Electricity vs Water
Posted by Max Dunn Fri, 06 Nov 2009 02:03:00 GMT
What is better – to save water or to save electricity? This is a tradeoff that businesses and industry concerned about sustainability often need to make, and it is not an easy one.
However, an article in the November 6th, 2009 edition of The Economist called Current thinking: Cheaper desalination provides this tidbit: “Even the best reverse-osmosis plants require 3.7 kWh of energy to produce 1,000 litres of drinking water.”
Converting to gallons, this means that 70 gallons of water can be produced from salt water with 1 kWh of electricity. So there we have it – a way to compare water savings to electricity savings.
Interesting. But I’m a bit lost. Is that drinking water made from salt water? Because reverse osmosis in the home doesn’t use any electricity – just standard water pressure. Anyway, my water bill costs me $3 per 750 gallons. So, 70 gallons would cost me about $0.30. Since 1 kWh costs me about $0.20 it would be cheaper to make my own (assuming I lived at the ocean) than to buy it from the utility company – that can’t be right, can it?
Thanks for clarification: this does refer to salt water (I changed the post to clarify that point).
Interesting that you could save money by desalinating your own water. Of course, you pay a lot more than farmers do for their water, but Carlsbad just authorized a desalination plant that will produce water at a cost that is only $250/acre foot more than regular water (or $0.05 per 70 gallons).