Water Use & Conservation
We are fully committed to the responsible use and conservation of water resources, which are critical to our operations.
We heat highly purified and pressurized water in our steam-electric generating units to produce the steam that spins turbines to generate electricity. Water is also the most common source of cooling for these units, which use either once-through cooling systems or closed-loop systems to remove excess heat.
In 2012, total water withdrawn from rivers and lakes for use in our non-hydro generating units dropped by about 25 percent from 2011 levels, to 3.2 trillion gallons from 4.3 trillion gallons.
About three-fourths of our facilities withdraw water and return it to the source (once through) at a slightly elevated temperature but with little to no consumption involved. The other 25 percent have closed-cycle cooling and withdraw very little water, compared to facilities using once-through cooling.
Other ways that we use water in our operations include:
- water sluicing processes (transporting coal ash);
- water treatment systems (sediment ponds);
- air pollution control equipment (sulfur dioxide scrubbers); and
- drinking and sanitary purposes at our various facilities.
Closed-loop Cooling Towers
In 2012, Dominion completed construction of a $550 million, twin closed-loop cooling tower system at the company’s Brayton Point station in Massachusetts, the largest fossil-fired station in New England. The towers are now fully operational, and the amount of water withdrawn from Mt. Hope Bay has dropped by more than 90 percent, from about 1 billion gallons per day to about 100 million gallons per day.
Since acquiring Brayton Point in 2005, we have invested more than $1 billion at the station to improve air and water quality. In March 2013, we announced plans to sell the station as part of a broader strategic decision to exit the merchant coal business.
Reuse and Conservation
At two of our fossil-fired stations, one located in Virginia and one in Massachusetts, we have partnered with local wastewater treatment facilities to reuse their treated waste water rather than fresh water to supply the scrubbers we use to control sulfur dioxide emissions at the stations.
In 2012, we recycled about 3.1 billion gallons of municipal wastewater at company power stations, according to internal estimates. That represents a decline of about 15 percent from 2011.
As in other areas of our business, we also are successfully making use of the Six Sigma process improvement methodology in a number of projects to reduce our city water usage, the water used in our power station systems, and the river water used in the clarified water systems at various company facilities.
CDP Water Disclosure
In 2011, 2012 and 2013 we participated in the Carbon Disclosure Project Water Disclosure reporting process to share data and information about Dominion’s overall water use and risk management practices. A copy of our report is available at https://www.cdproject.net/CDPResults/CDP-Water-Disclosure-Global-Report-2012.pdf.
Natural Gas Business
The water used in our gas transmission and distribution businesses is significantly less than the amount of water that we withdraw or use at our electric generating stations.
We use water to pressure test new and existing natural gas pipelines. This water is filtered and tested before it is discharged in accordance with applicable state and federal permits. Of course, we also use water for drinking and sanitary purposes.
At the Cove Point LNG terminal on the Chesapeake Bay, we use extracted groundwater as part of the vaporization process that assists in turning LNG into its gaseous form for shipment to domestic and global markets, pending regulatory approval. (See Public Policy).
We also produce water when operating our gas storage and production wells. The majority of this produced water, known as brine, is collected and injected into permitted underground injection wells (UIC Class II) that are designed and operated for brine disposal. About one-fourth of this produced water is sent to approved off-site disposal facilities for treatment.