Opportunities and Threats of the Water/Energy Nexus Doug Kenney, Ph.D. Director, Western Water Policy Program Getches-Wilkinson Center for Natural Resources, Energy and the Environment University of Colorado Law School Urban Water Institute Palm Springs, CA February 20, 2013

The Water/Energy Nexus: General Statistics It takes water to make energy: In 2005, the nation’s thermoelectric power plants withdrew as much water as farms did, and more than four times as much as all U.S. residents (UCS) Consumption is much lower (< 5% of withdrawals) Huge regional variations (due to fuel choices and cooling technologies) It takes energy to manage water: In California, water management and use consumes 19 percent of the state’s electricity, 30 percent of its natural gas, and 88 billion gallons of diesel fuel every year (CEC). In Southern California, its not unusual for water management to require 2,000 – 3,000 kWh/acre-foot. (As a reference, ocean desalination is roughly 4,000 kWh/acre-foot.)

The W/E Nexus in the News Shutdowns and brownouts prompted by cooling water levels too hot or too low to safely operate nuclear and coal-fired generators in the Midwest. Reduced hydroelectric generating capacity in the West. Deepening civic disputes over shrinking water supplies in Texas between thirsty cities and utilities that wanted to construct new coal-fired plants. Farmers outbid by “frackers” for surplus M&I supplies in Colorado

And it Could Get Worse (the “threat”) Water for Energy ◦ In 2006, the Energy Information Administration (EIA) predicted water consumption by power plants would double by 2030 ◦ An oil shale boom in western Colorado could require 378,000 acre-feet/year (WRA) Energy for Water ◦ The Southern Delivery System project (serving Colorado Springs) has an energy intensity equivalent to seawater desalination (WRA) Water Impacts: Greater Competition, Scarcity, Increased Costs, Environmental Impacts, …

Or Better (the “opportunity”) The energy sector (electricity generation) is changing at an unprecedented rate; some of these changes are water friendly ◦ Since 2005, the ratio of energy generation from coal versus natural gas went from nearly 3:1 to 1:1 Further manipulation of ongoing changes is possible and perhaps likely given climate change mitigation concerns These changes could benefit the water sector

Water Demands of Electricity Generation

UCS EWS Preliminary Findings Energy and Water in a Warming World (EW3) project of the Union of Concerned Scientists Focus of current work is impact on electricity generating scenarios on water resources Clemmer, S., J. Rogers, S. Sattler, J. Macknick, and T. Mai “Modeling low-carbon US electricity futures to explore impacts on national and regional water use.” Environmental Research Letters ( ).

4 Electricity Generating Scenarios (1) Reference Scenario (BAU) ◦ Extrapolates impact of current regulations and expected market forces (2) Carbon Budget ◦ 170 gigatons (presumably sufficient to cap atmospheric CO2 at 450 ppm) (3) Carbon Budget + Nuclear and CCS Coal (4) Carbon Budget + Efficiency & Renewables

U.S. Electricity Generation Mix (TWh) PV CSP CoalCCS Utility PV Efficiency (# 1)(# 2) (#3)(# 4)

Water Withdrawals (National) Figure 3. National-level water withdrawal results for four electricity scenarios. Scenario 1, reference case; scenario 2, carbon budget, no technology targets; scenario 3, carbon budget with coal with CCS and nuclear targets; scenario 4, carbon budget with efficiency and renewable energy targets.

Water Consumption (National) Figure 5. National-level water consumption results for four electricity scenarios. Scenario 1, reference case; scenario 2, carbon budget, no technology targets; scenario 3, carbon budget with coal with CCS and nuclear targets; scenario 4, carbon budget with efficiency and renewable energy targets.

Water withdrawal results (in billion gallons per year) for 2030 (blue bars) and 2050 (red bars) by HUC-2 region for electricity Scenarios 1–4; scenario 1, reference case; scenario 2, carbon budget, no technology targets; scenario 3, carbon budget with coal with CCS and nuclear targets; scenario 4, carbon budget with efficiency and renewable energy targets; y-axes have different scales and are for intra-region comparison purposes.

Water Withdrawals (Southwestern US)

Water Consumption (Southwestern US)

Hypothetical Colorado River Water Savings (surface water only) ** DRAFT **

Scenarios: (2) (3) (4) (1) ** DRAFT ** Colorado River Basin

Challenges (Why Is It So Hard to Do the Right Thing?) The energy sector may not have strong incentives to pursue “water friendly” strategies in regions where they can outcompete agriculture for water in the marketplace. Conservation of either resource (water or energy) can be unpopular if benefits are perceived as going to others. Answer: Legislate it; require it. And do so in the name of reduced social conflicts and cost savings. [Preliminary results suggest the most water-friendly pathways are the least cost.]

Summary The rapid changes in the electricity generating sector will have significant implications for water resources Those impacts can be positive or negative, and can vary significantly from region to region Conservation and water-friendly renewables are the obvious tools for taking advantage of the water/energy nexus In most cases, conservation-based management strategies (for energy and water) are likely to be cost-effective

Thank You For more information, contact me directly: Doug Kenney (303) And please remember that this data is preliminary and should be used cautiously.