Don't Forget Water in Our Energy Future

Posted on November 17, 2009 | Filed Under: Global Warming , Water Supply

Will Hewes
Climate Policy Coordinator

On the road to a clean energy future, there are many road blocks. There is political resistance driven by those that benefit from the current system. The enormous financial cost of transitioning to new power sources and meeting rising energy demands in an era of ballooning deficits and tightening budgets also presents a major challenge.

But one constraint that is often overlooked is the need for large amounts of water in places where supplies are already short. Given rising populations and over-allocated water resources, the construction of a renewable energy infrastructure will inevitably bump up against water constraints.

Energy developers in the west are already learning this lesson. Just yesterday, Solar Millennium, a German developer that is proposing a new solar thermal plant near Las Vegas, announced that it would alter its plans in order to reduce water consumption. Solar thermal plants use the sun’s rays to heat water and drive turbines. Wet cooling allows the heat to escape through evaporation, while dry cooling employs fans and heat exchangers and keeps the water from escaping. The latter uses 90% less water but is typically 5% more expensive to build while also reducing energy output 5%. For a technology that is already struggling to be cost competitive with dirtier fuel sources, these additional costs can be prohibitive.

From biofuels to solar energy to carbon capture and sequestration, water availability will be a key constraint on the new technologies that are being proposed as a solution to our energy challenge. Solar energy installations are often sited in deserts where water is scarce. This isn’t to say that traditional forms of energy production don’t have their own problems; thermoelectric power plants are responsible for 41% of all water withdrawals in the country and often do profound damage to local waterways. But a renewable energy infrastructure will have to be built in a more water-scarce future as the climate shifts and water resources are further depleted by overuse.

Of course renewable technologies such as wind and solar will be essential if we are going to avert the climate crisis. Global warming is the single largest threat to our water resources and our communities, and we must take immediate action to limit emissions. But we have to be aware that technology and politics aren’t the only obstacles to a more sustainable energy infrastructure. It will take careful planning of new energy technologies as well as improvements in how we manage water resources in other sectors. Protecting and restoring the ecosystems that provide clean water and increasing conservation and efficiency will go a long way to ensuring a safe and consistent supply of clean water in the future.

Anne Castle, the Interior Department’s assistant secretary for Water and Science put it best when she recently commented, “We need to avoid having our new energy economy run smack into the buzz saw of water shortage.”

Policymakers, energy developers, and water managers should keep this in mind.
 

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