Water and energy are deeply intertwined: production of electricity requires water, and water supply requires electricity. Demand for both is growing, while supply is constrained by limited resource availability, high costs, and the impacts of climate change. These linked problems are sometimes referred to as the “water-energy nexus.” This study looks at the situation in the U.S. West.

The authors modeled long-run scenarios for the eleven-state Western Electric Coordinating Council, stretching from the Pacific coast through Montana, Wyoming, Colorado, and New Mexico. They project power plant construction and operation, focusing on costs, water use, and greenhouse gas emissions, from now through 2100.

In each energy scenario, demand is based on state population trends, and on temperature forecasts from climate scenarios. Supply is initially based on existing power plants, shifting toward a new fuel mix as new plants are built, with different fuel mixes depending on policy choices.

The authors defined four scenarios: business as usual (BAU); water reduction; carbon cap; and both water and carbon limits. The most surprising conclusion was the relatively small difference between scenarios in total water consumption. The maximum impact, or difference between the most and least water-intensive energy scenarios, was less than 1.2 million acre-feet of water per year by 2100 for the eleven-state region as a whole.

The model also shows the range of carbon and water prices that could drive the market toward low-carbon and low-water choices. A carbon price of $70 per ton of carbon dioxide makes the carbon-reducing scenarios lower in cost; a water price of $4,000 to $7,000 per acre foot is needed to make the water-conserving scenarios lower in cost. The latter is well beyond the range of current costs for virtually all water transactions.

This report is part of a package that also includes The Last Drop: Climate Change and the Southwest Water Crisis and California Water Supply and Demand: Technical Report.

Download the report (pdf, 1.24Mb)