How much energy in a gallon of water?

How much energy in a gallon of water?

Readers of ei magazine have noticed an error in the sidebar for an article I recently wrote concerning the impact of the energy-water nexus on manufacturers and the electroindustry.  The sidebar cites an article by Michael E. Webber in Scientific American that describes the amount of energy required to deliver ONE MILLION (my emphasis) gallons of clean water.  When I transcribed Dr. Webber’s table for the article in ei, I mistakenly typed  “one gallon” of water, which is off by a factor of 10^6.

John D. Green of Eaton’s Cooper Lighting Business alertly spotted the error and offered the following analysis of the energy costs in water delivery:

“I was reading your article on Energy-Water in the latest ei. I believe there is an error in the insert on page 30. The title of the second column says “Energy required to deliver one gallon of clean water”. For Lake/River water, as one example, it notes 1400 KWh is needed. Even at $0.05 per KWh, this would be $70 per gallon. Since the didn’t make sense, I found the referenced article from Scientific American and found the chart really depicts the electricity needed for one million gallons – a slight difference, putting the cost down to 7 cents per thousand gallons for lake/river at 5 cents per KWh.”

I’d like to extend my deepest apologies to the subscribers of ei – you deserve better – and my deepest thanks to John for setting the record straight.

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