The Minneapolis-St. Paul International Airport is planning the largest solar power installation in Minnesota to date.

The $25.4 million project, announced Thursday at an airport news conference that included Gov. Mark Dayton and explorer and climate activist Will Steger, is expected to generate nearly 20 percent of the airport’s electricity after its completion in the fall of 2015.

The 3-megawatt solar installation will be built on two parking ramps in front of the main terminal. The solar panels will be mounted above the top parking level of the ramps so as not to take up any of the parking spots.

The Metropolitan Airports Commission hired Minneapolis-based GreenMark in March 2012 to explore energy projects for the airport. GreenMark is an environmental marketing agency that specializes in putting together sponsors to develop clean energy and environmental projects at major venues. GreenMark was behind the innovative rainwater recycling/clean-water partnership with Pentair and the Minnesota Twins at Target Field.

Mark Andrew, founder of GreenMark, kicked off the Thursday news conference by saying, “This is the beginning of scaled solar power in the state.”

It’s a signature project that highlights Dayton’s clean energy initiatives, including a new solar energy standard enacted by the Legislature last year requiring investor-owned utilities to produce 1.5 percent of their electricity from solar by 2020. The requirement is expected to accelerate investment in solar projects throughout the state.

“This project will create 250 new jobs, and make our airport one of the most energy efficient in the world,” Dayton said.

The airport array will be 50 percent larger than the state’s current solar leader, a 2-megawatt system in Slayton, Minn., that went on line in 2013 to serve customers of Minneapolis-based Xcel Energy Inc. Just south of the airport, retailer Ikea built a large rooftop solar project in 2012 that was the state’s first 1-megawatt array. One megawatt is 1 million watts.

Jeff Hamiel, executive director and CEO of the airports commission, said that careful calculations were done on the sun patterns at the site, the angle of the installed solar panels and flight paths to ensure the installation won’t distract pilots.

“There will be no reflection that will cause a problem for the flight crews flying in or out of Minneapolis-St. Paul Airport,” Hamiel said.

Ameresco Inc., a renewable energy company based in Framingham, Mass., will lead the project’s installation. As part of the project, Ameresco will convert 7,700 light fixtures in all four parking ramps to more energy efficient LED technology and add four additional electric vehicle charging stations in the ramps.

Hamiel said the project will result in $10 million of cumulative economic benefits for the airport over 30 years.

The project is being financed partly with a $2 million grant from Xcel’s Renewable Development Fund, which is funded by the utility’s Minnesota ratepayers. MAC officials said another $23 million is being raised by selling qualified energy conservation bonds, which feature a built-in federal tax credit for investors. The federal government allows state, local and tribal governments to issue the bonds to finance some types of energy projects, including solar.

Also on Thursday, the Minnesota departments of Employment and Economic Development, Commerce, and Agriculture, and the Environmental Quality Board, released a new analysis of the state’s clean-energy economy. It said that Minnesota’s clean-energy efforts including wind, solar and biomass are helping the state reduce its dependence on imported, nonrenewable energy sources.

According to the report, only 4 percent of electricity generated in Minnesota in 2000 was from renewable energy, but by 2011 renewable power contributed 16 percent of total generation. Employment in the clean energy sector grew 78 percent between January 2000 and the first quarter of 2014 to a total of 15,300 jobs.