Energy and water have a vital link

The energy-water nexus – the vital link between energy and water – is shaping up to be one of the most important issues of the 21st century.

EarthSky spoke with Dr. Michael Webber, associate director of the Center for International Energy and Environmental Policy in the Jackson School of Geosciences. He explained that it takes energy to use water.

We need energy for water, because we use energy to heat, treat and move water, we use energy to drive pumps that pull water out of the ground, we use energy to treat that water by heating it, and we use energy to bring water to our homes where we use energy to heat it.

It also works the other way, he said. We need water for energy.

We use water for cooling power plants, we use water for mining, oil and gas production. And if we didn’t have that water, we might not have the energy we need.

With his background in mechanical engineering, Dr. Webber tries to figure out how to limit water use in energy production. He explained that power plants – which use lots of water to keep cool – often employ a technique called dry cooling to use less water. It’s the same kind of cooling your car engine has. But, he said, it turns out dry cooling can make a power plant’s energy production less efficient. He said:

And so this is the challenge for decision-makers, balancing these trade offs as they try to try to meet societal challenges for energy and water. Sometimes the best solution is win-win, which is conservation.

If we work hard to solve our energy problems, and we do it the right way, we can solve some of our water problems at the same time, and vice versa. But if we make bad decisions, we might worsen both.

In late March of 2011, Webber testified before the U.S. Senate about the energy water nexus.

The most important, I told them, is that this problem is serious enough and geographically expansive enough that it goes beyond one city, one state, one county, that there’s actually a role for federal engagement. This is an important enough issue that the federal government should be paying attention.

Dr. Webber said he believes the federal government could be especially helpful when it comes to enabling experts to gather, share and analyze water-use data. He described the kind of data-gathering with which he believes the federal government could help most:

Data about where water is used and how it’s used, which power plants pull which water from which basin – that’s actually not known very well, nation-wide. Neither is how much water we use at water treatment plants. So there’s a lot of information that we lack that would be great to get collected from some central repository.

Webber is an expert on the water-energy nexus in the state of Texas, and he talked about the situation there. He said that, while the whole globe is facing limits on water and energy use, Texas is a hotbed of research for the energy-water nexus because it’s got a big energy industry, and also a lot of water constraints.

Texas is more interesting than some places because we have so many power plants, so many people, and so many variability in water concern – water scarce on one side, water rich on the other.

In other words, there is plentiful water in east Texas, but water scarcity in west Texas. Because of air quality concerns, it’s advisable, in one sense, to have pollution-emitting power plants reside in the west of the state. But water constraints make that difficult. Webber said:

We have air quality concerns that might push you to operate power plants in the west where the air is cleaner, but the water constraints in the west make you want to use power plants in the east. This is a difficult tension to overcome, and we’re trying to come up with the methodology to help solve that. It might involved dispatching power from different power plants at different times of year.

He said that while he thinks a lot about power plants and the water they use, he also considers how to best conserve water in Texas, so that more of it can be used for energy production.

We could change the way we use water at our homes. We expend a lot of water on lawn maintenance, for example. And then we use energy to mow. So we could think of switching the types of glasses that grow on our lawns so they use less water in Texas, or even just switching to gravel. We could use reclaimed water for irrigation, or to flush our toilets.

Reclaimed water is water that hasn’t been through a water treatment plant.

We really don’t need drinking water for everything, even though we use it that way. We just need drinking water for drinking and cooking.

Bottom line: Dr. Michael Webber, associate director of the Center for International Energy and Environmental Policy in the Jackson School of Geosciences, sees the energy-water nexus, the connection between energy and water, as one of the most important issues of the 21st century.

June 22, 2012

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