Declining solar equipment costs and a one-year extension of the Section 1603 Treasury program, which allows businesses to receive a cash grant in lieu of the 30% federal Investment Tax Credit for installing solar photovoltaic (PV) systems or other renewable energy equipment, have helped boost cumulative grid-connected solar electric installations in the United States to more than 2.85 GW, according to the Solar Energy Industries Association (SEIA). Western Maryland Distributing, a Cumberland, Md.-based wholesaler of alcoholic beverages, recently took advantage of these incentives by installing a 91,080W solar array on its rooftop, which is projected to produce approximately 118,621kWh of electricity per year.

“The owner initially approached us to find viable ways to lower his electric consumption for the business,” says Betsy Delozier, a former lineman and owner of Big D Electric, an electrical contractor also located in Cumberland. “First, we installed an energy controller on his main distribution panel to help bring all motor loads to optimum efficiency. Next, we retrofitted the luminaires from high-bay metal-halide to T5 fluorescents with motion detectors. These two measures cut the building’s electric consumption by about 30%.”

But the distributor and contractor didn’t stop there.

“Once we lowered the bill to a place we felt was manageable, we discussed the aspects of a solar array to offset all the other loads,” she says. “The rest is history.”

Comprised of 396 230W modules on a 20° tilt racking system, the PV system was designed to attach to the standing seam roof with no penetrations. Big D Electric also installed 12 8,000W inverters tied into four panels fed from a main 600A panel.

“We did not use any combiner boxes on the roof,” explains Delozier. “Instead, we brought each wire from the arrays into the inverters where we dead ended-them. The electric utility required an external disconnect near the metering equipment, so we supplied one that can disconnect the AC side of the inverters at any time.”

According to Delozier, all the racking was built on the ground and lifted in 20-ft sections to the roof via a telescoping forklift. From there, each rack section was carried and positioned into place, keeping 10 ft of distance between rows for shading purposes. Panels were also brought up using the forklift and carried one at a time to each location. Although the installation took just 15 days, it was spread out over an eight-week period and involved several challenges.

“Weather was definitely the biggest hardship,” notes Delozier. “Many days, the temperatures were below zero. One day it had even snowed, but our employees still got up on the roof with a push broom in hand, sweeping off the snow to create a safe passage.”

Finished in time to be fully operational by Dec. 31, 2010 — so that the owner could take full benefit of the Federal Tax credit for the year — the solar array will offset the building’s electric bill by at least 90%. Furthermore, the owner is taking advantage of the solar array by opening Western Maryland Distributing’s doors to the community to demonstrate the benefits of going green.

“Although the system cost $405,000, the building owner received a federal tax credit of $121,755 in addition to a mid-size solar grant from the state of Maryland for $45,540 and a state tax credit of $5,040,” says Delozier. “It is also earning 91 Renewable Energy Credits (RECs) a year for the next 15 years, which accumulates to $47,000 in the first two years of operation and then diminishes by $50 per REC until they are exhausted in year 15 of the system.”

Overall, the payback period will be less than seven years.