Most forms of power generation, especially coal, oil, and natural gas, require large amounts of water. The US Geological Service says nearly half of the nation's water consumption is used in creating electricity, an astonishingly high number. Coal and petroleum-based energy are among the most water-intensive, as water is used every step along the way, from extraction to refining as well as in production.
But, environmentalists shouldn't get too smug here. Concentrated Solar Power (CSP), which reflects the heat of the sun to a tower to power turbines, uses more water per MWh produced than coal. Plus, CSP generation is generally done in deserts, using precious aquifer water or by having it piped in, which is inefficient and not at all carbon-neutral. Several grid-scale CSP sites are planned for California deserts, all part of the state's ambitious goal to have 33% renewable power by 2020. But will such sites have enough water, as well as get by environmental restrictions and probable NIMBY opposition?
Creating biofuel is a worthwhile goal, as it allows California to create alternatives to petroleum within its own orders, with no importing needed from other countries. But biofuel requires water too. Corn ethanol, in particular, is a massive water hog. But cellulosic ethanol (creating biofuel from plant and animal leftovers, not from crops grown specifically for biofuel) also requires large amounts of water. Algae biofuel shows great promise but like CSP, is done in deserts and needs quite a lot of water too.
Many power plants, including CSP, are steam-based. Heated water is often injected back into the ground with quite possibly damaging side effects. The relatively new technologies of fracking and oil shale involve pumping toxic chemicals deep underground, something which cannot avoid impacting water sources.
Here's another astonishing fact: 20% of California's energy consumption is used to deliver water, mostly for sending water to farmland and to the Los Angeles / Orange County /San Diego megalopolis. Thus, we have the spectacle of nearly 50% of our water being used to create power, and 20% of that power is used to move water around the state. This hardly seems sustainable, more like running faster and faster to stay in the same place.
The obvious answer here is conservation. Cutting back on energy usage saves water. The reverse is also true. Reducing water usage lowers energy needs. Just imagine what an initial 5% reduction in both would do. Since they feed off each other, such an initial reduction would probably result in much more than 5%. Further, such reductions should be relatively painless. Smarter appliances and an upgraded grid, plus new methods to reuse water in power plants could go a long way here.
Wind power, solar photovoltaic, and solar updraft towers do not require water. The technologies should be encouraged, especially in California and the Southwest, where water wars abound. But these forms of renewable energy can't do it alone. Far more power is needed besides what they can provide. Let's hope they use as little water as possible.