Can Solar And Wind Power Save Our Rivers?

In an era of stressed watersheds and aquatic ecosystems rendered fragile by global warming, we’re learning more about our hidden water use. For instance: 42 gallons – that’s the water footprint for the average kilowatt-hour of U.S. electricity as of 2009.

OK, it’s nothing compared to how much water it takes to produce a big, juicy hamburger – that’s at least 4,000 gallons [PDF] – but then again, you consume a lot more kilowatt-hours of electricity in a day than you do hamburgers. Presumably.

river network, burning rivers

image via Shutterstock

In fact, the average U.S. home uses around 1,000 kWh of energy every month, which means – according to a report from the Portland, Ore.-based River Network – it takes an average of 39,829 gallons of water to meet our monthly energy use, five times more than our direct residential use of water.

The staggering water requirements of our current grid electricity are just one more reason to embrace water-sparing renewables, the group argues in “Burning Our Rivers: The Water Footprint of Electricity” [PDF].

“Expanding the deployment of wind energy and photovoltaic (PV) solar power could vastly reduce wateruse conflicts in some regions,” they write.

Some might argue that not all or even most of the water used to make power from traditional sources like coal, nuclear and natural gas is used up in the process of creating the energy. But that ignores one of the great sins of power production, River Network says: once-through cooling.

The water that is used to cool down conventional power plants might largely be returned to its source, but not without repercussions. “Some of this water is evaporated while the majority of this water is warmed up – causing thermal pollution – killing aquatic life, increasing toxic algae blooms and decreasing the sustainability of our water supplies.”

Furthermore, the biggest source of electricity in the U.S., coal, takes this impact a step further because “immense amounts of water are used or polluted to mine, wash and transport coal before it even reaches the power plant, while even more water is used to consumed at the power plant.”

River Network has a lot of recommendations for fixing the problem, including deploying better cooling technologies. But it’s the endorsement of wind and PV that lead its long list.

“Wind and PV solar require virtually no water to generate electricity, and their lifecycle water footprints are far smaller than hydro, nuclear or fossil fuels,” the report states. “The technology exists for wind to provide 20 percent of our electricity by 2024.”

river network, burning rivers

image via Shutterstock

It does take some water to make wind turbines and solar panels, but not much. Weighted by production, River Network puts hydroelectric’s contribution to the total water footprint of electricity at 29,920 gallons; coal’s at 7,143 gallons per megawatt-hour; natural gas at 1,512 gallons/MWh; and nuclear at 2,995 gallons/MWh. PV, meanwhile, comes in at 2 gallons/MWh, and wind at just 1.

“Since the majority of the water used by wind and PV solar is ‘upstream’ (to acquire and process materials for fabrication), manufacturing can be focused in water rich regions without increasing water impacts in dry regions,” the River Network report says.

5 Comments

  • Reply July 11, 2012

    Geneccs

    your facts do not add up – if it takes 42 gal for 1000 W and coal the worst offender requires only 7 gallons… where is the rest of the 42 gallons?  hydro takes virtually none, nuclear is a lot but not that much – just does not add up.

    • Reply July 11, 2012

      Pete

      Geneccs — I think that the paragraph where you saw that coal figure was incomplete (by not including hydropower) and poorly worded. I’ve revised it to better reflect the data in the report (Table 2 on page 11). Let me know if this makes sense to you.
      Thanks,
      Pete Danko

  • Reply July 13, 2012

    Arthur D. Hall

    How about letting river power  save the rivers.
    Rafts and piers of floating padel wheels and
    under water current generators, generating megawatts
    is perfectly concievable.
    If you know why not, please explain!

    • Reply July 14, 2012

      Pete

      Indeed! We’ve covered many such efforts. See these topics and stories:

      http://www.earthtechling.com/tag/hydrovolts/ 

      http://www.earthtechling.com/tag/yukon-river-kydrokinetic-turbine-project/ 

      http://www.earthtechling.com/2011/08/hydrokinetic-turbine-runs-on-the-mississippi/

      http://www.earthtechling.com/2010/09/marine-hydrokinetic-tech-gets-funding/

      Pete Danko

  • Reply July 16, 2012

    Onahunt

    Pollution free and waste free clean energy wind turbines! Can nuclear, oil or coal say the same?

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