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St. Louis County office building to become solar panel testing ground

Margaret Hodnik, vice president of Minnesota Power, talks about the solar panel experiment taking place on the roof of the St. Louis County Government Services Building in Duluth during a news conference Wednesday morning, Feb. 19, 2014. (Bob King /

Solar panels from three different manufacturers -- including two made in Minnesota - will battle it out on the roof of a downtown Duluth office building to see which can generate the most electricity in a Northland climate.

Three 10,000-watt solar systems will combine to be the largest photovoltaic system in northern Minnesota, tied into the electric grid and providing a hefty chunk of the electrical needs of the seven-story St. Louis County Government Services Center.

The panels will cost about $170,000 combined. But Minnesota Power is providing the county with about $116,000 in renewable energy rebates, making the cost easily justified, with a payback in just a few years.

Minnesota Power has hired the Natural Resources Research Institute at UMD as an independent auditor to monitor the electrical output of the three systems and to determine the county's precise energy savings.

The solar panels, which convert light to electricity without creating any emissions, and with no moving parts, will come from Mountain Iron-based Silicon Energy, Bloomington-based TenKsolar, and from Trina, a Chinese manufacturer.

"We know that Minnesota has the same solar capacity as Houston, Texas. Even on cloudy days we will get generation out of these units. And we also know they are most efficient when it's cold, so that's not an issue,'' said Tony Mancuso, the county's property management director. "Now we can see which one of these will hold up best to our climate. And which one gives us the most bang for the buck."

For example, Mancuso said, Silicon Energy's units are said to be among the most durable, and best able to shed snow. But they are also more expensive.

Craig Kedrowski, a regional account manager for Minnesota Power, said the system on the office rooftop is exactly the type that will help the Duluth-based utility reach its state-mandated mark of generating 1.5 percent of its electricity from solar power by 2020. Kedrowski said they hope to use the county project as a demonstration for other government agencies, private businesses and homeowners considering a move to solar.

Large, commercial solar energy systems tied into the larger electrical grid -- so-called distributed power generation -- are getting more attention as technological advances make them more feasible, Minnesota Power officials said, and as government mandates for renewable power increase.

"This gives us a good reading of which units will work best up here and what kind of maintenance they'll need,'' Kedrowski said. "And it will be an example of what technology is out there for other people considering going this route."

On a sunny day in the summer, the panels could provide up to one-third of the building's energy needs.

Matt Mlinar, NRRI Research Coordinator, said his crews will look at how snow, low winter sun angles, cloud cover and humidity affect electrical output and how the units stack-up for durability against the region's bitter cold. He said they'll use the results as a "road map" for future solar projects in the region and for residential solar installations.


The solar panels are just a small part of the energy-saving design that's going into the $21 million reconstruction of the 1981-vintage government building, the largest construction project the county has ever done. Other efforts include a recently-installed white rubber roof that reflects sunlight and heat, keeping air conditioning costs down.

Mancuso also demanded triple-pane windows, extra insulation and the highest-efficiency heating-ventilation-air conditioning components available. That includes upgrades such as all-LED lighting and variable flow fans that use far less electricity.

Minnesota Power also will install energy monitors for each floor so both county and utility officials can see in real time how much energy each part of the building is using.

The refurbished building "is going to be 61 percent more efficient than the same-size modern office building with standard construction,'' Mancuso said. "I can't imagine how much more efficient it will be than the old systems we had in there.''

The high-tech energy investments are projected to pay for themselves long before the building needs another makeover, Mancuso said, meaning taxpayers will share in the savings.

"People say this is cutting edge. But it really isn't. They've been doing this stuff in Japan and Europe for years now and we're just catching up,'' Mancuso said.

In recent years the county installed solar panels on the Duluth courthouse parking ramp, for example, which have nearly eliminated an electric bill for the facility. The county also painted the interior white and installed high-efficiency lights. Now, on some months, the parking ramp is generating revenue for the county from Minnesota Power because it's generating more electricity than it uses.

In 2008, the county installed six wind turbine generators on top of the building, each capable of generating 1,000 watts of electricity if the wind is blowing at 20 mph. Those units have worked well, Mancuso said. But he noted that solar is a better investment because there is no maintenance or mechanical problems.

"Having something that works without moving parts is a big plus,'' he said. "And solar is usually peaking at the same time the building's energy demand is at peak, in the middle of the day. It's a good match for us."