The Regional Energy & Water Supply Scenarios (REWSS) model, part II: Case studies in Pennsylvania and Arizona

• A new model is presented to calculate annual environmental impacts of energy and water supplies.
• Model data is taken from existing regional data and life-cycle assessment studies.
• Uncertainty is included through Monte-Carlo methods.
• The model is validated using greenhouse gas emissions for Pennsylvania and Arizona.

Water and energy are interconnected resources that face regional supply limitations and contribute to environmental issues such as climate change. Pennsylvania and Arizona are creating policies to steer large transitions in their energy and water sources, respectively. This paper provides case studies using the newly developed Regional Energy & Water Supply Scenarios (REWSS) model to explore potential impacts of different pathways in these two states. Part I of this work discusses model structure, procedure, and validation.Pennsylvania has become a major producer of shale gas, but the potential for greenhouse gas emissions reductions from shale gas are uncertain. Results show only small decreases in GHG emissions if shale gas is used for electricity due to limited reductions in transportation and heating-related emissions. PA results also highlight potential water for energy issues around biofuels if irrigated feedstocks are used. Arizona faces water supply issues due to population growth and overused groundwater. Scenarios examined focus on replacing groundwater with imports or desalination. AZ results show that the use of desalination could show marginal increases in GHGs and energy consumption (2%), but the widespread deployment of solar power to offset additional GHGs would likely have a high upfront energetic cost.