Apr
13
2011

Some solar thermal power for downtown St. Paul

The new solar thermal array: And, yes, this was the largest photo I could find on short notice.
The new solar thermal array: And, yes, this was the largest photo I could find on short notice.Courtesy US Department of Energy
A couple of months ago, I noticed something happening on the roof of the RiverCentre, the big building across the street from the Science Museum. After noticing, however, I didn’t give it any more thought. This was for two reasons: because a couple of months ago it was approximately one billion degrees below zero here, and I didn’t want to stand outside looking at roofs any longer than I had to; and because I’m a firm believer that you shouldn’t stare too long at anything you aren’t certain about. Don’t believe me? Examples: the sun (it’ll burn your eyes), chimpanzees (they will literally tear you to pieces), and roadkill (it’s gross).

At any rate, it turned out that the goings-on on the RiverCentre roof would have been largely harmless to watch, and that they were a part of a big, interesting project that I hadn’t heard about—they were installing a large array of solar thermal panels.

Solar thermal panels, just as a reminder, aren’t exactly like the photovoltaic solar panels you might be thinking of. Unlike panels that use sunlight to produce electricity, solar thermal panels absorb the heat in sunlight (or solar radiation, if the distinction bugs you), and uses it to heat water.

So … the new solar array on the RiverCentre is a joint project between the RiverCentre itself, and St. Paul District Energy, another neighbor of the Science Museum, which supplies hot and cold water to buildings downtown for efficient heating and cooling. The array has 144 solar panels, altogether taking up about the area of half a football field, and they should be able to produce about 1 megawatt of power.

Now, compared to a 1,000-megawatt coal or nuclear power station, 1 measly megawatt probably doesn’t seem like much, but it’s nothing to sneeze at. A single megawatt is still approximately enough to power 1,000 homes. Sort of.

It depends on the average consumption of the homes in the area, which varies from region to region, but 1 megawatt is usually touted as the power consumed by 1000 homes. And, in any case, this is a little different, because it’s not feeding an electrical power grid, but a grid of heat energy for downtown—any extra heat that’s not used by the RiverCentre facilities will be fed back to District Energy, which will redistribute it around the city.

The new array is the largest of its kind in the Midwest, and, in addition to creating a local energy source (as opposed to buy coal or natural gas from somewhere else), it should reduce St. Paul’s carbon dioxide emissions by about 900,000 pounds annually—more or less the amount created by 90 vehicles in a year.

Again, 90 cars’ worth of CO2 may not seem like much, but it’s a start, and it’s kind of cool that that’s just from the panels on one building. And, with the help of a million and a half dollar stimulus from the Minnesota Office of Energy Security, a mix of solar thermal and photovoltaic solar panels are going to be installed on 10 more buildings along the Central Corridor. In addition to the new light rail line from St. Paul to Minneapolis, the Central Corridor is meant to be a showcase for a bunch of energy innovation projects. (Click that last link for a list of projects—there are a whole bunch.)

Pretty slick. (More info and links here.)

Your Comments, Thoughts, Questions, Ideas

curious's picture
curious says:

dude! izzy's ice cream cafe in st. paul is also in on this with its own set of solar panels that produces 30%(at peak times) of its energy! that's totally awsomely COOL, like ice cream(although i prefer my ice cream super cold)!

posted on Wed, 04/13/2011 - 8:05pm
KelsiDayle's picture
KelsiDayle says:

Hey! I'll bet this ties in with the RiverCentre and Xcel Energy Center's award-winning Leadership in Sustainability program.

The second phase of the project

"aims to reduce the carbon footprint of the facilities by 80 percent and make them 20 percent more efficient than average within three years time."

posted on Thu, 04/14/2011 - 12:56pm
Anonymous's picture
Anonymous says:

this is dumb. what a waste of money.

posted on Wed, 04/20/2011 - 8:56pm
JGordon's picture
JGordon says:

Excellent point.

posted on Mon, 05/09/2011 - 10:38am

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