Comments on: The Energy-Water Nexus

By: Lou Grinzo

Lou Grinzo — Mon, 10 Aug 2009 11:59:39 +0000

Good article, but I would add that there’s a flip side to the e/w nexus that is too often overlooked: When you build any thermoelectric generating plant (nuclear, coal, nat. gas, oil, etc.), that uses a supply of water for cooling, you’re buying into a decades-long dependency on that source. If the available water is reduced in volume or increased in temperature enough by a heat wave, you could be forced to throttle back or shut down the plant. In recent years there have been numerous instances of this, including this year in France when a portion of their nuclear power plants had to be throttled back, forcing them to import enough electricity from England to power Paris. We’re appropriately concerned about CO2 emissions from power plants, but we need to be equally concerned about their water requirements and dependencies.

By: mitch

mitch — Thu, 28 May 2009 19:06:51 +0000

You state that, “… 800 gallons are required to generate one megawatt-hour of electricity.” Did you really mean kilowatt-hour?

By: planetrelations

planetrelations — Tue, 05 May 2009 00:26:47 +0000

To elaborate on the energy requirements for water, according to the California Energy Commission, it takes 4,000 and 12,700 kWh per million gallons for water that is supplied, treated, consumed, treated again, and disposed of in Northern and
Southern California, respectively. The number is so much higher for Southern California because of the energy requirements to convey water from the north, and also from the Colorado River.

By: Tricia Kuse

Tricia Kuse — Mon, 04 May 2009 15:38:37 +0000

Energy and water can also work together as a solution. Through performance contracting, energy efficiency upgrades generate savings on utility bills that can help fund water efficiency measures such as bathroom fixture upgrades and other water-savings improvements. For example, Charleston, South Carolina installed a smart irrigation system in its parks and around municipal buildings that analyzes daily weather data from satellites and combines it with information about the type of vegetation, soil, ground slope and other factors to provide the exact amount of water to keep the landscaping green and growing when the plants need it, not when they don’t. The system cuts water use by up to 40% and was paid for through savings on utility bills.

By: Noree

Noree — Mon, 04 May 2009 12:16:31 +0000

Excellent post. One thing to remember though – it’s not like water is “destroyed” or “used up” in most of the uses above, especially cooling purposes. It’s not like we’re burning water like coal. Still, we obviously have a challenge on our hands keeping it clean and not contaminating what we’ve got!