Sunday, December 16, 2012

Longmont's Savings from Solar-Energy Panels don't Meet Expectations

Solar panels at Centennial Pool and the Longmont Recreation Center are pulling in half the savings they should be, according to Longmont city staff.
Solar panels, including these at Centennial Pool
in Longmont, haven t yet generated as much savings

When the panels were first hooked up in 2009, they were part of an energy conservation plan that was supposed to save the city $160,855 in the first year, including $32,000 from the solar panels themselves. As it turned out, the city saved $170,067 from 2009 to 2010 -- but only $16,000 of that was due to the panels.

"These are supposed to have a 12-year payback," said Mike Frailey, the city's energy services specialist. "But based on year one, it'd be more than that."

Leaving out grant funding, Longmont paid about $410,000 total for the solar arrays, used to help heat the pool water in both buildings. A typical system, Frailey said, has about a 25-year lifespan.

The 2009-2010 figures are the most recent ones available, though the 2010-2011 figures are nearly complete, according to city staff.

The apparent reasons range from design error to bolt from the blue. Literally, in the latter case.

"The situation at the rec center is totally unique -- the building got struck by lightning," Frailey said. "Not only did things get messed up with the solar system when that happened, there were things that got fried that didn't fail until later."

Other causes were more earthbound. According to Frailey and recreation director Jeff Friesner, a subcontractor's calculation mistake meant the systems produced 30 percent less energy than they should have. The main contractor, McKinstry Construction, is now in talks with city staff about how to fill that gap, by adding more panels or reconfiguring the current ones, for example.

Add to that a leak in the pipes of the rec center's leisure pool -- one that took months to track down and required the pool to be drained three times to find. Every time a pool is refilled, the water has to be reheated, using more energy.

Given all that, the amazing thing may be that the city still netted more savings than expected overall.

Much of the gain came from changes to the lighting used by the city, along with "retro-commissioning" city buildings -- essentially, giving the buildings a tune-up and making sure that all the systems inside are performing to spec.

"Even with the shortfall we had with the solar panel systems, we actually saved more than $9,200 above what was guaranteed," Frailey said.

New equipment such as the solar panels is one reason recreation fees are going up by about 10 percent in 2013. If you're going to add gear, Friesner said, you have to add the money to take care of it.

"We're trying to make sure we have the money available if the pump motor, the glycol or anything else needs preventative maintenance," he said.


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