Wednesday, October 31, 2012

Old Town Parking Deck's Solar Power Generation Doing Better Than Expected

Bright sunshine isn't just helping the city's tourism sector — it's also powering a multi-million dollar public facility.

Solar power generation at the city's 2-year-old parking deck in Old Town is meeting and sometimes exceeding expectations, city officials and project contractors said.

Data from the city's Downtown Development Authority show the solar panel array on the roof of the public garage along Eighth Street generated one third of the deck's total electricity use in July.

"It's just been a phenomenal year, and I'm real pleased with how it's going," said Matt Vajda, owner of Voltage Electric Inc. of Traverse City that installed the 40-kilowatt system on the roof of the $7.9 million structure.

The city spent about $240,000 to install the solar power system, which has an estimated 20-year payback. The system produces little electricity in the winter months when the deck uses the most power. For example, the deck used more than 47,000 kilowatt hours of electricity in January, when the solar panels generated just over 3 percent of its power use.

But the deck's solar generation powered up thanks to a warm, early spring. The panels produced more than 4,300 kilowatt hours in March, more than 18 percent of the deck's total power use. April was even better, as the deck generated nearly 26 percent of its electricity from solar power.

Vajda said April's results were about 40 percent over projections, and May's solar generation was 22 percent higher than expected. April was a sunny, cool month, and Vajda said solar systems are most efficient in clear and cold conditions.

"You have more inefficiencies when it's warm," Vajda said.

The solar power system is among the features that helped the city gain a LEED certification for the deck from the U.S. Green Building Council, which stands for Leadership in Energy and Environmental Design.

But city officials said it's more than just an environmental measure, as electricity costs are among the deck's highest operational expenses.

"There's a good amount of electric demand, even though it's not an occupied building," said Rob Bacigalupi, deputy director of the city's Downtown Development Authority.

It includes lighting, an elevator, electric heat, powering a small business office and operating the deck's snow-melt system. Those costs are highest in the winter months when the solar power system is generating at its low point. But officials said during a typical summer, when operating costs are lower, the deck should get about a third of its energy from solar panels.

"It's right on track," Bacigalupi said.

The DDA recently took steps to bolster energy efficiency at the city's Larry C. Hardy Parking Deck along East Front Street by installing more efficient LED lights throughout the structure. The $118,682 lighting project is expected to save the city more than $21,000 a year in energy costs, Bacigalupi said.


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