By SUSAN LAHEY
Reporter with Silicon Hills News
The relationship between clean, abundant water and clean, abundant energy is a lot more complicated than most people realize, according to Michael Webber of the Webber Energy Group at the University of Texas. Webber gave a presentation called: Thirst for Power, The Global Nexus of Energy and Water at the Austin Forum at the AT&T Executive Education and Conference Center August 6th.
Webber explained that water is used abundantly in conventional energy production such as oil, natural gas, coal and nuclear plants, as well as for shipping coal. And energy is increasingly necessary for delivering clean water to people and businesses that require it.
Webber pointed out that opponents of hydraulic fracturing to extract oil and natural gas use the large consumption of water as an argument against the practice. And each well, he said, uses 2 million to 9 million gallons of water mixed with sand and chemicals. Efforts to reduce the amount of water call for increased chemicals which doesn’t improve fracking’s acceptance. But hydraulic fracturing accounts for 1.25 gallons of water per million BTUs or British Thermal Units of energy whereas irrigation of corn for ethanol–considered a relatively clean power source– consumes greater than 2,500 gallons per million BTUs.
Water consumption for pulverized coal is .50 gallons per Kilowatt Hour of power, slightly higher than natural gas. Nuclear plants, he said, also require significant amounts of water for cooling. Webber’s slides did not address water consumption by wind turbines or solar, both of which, according the Environmental Protection Agency, are negligible. In areas of low rainfall, for example, water may be used to clean the turbines.
Drilling, Webber conceded, creates huge volumes of wastewater which the industry has yet to figure out how to reuse. Some states, including Texas, allow drillers to re-inject the water into aquifers “and hope it goes away.” Otherwise, water is stored in pits which, if not properly lined, can leak into the water source.
The U.S., Webber said, relies on energy sources for water. Water use accounts for more than 12 percent of national energy consumption. Nearly 30 percent is used for steam injection which extracts heavy oil. Another 29 percent is used to heat water. The rest is broken up into small percentages including water treatment, cooling and appliances. However, the scarcity of water is beginning to result in more energy-intensive water use from such sources as desalinization of ocean water and long haul transfer of water.
There are numerous possible solutions, to turn to energy sources that require less water—such as solar and wind—and to come up with water treatment that requires less energy.
- Desalination consumes huge amounts of energy relative to other kinds of water treatment, plus the water must then be pumped from ocean inland. Mangrove trees, however, naturally remove the saline from water, so more natural alternatives like the use of mangrove trees might reduce the power needed to supply clean water.
- Using brackish or reclaimed water for uses such as power plant cooling and oil and gas extraction also would reduce the consumption of fresh water and the need for water treatment.
- Reclaiming water by various means would increase the water supply, he said. This could include smaller, ‘toilet-to-tap’ treatment options, having the oil and gas industry reclaim the water it uses and using flared gases for on-site thermal distillation of water.
- Agriculture and oil companies could create a water exchange.
- Water treatment plants could create biogas.
- Waste heat from power plants could be used for water distillation systems.
Webber heads the Webber Energy Group at UT which works to find solutions related to energy and the environment, bridging the gap between scientists, engineers and policymakers.