Mayor Emily Larson (DFL) and a cluster of Duluth, Minnesota, city officials announced a new $21 million energy initiative – geared to reduce coal consumption by 40 percent – at an April 12 press conference, while standing symbolically in an empty coal bin at the city’s steam plant.
The coal-burning facility, which currently provides heat to 200 buildings in the city’s downtown core, will burn only natural gas for the next seven months, as part of the energy efficiency test, according to coverage by Minnesota Public Radio.
Every year the city of Duluth burns more than 50,000 tons of coal at its downtown steam plant, the Mayor said. But this year, the seven-month pilot project is expected to cut the plant’s carbon emissions by 15 percent, or about 13,000 tons.
Larson outlined aggressive carbon emission goals in her recent State of the City address, including cutting emissions by 15 percent during her first term, the radio station said. “I feel strongly we have a responsibility. We own a stream plant that’s powered on coal.”
The plant, built in 1932, pulls in 90 million gallons of water from nearby Lake Superior every year; burns coal in four boilers to heat that water under high pressure to 300 degrees; and then sends the steam through a network of underground pipes throughout downtown.
Over the past year the city has spent about $500,000 to upgrade two of the boilers to allow them to burn natural gas.
Officials believe the switch will be cost-neutral because of electricity and other cost savings, MPR reported.
“We will test and analyze and learn how the system can perform under natural gas during the spring and summer,” said Ken Smith, CEO of Ever-Green Energy, which runs the steam plant for the city of Duluth.
In the short term, the plant will need to burn coal during the winter’s coldest months, officials said at the press conference. But if the pilot is effective, the hope is to eliminate the use of coal at other times of the year, the radio station reported.
The project is tied to the city’s plan to convert the steam plant to a closed-loop, hot water system.
Currently, after buildings use the steam from the plant, they discharge the hot water left over into the sewer system, which runs back into Lake Superior.
The city wants to change that to a system by which the water is circulated back to the plant – saving it the expense of heating water from Lake Superior, which registers an average temperate of 42 degrees.
Duluth officials are banking on $21 million from the state Legislature to help fund the project, MPR said.
If that funding is approved and the project moves forward, the city plans to use other energy sources to heat the water, including solar and biomass harvested from northeastern Minnesota forests. A permit application to burn biomass currently is pending with the state’s Pollution Control Agency.
The overall objective, said Larson, is to reduce greenhouse gas emissions, but to do it in a way that also could boost the area’s economy.