We don’t hear much about the benefits of solar power as a water saver, but solar and other renewables will be critical in providing a steady flow of energy as major droughts become common.
“The future of energy production in the US for the next decades is being decided today,” notes Jigar Shah, founder and former CEO of Sun Edison and a partner at investment fund Inerjys. “Over 70,000 MWs of coal being retired by 2020, and it will be replaced by natural gas, renewables and energy efficiency. Climate change and droughts are forcing public service commissions to take water use into account when planning that future. Given the water scarcity we will be facing, renewables and energy efficiency are leading the way.”
While power plants consume only 4% of our freshwater supplies, they use more than 40% of US freshwater resources for cooling and send it back into lakes and rivers . Each day, big centralized coal-fired, natural gas and nuclear plants use more than 60 billion to 170 billion gallons of freshwater from lakes, rivers and aquifers for cooling. Coal-fired energy plants are responsible for 67 percent of those withdrawals. It requires more water, on average, to generate the electricity that lights our rooms, powers our computers and TVs, and runs our household appliances, than the total amount of water we use insides our homes everyday.
These “water hogs” power plants have not been built to adapt to water scarcity. The heat waves and drought that hit the US in 2011 and 2012 shined a harsh light on the vulnerability of its fossil fuel-powered electricity infrastructure. In 2011, Texas power plant operators trucked in water from remote sites to keep their plants running.
During the summer of 2012, power plants through the US, including the Midwest and Northeast, were forced to reduce operations or shut down. Seven Midwest nuclear and coal plants received permission to put aside environmental regulations and discharge warmer cooling waters that damage water ecosystems.
The US Energy Information Administration (EIA) projects that the US will continue to rely on massive supplies of freshwater for energy as natural gas replace coal-fired energy plants. EIA projections chart limited growth in renewable energy and marginal energy efficiency (see the chart below). However, the National Renewable Energy Laboratory’s Regional Energy Deployment System (ReEDS) has developed a model that considers a bigger role for low-carbon electricity sources and charts their impact for freshwater requirements through 2050. The 2012 report, “The Water Implications of Generating Electricity,” evaluates different water sources and the water requirements of current portfolio of electricity generating plants technologies in the US. The report contrasts the EIA scenario with others, including one scenario (below), the report assumes aggressive deployment of energy efficient technologies and buildings. In that scenario, US electricity demand would drop 20% by 2035 and 35% by 2050 versus the reference case, while generation from renewable energy technologies (wind, solar, geothermal, biomass and hydropower) would increase from 10% in 2010 to 50% in 2035 and 80% by 2050.
The report estimates that aggressive implementation of renewable energy and energy efficiency would save 1.1 trillion gallons of water per year. More importantly, however, this wide base of decentralized energy that would be independent of water supply would ensure energy resilience during the droughts and water scarcity shocks that we expect in the future.
The short-term future of water will include scarcity shocks. We don’t know where they will hit, but it only takes another dry summer to bring on a more brutal season of plant shut downs and energy brown outs. In the aftermath, the cost of water-intensive fossil fuel energy will be much clearer.