A Thirst for Power: The Water-Energy Nexus

But here’s what’s really shocking: water and energy are connected and highly interdependent. Simply put, we need water for our energy systems and we need energy systems for our water. Here are some quick facts to prove it:

  • Ninety percent of global electricity is generated by boiling water to create steam that spins turbines. It’s water-intense!
  • In the United States, more freshwater (41 percent) is used to cool power plants than for any other use.
  • About 8 percent of global energy generation is used for pumping, treating, and transporting water.
  • By 2035, global energy consumption is expected to increase by 50 percent, increasing water consumption by 85 percent.

The Water Footprint of Energy

How much freshwater is required to produce one unit of energy?

Natural gas, coal, crude oil, photovoltaics, wind – every type of energy requires a different amount of water to generate power. But here’s the thing: fossil fuel power plants are super thirsty. For example, according to the Union of Concerned Scientists, “a typical coal plant with a once-through cooling system withdraws between 70 and 180 billion gallons of water per year and consumes 0.36 to 1.1 billion gallons of that water.” To give some perspective, the water withdrawn is enough to fill between 105,991 and 272,549 Olympic-sized swimming pools – every year. And there are thousands of coal plants around the world.

By comparison, wind energy requires virtually no water to operate, and only minimal water for manufacturing and site development. In fact, a new report found that solar photovoltaic systems and wind turbines consume about 0.1 – 14 percent of the water (to generate 1 MWh) that a coal plant would over their respective lifetimes.

Renewable energy offers a double whammy of climate solutions. Reducing our dependence on dirty energy will significantly reduce the greenhouse gases we put into our atmosphere from the power sector. Clean energy technologies also tend to use a tiny fraction of the water dirty energy does – allowing us to better cope with climate impacts we’re already experiencing, like drought. In fact, in 2014, wind energy alone saved drought-stricken California 2.5 billion gallons of water.

The Energy Footprint of Water

How much energy is required to supply one unit of freshwater?

We’re not sure if you’ve noticed lately, but humans need water to survive.  When getting water (or disposing of it) is instant and simple – through a showerhead, faucet, hose, or toilet – it’s easy to forget that it takes a lot of energy to get it to us, as well as to heat, cool, and clean it.

Another way to think about the energy impact of water is as its carbon footprint. Water supply and disposal systems require vast amounts of energy to operate, and most of our energy systems still rely on conventional dirty sources.

In fact, according to River Network, the carbon emissions generated from the energy needed to move, treat, and heat water in the US is about 290 million metric tons a year, or the combined annual greenhouse gas emissions of Alaska, Delaware, Hawaii, Idaho, Maine, Nebraska, Nevada, New Hampshire, Oregon, Rhode Island, and Vermont.

As we continue to move away from dirty fossil fuels, our water systems will become less and less carbon-intense. It’s a no-brainer: using less water and producing less carbon is better for our planet and for people.



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