Dominion has a comprehensive approach to protecting the environment.
Its power stations use a variety of techniques to reduce harmful emissions,
including electrostatic precipitators and systems that reduce nitrogen oxide.
The addition of control equipment at Mt. Storm, Chesapeake
and Chesterfield power stations will help the Commonwealth of Virginia improve
air quality in Northern Virginia, Hampton Roads and the greater Richmond area.
All of the regions have had problems with ground-level ozone, which is produced
when nitrogen oxides react with sunlight during warm summer months. Nitrogen
oxides are a byproduct of fossil fuel combustion and emissions from automobiles
and industrial plants.
Dominion Virginia Power is voluntarily assisting those areas
by reducing nitrogen oxide emissions during the summer months. The installation
of selective catalytic reduction systems will greatly improve air quality
in Richmond and Hampton Roads. Northern Virginia will benefit from the fuel
switching from coal to natural gas at Possum Point Power Station.
Dominion Virginia Power has designed and installed two new
scrubbers and three selective catalytic reduction systems. Mt. Storm’s
three units generate about 1,650 megawatts of electricity, or about enough electricity
to power half a million homes.
The selective catalytic reduction systems installed at Mt.
Storm decrease nitrogen oxide emissions by about 16,500 tons each year. Alstom
Power of France, which has its U.S. office in Knoxville, Tenn., built the system.
Selective catalytic reduction works much like a catalytic
converter on a car. Flue gas containing the nitrogen oxide emissions from the
combustion process is mixed with ammonia. The mixed gases travel through a series
of catalytic layers, which cause the nitrogen oxide to react with the ammonia.
The reaction converts the nitrogen oxide to pure nitrogen, a benign chemical
that makes up 80 percent of the air we breathe, and water vapor. Both elements
are returned to the environment through the station’s stacks.
The two new scrubbers at Mt. Storm remove 95 percent
of the SO2 emissions from Units 1 and 2. Unit 3 already is equipped with a scrubber.
Each scrubber removes up to 50,000 tons of SO2 per year. The scrubbers, completed
in 2002, are part of Dominion Virginia Power’s overall strategy to reduce
SO2 emissions as part of Phase II of the Clean Air Act Amendments of 1990.
Scrubbers operate by spraying a mixture of pulverized
limestone and water into the exhaust gas of the generating units. Inside the
scrubber vessels, calcium in the limestone reacts with the gaseous SO2 to form
calcium sulfate, commonly know as gypsum. Similar systems will be installed
at Chesterfield Power Station. The agreement calls for scrubbers to be operating
on Unit 6 by 2010 and on Unit 5 by 2012. Selective catalytic reduction systems
also will be added much sooner. Chesapeake Energy Center also will receive nitrogen
oxide controls.
