10 July 2014 — BRIEF: Technology, policies or plans that aim to reduce carbon emissions should also take factors such as water use into account, especially in dry countries like Australia, according to research out of Monash University.

A more integrated approach might make some options considerably more attractive than others, Dr Philip Wallis of Monash University in Australia and colleagues found, in an article published in Climatic Change.

The researchers considered Australia to show how water use influences the appeal of certain preferred mitigation options.

They analysed 74 options that were ranked in the influential “Low Carbon Growth Plan for Australia” in 2010, and together could help Australia cut its 2000 emission levels by 25 per cent by 2020.

The options varied considerably as to how much water each one uses. Energy efficiency measures were found to reduce water consumption, as did measures in the power sector generally.

Renewable options such as solar thermal power only moderately impact water consumption. Further reductions are possible by tapping into existing power-related water supplies or using air or salt-water cooling.

Wind power, biogas, solar photovoltaics, energy efficiency and operational improvements to existing power sources can reduce water demand by offsetting the water used to cool thermal power generation. This could help save nearly 100 million cubic metres of water in Australia annually by 2020.

Wallis believes the technologies and locations used for renewable energy should appropriately reflect water constraints.

Land-based mitigation measures such as “carbon farming” for carbon credits and the suggested reforestation of land use the most water. This is likely to influence catchment water yields, depending on where planting takes place.

Although such plantings can also help reduce salinity, erosion, and flooding, the researchers believe some of these endeavors should be reconsidered, either in the scale of plantings, their location, or the carbon price required for these to be cost effective.

“This integrated analysis significantly changes the attractiveness of some mitigation options, compared to cases where water impacts are not considered,” Dr Wallis said. “This Australian case shows that mitigation measures that carry water co-benefits, especially energy efficiency, ought to be pursued.”

Read the full paper.