According to a Report by
CH2M Hill Jan Dell, Vice President of Engineering, stated, “Not all electricity is water equal.”
Here’s how it breaks down according to the article:
- Coal uses 520 gallons of water to produce one megawatt for an hour.
- Carbon and capture coal needs 990 gallons of water for that same megawatt.
- A photovoltaic solar panel uses 30 gallons of water.
- Power from wind only requires one gallon per megawatt hour.
Most energy companies are not even tracking their water footprint but we expect that to change as climate change, pollution, and population continue to make greater demands on the planet’s 2.5 percent stash of fresh water.
On the west coast we use Natural gas for electricity as well as Hydro-Electric and Nuclear. I'd like to see CH2M Hill detail those that are more relevant for us. Hard to understand how photovoltaic uses any water, especially when it's the closest to the consumer for all energy sources.
Sources:
http://blog.airdye.com/goodforwater/2010/03/02/electricitys-water-footprint/
Electricity’s water footprint
March 2, 2010, 6:00 am by Robin Bertelsen
Maybe it’s just the news we’re watching, but it does seem like carbon footprints, sustainable resourcing, and being eco-friendly are making their way into everyday life. And while, Wal-Mart and Marks & Spencer are making news this week, we’d like to see more attention paid to water footprints. Water is simply not fully accounted for in the same way carbon is.
For example, it takes water to generate energy. Lots of water. After agricultural use, power plants are the second largest water consumer in the country. Of course, not all of it is lost, as in the case of a hydro-power plant where the water continues downstream.
GreenBiz.com reported from last week’s Corporate Water Scarcity Risks and Footprints conference in San Francisco about the widely varying quantities of water needed to produce a kilowatt hour of electricity. Vice President of Engineering at
CH2M Hill, Jan Dell, put it this way, “Not all electricity is water equal.”
Here’s how it breaks down according to the article:
- Coal uses 520 gallons of water to produce one megawatt for an hour.
- Carbon and capture coal needs 990 gallons of water for that same megawatt.
- A photovoltaic solar panel uses 30 gallons of water.
- Power from wind only requires one gallon per megawatt hour.
Most energy companies are not even tracking their water footprint but we expect that to change as climate change, pollution, and population continue to make greater demands on the planet’s 2.5 percent stash of fresh water.
http://www.greenbiz.com/blog/2010/02/26/forgotten-water-footprint?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+greenbiz%2Fresource-efficiency%2Fwater+%28Resource+Efficiency+|+Water+|+GreenBiz.com%29
Exploring the Forgotten Water Footprint
Published February 26, 2010
It is becoming increasingly common for companies to measure and report the water they consume within their four walls. Yet they rarely track all the water used to make the electricity powering their operations.
It's called the forgotten water footprint and it's about to get a lot more attention. The
World Business Council for Sustainable Development (WBCSD) is working on a new module for energy to be added to the
Global Water Tool, the groundbreaking resource introduced in 2007 that helps companies assess water risks in their businesses and supply chains.
"Why are we building this?" Jan Dell, vice president of engineering firm
CH2M Hill, asked during a business conference Thursday. "Because the world has been so focused on counting carbon emissions, we're concerned that in our race to low carbon energy, have we forgotten about water along the way?"
The water intensity of electric power generation varies wildly, Dell explained at the
Corporate Water Scarcity Risks and Footprints conference being held through Friday in San Francisco. CH2M Hill led the development of the Global Water Tool in partnership with the WBCSD.
"Not all electricity," Dell said, "is water equal,"
For example, it takes 520 gallons of water to produce 1 megawatt hour of electricity in a coal-fired power plant. Add carbon capture and storage -- which some hail as a low-carbon solution that's needed so we can continue burning plentiful but dirty coal -- and water use nearly doubles to 990 gallons per megawatt hour of electricity.
On the other end of the spectrum is photovoltaic solar energy, which takes roughly 30 gallons of water to produce one megawatt hour of electricity. The least water intensive energy source is wind, which consumes just 1 gallon of water per megawatt hour.
Obscuring the problem is the fact that carbon and water are not accounted for in the same way. Under the Greenhouse Gas Protocol, companies typically report their so-called Scope 1 and Scope 2 greenhouse gas emissions, which are direct emissions and indirect emissions from the electricity they consume, respectively. Water reporting, in contrast, usually only covers direct use, not what is used in the electricity they buy.
"This is the so-called energy water nexus that needs to be balanced," Dell said.
A survey of more than 100 of the world's largest utilities found 90 percent tracked their greenhouse gas emissions, but just 40 percent reported water use. Meanwhile, 56 percent of the top oil and gas companies reported emissions, but only 40 percent did the same for water.
The potential impact from giving water use short shrift compared to carbon is significant, Dell said, particularly as a variety of factors combine to put more pressure on the world's water sources, such as population growth and climate change.
"This is a problem because the forgotten footprint of water consumed in energy production could lead us astray and have us put in coal carbon capture and storage," Dell said, "driving zero to the hero of carbon but having huge impacts on water use."
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