Big water losses in carbon drain

3 December 2010

The Canberra Times

By Jamie Pittock and Karen Hussey

It is a simple truth that all forms of energy production and carbon capture and storage require water and usually a lot of it. Yet few government and industry policies on climate change and energy have considered the relationship with water, and consequently many climate change responses risk running Australia dry.

The looming threat from climate change has prompted many nations to change their policies in favour of lower carbon energy sources and carbon capture and storage or CCS. Placing a price on greenhouse gas emissions and mandatory renewable energy targets is about creating incentives for the development of new technologies and encouraging greater reliance on different energy sources. These all require water.

Currently, in most industrial societies, large volumes of water are withdrawn for use in cooling thermal power stations, and while most of the water is returned to the environment, it is usually of lower quality, and alters natural water flows. The environment suffers as a consequence. Through evaporation or other losses, 1.4 per cent of Australia's national water diversions are actually consumed in power generation (evaporated or transformed in other ways). This may not sound like much water, but power generators are concentrated in small regions that are water scarce, such as the Hunter Valley in NSWs and the Latrobe Valley in Victoria.

Water scarcity has already threatened power generation during drought. CCS of greenhouse gas emissions from fossil fuel power stations would increase their demand for water by around a quarter. Water is needed to cool the solvents used to capture the pollutants, and as the carbon capture process uses about 15 per cent of the power generated, more power needs to be produced. Climate change policies favour power generation from gas as it produces only 40 per cent of the greenhouse gas pollution of coal and oil. The boom in coal seam gas production in Australia and the United States also has its downside, with vast aquifers being drained just to access the resource.

Renewable energy technologies are also thirsty. Production of biofuels from crops such as sugar cane consumes more water than any other energy source. Thermal solar, biofuel and geothermal power stations require water, and the proposed location of many of these power stations in arid areas increases the challenge for sustaining water supplies. While air- cooling technology exists for thermal power stations, this comes with an increased infrastructure bill and an energy efficiency penalty of up to 10 per cent.

While natural sources of energy such as sunlight and wind use little water directly, as their capacity increases energy storage capacity is required to match their intermittent production with demand. Pumped storage hydropower is the currently available technology, involving use of excess power to pump water uphill for later use to meet demand peaks. If developed, poorly new pumped storage projects could further damage our freshwater ecosystems, but if deployed well, then renovation could reduce the impacts of old, environmentally damaging dams. Ironically, as water becomes even scarcer (in part because of climate change) the measures adopted to secure water supplies require increasingly more energy, for instance, to desalinate seawater and pump water over longer distances.

Policies of all of Australia's political parties to encourage farmers to plant trees to store carbon highlight a disconnection between policies on climate change and water. Young, fast-growing eucalypts transpire a lot of water. In one study of the Macquarie River in NSW, afforesting 10 per cent of the headwaters was forecast to reduce river inflows by 17 per cent.

The National Water Commission and Murray-Darling Basin Authority are calling for governments to regulate such ''inflow interception activities'', which currently consume the equivalent of a quarter of issued water entitlements nationally. Yet other government agencies are proposing measures to expand carbon afforestation without apparent consideration of water consumption. Examples from the US suggest ways in which these sectors can be better coordinated to secure energy and water supplies and respond to climate change.

Integrated planning is one answer. In an attempt to produce better integrated policy, for instance, the University of Texas and its state government have collaborated to produce an online system that enables decision-makers to match the water demand of different energy generation technologies to the available water resources. Iterative decision-making is another solution. The system of relicensing of hydropower stations in the US every 30 years has enabled many dams to be re-engineered to meet modern social, economic and environmental standards, reduce impacts, and in some cases, to increase power production.

In our responses to climate change, Australian institutions are creating new silos that overlook essential interrelationships, and the result is the adoption of policies that exacerbate key problems. Water, energy and climate change are inextricably linked and it is time Australian businesses and governments integrated management of these sectors.

Jamie Pittock leads the Australia and United States Climate, Energy and Water project for the US Studies Centre and Dr Karen Hussey is co-chair of the Australian National University Water Initiative and leads the ANU-COST European initiative on climate, energy and water. The US Studies Centre and the ANU have established an Australia and United States climate, energy and water project to clarify the conflicts and synergies between energy and carbon sequestration technologies and water supplies, and to identify solutions that governments and businesses can apply. Case studies and solutions from Europe, the US and Australia will be debated at our climate, energy and water forums in Canberra, Melbourne and Sydney from December 2-8.

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Tags: Australia United States Climate Energy Water Nexus Project, Climate Change, Dow Sustainability Program, Jamie Pittock

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