Sustainability and energy development: influences of greenhouse gas emission reduction options on water use in energy production.

Climate change mitigation strategies cannot be evaluated solely in terms of energy cost and greenhouse gas (GHG) mitigation potential. Maintaining GHGs at a "safe" level will require fundamental change in the way we approach energy production, and a number of environmental, economic, and societal factors will come into play. Water is an essential component of energy production, and water resource constraints will limit our options for meeting society's growing demand for energy while also reducing GHG emissions. This study evaluates these potential constraints from a global perspective by revisiting the climate wedges proposal of Pacala and Socolow (Science2004, 305 (5686), 968-972) and evaluating the potential water-use impacts of the wedges associated with energy production. GHG mitigation options that improve energy conversion or use efficiency can simultaneously reduce GHG emissions, lower energy costs, and reduce energy impacts on water resources. Other GHG mitigation options (e.g., carbon capture and sequestration, traditional nuclear, and biofuels from dedicated energy crops) increase water requirements for energy. Achieving energy sustainability requires deployment of alternatives that can reduce GHG emissions, water resource impacts, and energy costs.