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.
About half of our steam electric 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 half of our facilities use 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
- cooling associated with other facility processes
- air pollution control equipment (sulfur dioxide scrubbers)
- drinking and sanitary purposes at our various facilities
Water-Saving Cooling Systems
Dominion has installed water-saving cooling technology at some of our generating stations.
For example, the Virginia City Hybrid Energy Center in southwestern Virginia uses an air-cooled condenser to remove heat from the system. Fans remove much of the excess heat, resulting in about 90 percent lower overall water use when compared to traditional coal-fired power stations. A similar cooling system was installed at the Warren County Power Station, which became operational in late 2014.
In addition, we are building a 1,300-megawatt natural gas-powered station in Brunswick County, Va., that is expected to begin commercial operation in late 2016. The station will be equipped with an air-cooled condenser to reduce water consumption compared to once-through cooling systems or traditional cooling towers.
Natural Gas Business
The water used in our gas pipeline 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 collected and disposed of offsite or is filtered and tested before it is discharged in accordance with applicable state and federal permits.
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.
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 25 percent of this produced water is sent to approved off-site disposal facilities for treatment.
CDP Water Disclosure
Beginning in 2011, we have participated annually in the CDP “Water Disclosure” reporting process to share data and information about Dominion’s overall water use and risk management practices.
“We are constantly looking for ways to reduce our water footprint at existing and new facilities. For example, at one of our power stations in Southwest Virginia, we installed air-cooled condensers instead of cooling water towers. This reduced the water consumption at the facility by about 10 million gallons per day.“