Innovation And Technology
By investing in science and technology, TVA develops the knowledge and tools needed to protect, conserve, and repair the natural resource base that sustains life in the Tennessee Valley. Researching and utilizing new technologies also helps TVA improve its operating efficiency by providing new ways to obtain more kilowatt-hours from the same amount of fuel input.
Using TVA’s operating facilities as a living laboratory, scientists at TVA’s Public Power Institute apply innovative solutions to actual problems in real-life settings. Through its commitment of time, talent, and funding for technological advancements and innovations, TVA is able to continuously improve its performance, both in delivering affordable, reliable power and in protecting the Valley’s natural resources.
For example, TVA is participating with the Department of Energy, the Electric Power Research Institute (EPRI), and EPA in several demonstration projects to determine the effectiveness of technologies to reduce emissions of mercury into the air. Currently, TVA’s 11 fossil-fuel plants are estimated to emit 3.2 metric tons (3,500 pounds) of mercury each year.
Early evidence indicates that selective catalytic reduction systems used in combination with scrubbers may convert elemental mercury into a form that can be removed using existing downstream emissions-control equipment. At Paradise Fossil Plant, testing over the past three years has shown that mercury is being converted and removed at a rate of 90 percent when the SCR is operating. This approach would result in significant cost savings by eliminating the need to install additional end-of-pipe, mercury-specific removal technology (which has yet to be developed) to extract the mercury from the combustion gases. TVA researchers are looking at a range of technologies to find the most cost-effective and environmentally sensitive solution for all of TVA’s coal-fired power plants.
Mercury measurement data collected at Paradise compare TVA’s new patented mercury analyzer technology with the industry’s current technique for measuring mercury in gases from fossil plant stacks. Preliminary results indicate that the TVA technology provides an immediate, accurate measurement of mercury compared with the current technique, which requires waiting several weeks for lab results. In addition, the TVA approach takes fewer staff to operate, making it more cost-effective. This technology will increase understanding of the chemistry of mercury in a power plant and will help TVA make timely operating decisions to reduce mercury emissions and minimize costs of meeting future mercury emission regulations.
In another innovative project under way at Paradise Fossil Plant, TVA’s Public Power Institute was awarded a contract by DOE’s National Energy Technology Laboratory in August 2000 to develop new ways of helping electric power producers capture, or sequester, carbon dioxide. The $1.3 million Carbon Capture and Water Emissions Treatment System project, or CCWESTRS (pronounced sequesters), evaluates the use of ammoniated wastewater from power plants to irrigate trees, which sequester CO2 and store it in forms that prevent its reentry into the atmosphere.
CCWESTRS examines carbon sequestration on poorly reclaimed surface-coal-mining land on the Paradise plant site. TVA designed and installed a system to drip wastewater from the flue gas desulfurization system, or scrubber, over the entire site. The project also included spreading approximately 30,600 cubic meters (40,000 cubic yards) of scrubber sludge, a nontoxic solid-waste by-product from the plant, over the site and planting 63,000 sycamore and sweet-gum seedlings. The irrigation system started operating in 2003. TVA estimates that 1.5 to 2 metric tons (1.7 to 2.2 tons) of CO2 per year will be sequestered by the trees at the site over the next 20 years. In addition to providing an economically competitive and environmentally safe option to offset greenhouse gas emissions, the CCWESTRS technology helps the environment by developing wildlife habitat and green space.
In Muscle Shoals, Alabama, TVA is demonstrating another technology that prevents harmful industrial pollutants from contaminating the environment. Unlike traditional cleanup methods such as scrubbing, stripping, and absorption, which merely reduce the impact of certain pollutants, TVA’s patented Hybrid Bioreactor converts toxic pollutants to nontoxic products.
The 8.5-cubic-meter (300-cubic-foot) mobile Hybrid Bioreactor uses a process in which naturally occurring microbes are harnessed to destroy toxic chemicals in the water and air. This toxics disappearing act is accomplished in a single step without releasing any harmful compounds. Contaminated waste streams pass through packing material that contains microorganisms which degrade or mineralize the pollutants into harmless compounds such as water and small amounts of carbon dioxide. In most cases, the Bioreactor provides a cost-saving, environmentally friendly alternative to traditional pollution control or remediation approaches. The technology can be used in a variety of applications ranging from site restoration to industrial compliance.
For TVA, focusing on the future means more than technological research and development. It also means helping develop, support, and challenge the nation’s future scientists, engineers, and researchers. As part of this commitment, TVA partnered with DOE, the National Renewable Energy Laboratory, BP Solar, and Home Depot in 2002 to sponsor the first-ever Solar Decathlon. The event brought teams from universities around the country to the National Mall in Washington, D.C., to design and build energy- efficient solar-powered homes.
Like its athletic namesake, the Solar Decathlon consisted of 10 events with different themes that ranged from design and livability to energy balance and interior comfort. The solar decathletes had to supply all the energy for an entire household, including a home-based business. Only the solar energy available within the perimeter of each house could be used to generate the power to compete in all 10 events. Throughout 2004, TVA will provide technical assistance to students preparing for the second Solar Decathlon, which is scheduled for 2005.
One innovative TVA project that will not continue as planned is the Regenesys plant in Columbus, Mississippi. The plant was scheduled to be the nation’s first commercial-sized Regenesys energy storage facility, a large-scale, battery-like power storage plant that could store electricity during off-peak periods and retrieve it for use when the need for power increases. In 2003, the RWE Group, which had recently acquired Regenesys Technologies Limited, canceled further development of the flow-cell technology to be used at the plant. This forced TVA to suspend plant construction in May 2003. Since much of the facility has already been completed, TVA will evaluate the site to determine if other technologies can be installed or if other uses for the facility can be found to serve the area.
The Regenesys technology may yet prove viable. Although the project encountered a number of engineering difficulties during its scaling up to a commercial-sized plant, it’s possible that these problems can be adequately addressed with sufficient time and investment of resources.