DRAKESBORO, KY - The U.S. Department of Energy has
joined forces with the Tennessee Valley Authority and the Electric Power
Research Institute to demonstrate what might be termed a "grassroots"
approach to sequestering carbon dioxide. The new project will use coal
combustion byproducts to enhance the storage of carbon in vegetation and
A surface mine reclamation project at the 2,558-megawatt TVA-owned Paradise
Fossil Plant near Drakesboro, Kentucky, is serving as the demonstration
Researchers plan to use the gypsum byproducts from the plant's flue gas
scrubber to amend the soil and clarified wastewater from the plant to
provide irrigation for vegetation. Both the soil and vegetation can act
as "biological scrubbers" for carbon dioxide, offsetting a portion
of the carbon emissions released when coal is burned in the power plant.
The scrubber byproducts will be applied as a mulch and should help increase
the survival rate of native tree species and promote growth of vegetative
ground cover. The alkaline nature of the scrubber material will also reduce
acid runoff into local streams from the former mine site and provide cover
and habitat for wildlife.
The project is an example of "terrestrial sequestration," one
of several new approaches being studied by the Energy Department to reduce
the buildup of gases in the atmosphere that can cause global warming.
The "whole plant" approach - a way of integrating several pollution
prevention processes - could offer an economically attractive way for
the power industry to meet future environmental goals, including the reduction
of greenhouse gases.
At the Paradise site, new tree growth will increase the rate of carbon
sequestration and provide new resources for the forest products industry.
Properly conditioned, the soil can also serve as a "living membrane"
to capture and retain carbon. The soil at the demonstration site currently
has low carbon levels, but researchers believe that adding combustion
by-products will increase the soil organic matter which, in turn, will
improve nutrient absorption, water retention, resistence to erosion and
over the long-term, the soil's ability to store carbon.
With the enhanced plant growth and improved soil conditions, the 100-acre
demonstration site is expected to sequester between 60 to 80 metric tons
of carbon over a 20-year period.
Managed by the DOE Office of Fossil Energy's National Energy Technology
Laboratory, the project was initiated in October 2000 with the collection
of soil samples and the receipt of water permits. Total project cost is
nearly $1,3 million, including DOE's portion of $729,007.
The NETL Environmental Projects Division, working with TVA and EPRI,
intends to complete the site environmental assessment, conduct greenhouse
studies to determine the best plant species to use, develop recommendations
for byproduct application and design a carbon capture and water emissions
treatment system. TVA will construct the water treatment system.