plants incorporating carbon capture and storage (CCS) could be one-quarter to one-third more water intensive.
Furthermore, as solar thermal and geothermal power plants are likely to operate at lower thermal efficiencies than conventional coal-fired steam turbines, they are also likely to have a higher water intensity.
Water is already a precious resource in Australia and accounts for about 1.4 per cent of total national water consumption. In coal fired power stations water is used for generating steam to drive steam turbines, for cooling the exhaust steam and for other operations including ash disposal.
The report recommends that in light of the need to reduce carbon emissions and the impact on water demand for cooling in power stations, priority should be given to focusing research and development in Australia on water management and efficiency in electricity generation.
Dry cooling can reduce water consumption of thermal power stations by more than 90 per cent, but reduces the sent-out efficiency (the ratio of fuel consumed to energy sent out from a power station) of power plants by around two to three per cent and increases carbon dioxide emissions of coal-fired power plants by up to six per cent. This would also see an increased consumption of coal to make up for the shortfall in energy output.
Part of the solution to the water issue is already available – solar panel based solar farms, as these require no water whatsoever be consumed in the process of generating electricity.
