Construction of the leading solar thermal energy project in the Midwest, the scale of which is comparable to two-thirds the size of a football field, recently began at the downtown
Saint Paul RiverCentre.
On the convention center's 30,000-square-foot rooftop will soon be 144 commercial-grade solar thermal panels, which run 8 feet by 20 feet individually, according to project materials.
The $2.1 million rooftop array will kick out 1 megawatt of energy and
decrease carbon-dioxide emissions by 900,000 pounds yearly, materials state.
District Energy St. Paul, which operates a biomass-fueled hot water district heating system and a combined heat and power plant and supplies the convention center's energy, will run it.
Solar thermal energy derives from heating water, explains District Energy project manager Nina Axelson. "It's a very efficient and effective way to use energy," which, she adds, outperforms solar electric power.
Additionally, the RiverCentre's system stands out for its "fuel flexibility," Axelson says.
Extra energy will be shared with the rest of the District Energy system, which includes 80 percent of city buildings, through a grid of heating pipes. Even though similar scenarios are common in Europe, she says, "We never found any other systems like this in the U.S."
As a heating company that has a goal to eventually become 100 percent
renewable, Axelson says, "It's a critical part of what we're trying to
do here."
The system will be up and running sometime in January thanks to a $1 million stimulus grant from the
U.S. Department of Energy (DOE), which District Energy matched. It's the first project that will reach completion as part of a broader DOE initiative called "Solar America Cities," which includes 26 cities--Minneapolis among them--that are tackling various solar
energy technologies.
Source: Nina Axelson, project manager, St. Paul District Energy
Writer: Anna Pratt