Loading...
Activism

Energy Takes Water, Water Takes Energy

A water mill in Brazil (photo by Angelo Leithold).How do we meet the world’s future energy demands? Not an easy question, but it gets even more complicated when you factor in another critical need: water.

While water hasn’t always been factored into energy discussions — or vice versa — the two are “inextricably linked,” according to Sandia National Laboratories. That’s why researchers there are working to develop an advanced modeling tool that will help people better understand their energy and water needs in one neat, if complex, package.

It makes lots of sense, once you think about it. Purifying water for drinking, pumping water into homes and fields, and reclaiming water for reuse all require energy. And generating energy takes lots of water, whether indirectly by coal-burning power plants or nuclear reactors or directly by hydropower. According to Sandia Labs, the U.S. uses about 140 billion gallons of water per day to generate its electricity. Even though most of that water can be immediately reused, as opposed to the water used in agriculture, that still amounts to more than 40 percent of all the fresh water used by the nation every day.

As energy demands continue to rise, water shortages around the globe expand and climate change aggravates both, the complicated interplay between energy and water will become more important than ever for us to understand.

Take, for example, the rush to build desalination plants to turn salt water into drinking water as existing fresh water sources dry up. Desalination is energy-intensive; in fact, one study estimated that it takes 10,000 tons of oil a year to put out 1,000 cubic meters of desalinated water per day. Multiply that by the 13,080 desalination plants currently operating around the world, and the energy costs are clear.

Sandia researchers hope their new interactive energy-water model will give decision-makers across the board access to better information on how to plan for the future. The system, now in its second year of development, will eventually help answer questions about regional shortfalls, the tradeoffs involved for different energy and water sources, environmental and economic costs, and potential consequences. It’s a tall order, but one well worth trying to achieve.

“The challenge will be to have enough data to tell a story,” said Peter Kobos, a Sandia researcher handling energy modeling. “We think we do. If not, we’ll identify gaps and address them as the project progresses.”




6 comments
  1. Klaus

    Hi,

    You’ll find that the amount of water used depends on the thermal efficiency. And thermal efficiency depends on the temperature differences you can work with. Current generation nuclear power plants are typically pressurized water or boiling water reactors. This limits their thermal efficiencies to something like 30%. However, new Gen VI reactor designs operate with higher temperatures and therefore quite higher efficiencies. This reduces their cooling water requirements to below any other heat based power production system. Some proposals even do completely away with cooling water requirements, as they can use air-cycle turbines to drive the generators.
    But I doubt they will be build in the USA because of the prevailing climate against anything to do with nuclear power.

    – Klaus

  2. Shirley Siluk Gregory

    Hi Klaus. You’re right: nuclear power isn’t the only power source that requires a steady supply of water. However, I’m guessing the amount of water relative to the amount of energy produced differs for each type of power source. I’ll see if I can find any data to that effect.

  3. Klaus

    Hi,

    I think there is a misunderstanding here, caused mainly by the way this issue is represented in the media. The amount of water needed for energy production from ANY heat source is INDEPENDENT of the way the heat is produced. It does not matter if it’s coal, solar thermal, geothermal, nuclear, oil or gas.
    It is structly a result of using a steam cycle. Coal plants, oil burning plants, geothermal plants (if there were any big enough) ALSO would have to shut down or reduce power output during drought conditions. However, different to coal, geothermal and solar thermal, nuclear plants can be located where there’s always plenty of cooling water available. Namely at the coasts. Geothermal plants need to be located in specific locations. Solar thermal plants typically are located in desert regions, where little water is available in the first place, limiting their possible size. And coal plants tend to be localized near coal sources, as otherwise transport costs for the huge amounts of fuel needed would be too large.
    But in the media it is always presented as if only nuclear plants need cooling water.

    – Klaus

  4. Shirley Siluk Gregory

    Thanks, Tim. Yes, the whole water issue is a special concern if we’re going to consider upping nuclear power to help curb greenhouse gases.

    I’ve touched on the “pro” side of nuclear power recently, and will soon address the “cons,” one of which is water. Remember, for example, that during the killer heat wave in Europe a couple of years ago, France experienced problems with its nuclear plants because the local water sources had become too warm to adequately cool the reactors.

  5. Timothy B. Hurst

    You are absolutely right about this, Shirley. This is a very important issue that is not raised enough in the big energy debates – especially in terms of nuclear’s water needs. If nuclear is going to be accepted as a viable source of electricity by segments of the green community, one of the most prominent issues will be the water issue.

Leave a Reply

Your email address will not be published. Required fields are marked *