29 May 2012: A new report by the Stockholm Environment Institute (SEI) discusses water use of conventional and renewable sources for electricity production, and finds that, based on a case study in California, low-carbon energy sources might require considerable amounts of water, and offers recommendations for improvements.

The report discusses trade-offs between electricity generation and water use and ways in which climate change and hydrologic changes impacts electricity generation, especially in areas where climate change may decrease the availability of water. The report also examines conventional technologies’ water use in electricity production as well as the water requirements associated with renewable energy technologies.

The main conclusions of the report are drawn from a case study of water use for electricity generation in California. The study focuses on the state’s renewable energy portfolio standard (RPS), which intends to increase the share of renewable energy in the state’s electricity mix to 33 per cent by 2020, and the water and emissions implications thereof. The study finds that under a business as usual scenario, greenhouse gas (GHG) emissions, water withdrawals and water consumption (i.e., water that is not available for return or reuse to the source) increase, while under the RSP, GHG emissions and water withdrawals decrease, while water consumption increases.

The report then investigates a RPS+Technology scenario, including using more photovoltaics and less solar thermal power, and incrementally switching once-through to wet-recirculating and dry-cooling systems. The report finds that under this scenario both water withdrawals and consumption decrease, while increased GHG emissions, due to decreased energy efficiency, could be compensated for by using carbon capture and sequestration. The reports ends with policy and technological recommendations, including on: efficiency improvements and electricity demand reductions; water recycling and re-use; and renewable energy storage technologies. [Publication: Water for Electricity: Resource Scarcity, Climate Change and Business in a Finite World] [Publication: Policy Brief: Water in a Low-Carbon Economy: Resource Scarcity, Climate Change and Business in a Finite World]