Along the river in St. Paul, Xcel Energy’s old coal-burning plant has been replaced by a state-of-the-art natural gas-burning plant. At the new Xcel Energy High Bridge Generating Plant, natural gas powers two combustion turbines that are very similar to large jet engines. The hot exhaust from the turbines is used to make steam to run electricity-generating turbines. The new plant is capable of producing as much as 600 megawatts of power, and allows Xcel to add power to the grid on an on-demand basis.
The industrial history of the site goes back to 1918 when the St. Paul Gas Light Company built the Levee Station gas holder and filtering facility there. Northern States Power Company (now an Xcel Energy Company) purchased the St. Paul Gas Light Company in the 1920s, but the facility continued to provide gas to St. Paul into the 1950s. With the conversion of the gas system to natural gas in that decade, the gas holder and filtering facility was demolished. The site was converted to coal storage for the adjacent High Bridge Generating Plant.
In developing the new facility, Minnesota Pollution Control Agency Voluntary Investigation and Cleanup Program staff John Betcher and Ed Olson worked with Xcel and other partners to remove the contaminants from almost 90 years of energy production on the site. In 2005, buried structures and contaminated soil and debris were removed and approximately 30,000 tons of coal was transported to a landfill. About 3,660 tons of cyanide-contaminated soil was excavated and 13,000 cubic yards of clean fill dirt was brought onto the site.
Xcel built the new High Bridge Plant as part of its response to legislative efforts in 2001 that encouraged utilities to reduce air emissions while increasing electricity production. The new plant can generate more than twice the power of the old coal plant and produces significantly less air pollution—particulates were reduced by 91.5%, sulfur dioxide by 99.7%, and mercury by 100%.
Find out more about the cleanup of the High Bridge site.