At the 2010 Metropolitan Water District’s recent Water Summit conference, three presenters, whose remarks are summarized below, stated that large amounts of water are used in the production of energy. In turn, large amounts of energy are used to extract, move, and treat water. We who are concerned about efficient water use have been aware of the latter; it is invaluable to learn about the former. To reduce water use, we need to use both energy and water much more efficiently.
“Energy-Water Nexus”
Dr. Mark Bernstein, Managing Director
USC Energy Institute
Demand for energy and water is increasing; but the climate is changing, making water less available in many areas. We are going to need more water to produce the greater amount of energy we will be demanding; we will need more energy to extract, move, and treat greater amounts of water.
Almost 10% of total national energy use is devoted to extracting, moving, and treating water. The amount of energy used to deliver water to residential customers in Southern California is equivalent to approx 1/3 of total average household electricity use. In a typical city, as much as half of the energy used can be associated with water.
To produce energy, we use water for the following:
- Oil and natural gas: drilling, completion, fracturing, refining.
- coal: operations, tailings, drainage, slurry.
- Power plants: Cooling and operations.
- Biofuels: growing, refining, distributing.
Irrigation represents 80.6% of all fresh water consumed in the U.S. Domestic consumption represents the next largest amount of fresh water consumption: 7.1%.
Actual extraction of water contrasts with consumption. Of fresh water extracted in the U.S., the various sectors extract as follows:
- Thermoelectric 39% (the next author says 48%)
- Irrigation 39%
- Public supply 14%
- Industrial 6%
- Livestock 2%
Concentrated solar power uses more water than photovoltaic solar.
Future transportation fuels are very thirsty:
- Unconventional fossil fuels are 2-4 times worse than conventional fossil fuels.
- Natural gas (range is better to 1-2 times worse)
- Electricity (2-3times worse) [Good if produced by wind or solar PV, worse by nuclear]
- Hydrogen (1-500 times worse) [Good if produced by wind, solar PV,worse by nuclear]
- Biofuels (1-1000 times worse)
We will be using more energy in connection with water:
- Because of stricter treatment standards
- Deeper aquifer drilling and pumping
- Desalinization
- Long-haul pipelines and inter-basin transfer
Reducing greenhouse gas emissions by certain technologies – and certainly by substituting biofuels for oil – will require us to use more water. But climate change will most likely reduce the amounts of water available in many parts of the world – e.g., in the American Southwest, where large populations are concentrating. We will need to use more energy to bring water to these arid areas. But producing more energy means using more water, which will be less and less available.
In roughly half of the continental United States, stream flow is very low in comparison with total water consumption. We will not be able to place many water-intensive power plants in this huge area.
We must try to increase the efficiency with which we us energy and water. We must turn to forms of energy that do not require a lot of water to produce.
“Water and Energy: The Critical Nexus”
Rob Renner
Water Research Foundation
The WRF sees a 50% increase in the amount of energy that we will use to extract, move, and treat water over the next 50 years.
In a typical water utility, 60%-80% of the energy consumption goes to pumping and treating water. For water utilities, costs are going to rise because climate change will impair and degrade water sources, regulations will become more demanding, and new contaminants will need to be removed from water.
Thermoelectric power generation consumes 21 gallons of water per kWhr. A typical residential house uses 20 KwHr/day – equating to 400 gallons of water per house per day. CONSUMERS USER MORE WATER TURNING ON THE LIGHTS THAN SHOWERING AND DRINKING!
John F. Kennedy: “Anyone who can solve the problems of water will be worthy of two Nobel prices – one for peace, and one for science.”
“Water and Energy: The Critical Nexus”
Loraine White
California Energy Commission
Groundwater pumping uses more electricity during the summer months than does pumping for the three largest water conveyance systems (SWP, CVP, CRA) combined.
California’s population of 39.1 million people is expected to grow to 54.3 million by 2040. That means a huge growth in demand for water and energy.
The current goal is to reduce water demand by 20% by 2020 (despite population growth). This means using both water and energy more efficiently.
Logo Metropolitan Water District