Minnesota's largest solar power project is now generating electricity atop two parking ramps at the Minneapolis-St. Paul International Airport.
The 3 million-watt system containing 8,705 solar panels went online Tuesday, and is expected to supply 20 percent of the electricity used in Terminal 1 and to cut carbon emissions by nearly 7,000 tons per year, airport officials said.
"It is a big deal for us," said Dennis Probst, executive vice president for the Metropolitan Airports Commission.
The $20 million solar project is the first of two at the airport. The commission recently approved a plan to install a 1.3 million-watt solar array atop a parking ramp at Terminal 2, at a cost of $8.5 million. Construction is expected to begin next year.
Both solar arrays are expected to make money immediately for the airport — with 30-year savings of $10 million on the first project, and about half that on the second, smaller project.

airport officials launched the project in October 2014 with a ceremony that included Gov. Mark Dayton and climate leader Will Steger, the flip of the switch happened at 12:01 a.m. with no fanfare.
Probst said the airport had intended to hold a ceremony in October after construction workers completed the installation. But the project couldn't be turned on because of issues with Xcel Energy over contract details and installation of the electric meter, he added.
But Probst didn't criticize the utility, which has faced complaints from other solar developers over the slow hookups of large solar projects. Xcel awarded the airport project a $2 million grant from its ratepayer-funded renewable development program.
Minnesota is on the verge of a wave of solar development, including utility-scale projects, shared-solar and rooftop projects. Holly Lahd, electricity markets director for St. Paul-based nonprofit Fresh Energy, estimates that by the end of 2016 that 400 megawatts to 500 megawatts of solar will be built in Minnesota, the equivalent of a large conventional power plant. A megawatt is 1 million watts.
"For organizations that have a lot of land and great solar access, it's becoming a no-brainer to do these projects," Lahd said. "I think we're going to see more of these types of projects, not only at airports but large commercial buildings and smaller sites across the state."
The airport's first solar project is atop the Red and Blue ramps in front of the main Lindbergh terminal, also called Terminal 1. Half of the solar panels were purchased from TenKSolar, whose Bloomington headquarters and manufacturing plant is 10 miles away.
As part of the project, the airport also installed light-emitting diode (LED) lights in four Terminal 1 parking ramps, and intends to do the same at two Terminal 2 ramps. Four electric vehicle chargers also were added in the Terminal 1 project. The total project cost including LEDs was $25 million.
The airport's solar project is 50 percent larger than the state's previous solar leader, a 2-megawatt system in Slayton, Minn., that went on line in 2013. It probably won't hold that mantle for long. Xcel has signed deals with energy developers to build

three massive solar arrays next year. The largest is a 100 million watt project planned in North Branch, Minn., costing $180 million.
Unlike most large solar deals, the airport's doesn't rely on the 30 percent federal solar investment tax credit. Instead, the airport financed the project largely with a federal lending program that buys down the interest rate on bonds. The airport also used $200,000 of public funds, plus the $2 million Xcel grant.
One result is that the airports commission will pay less than 1 percent interest on the bonds. The airport also will own the solar project from the beginning. In solar deals using tax credits, a private company usually would own the project, at least initially, to capture tax benefits that don't apply to untaxed public bodies like the commission.
Probst said that Ameresco Inc., a Framingham, Mass.-based company that planned, built and will operate the solar array under contract, suggested using federal Clean Renewable Energy Bonds or Qualified Energy Conservation Bonds to finance both airport projects, including LED lighting.
"In the end it turned out to be financially much better for the airport," he said.
Lahd said governments, schools and nonprofits seeking to install solar are looking for financing models that don't require complex tax-equity investment structures. The investment tax credit also is set to drop from 30 percent to 10 percent after 2016, making it less lucrative.
"As the investment tax credit declines, you are going to see new financing tools like the Clean Renewable Energy Bonds come into play," Lahd said.
In the airport project, workers built a galvanized steel structure to elevate the solar panels above the top floor's parked vehicles. That represented about 40 percent of the cost of the solar array, Probst said. The same approach will be used at the Terminal 2 solar array.
Although the airport has other flat rooftops, officials have no immediate plans to add more solar. The second Terminal 2 ramp is designed to be expanded with additional floors and a solar project would be in the way. Two older ramps at Terminal 1 are not ideal because they potentially will need reconstruction and might need structural changes to mount solar panels.
The airport is considering subscribing to off-site shared solar projects known as community solar gardens, and has a request for proposals pending. And Probst said part of the Terminal 1's roof could be fitted with solar after it is reconstructed in the future.

David Shaffer • 612-673-7090 • @ShafferStrib