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UPDATED: Engineer urges Kingsport BOE to pursue solar power

Rick Wagner • Jul 19, 2017 at 3:30 PM

Note: This article has been edited to clarify the power generation of the residential solar system over the most recent bill and the projected payback and life of the solar system. 

KINGSPORT — Retired Eastman Chemical Co. engineer David Hrivnak, who powers his home and two vehicles with solar-generated electricity, on Tuesday strongly encouraged city school leaders to proceed with a solar project but also recommended they ask lots of questions.

In his presentation, he also outlined LED light energy savings at his church, Holy Trinity Lutheran. 

A sales representative for international energy company Ameresco proposed at the July 6 Board of Education meeting that Kingsport City Schools, and possibly the rest of city government, plug into solar power. It is proposing that the BOE aprove a contract for a free “30 percent” evaluation to determine the options and feasibility of a combined program of solar panels and conversion to energy-saving LED lights. Such a contract might go before the board for a vote after review by City Attorney Mike Billingsley and Ameresco officials.

The company proposes savings with no up-front costs to the school system by using grants and low-interest loans, while Hrivnak’s home system takes advantage of federal income tax credits. He urged the board to check “the fine print” and be sure installation, ownership, maintenance costs and monitoring are addressed. For instance, he said, rooftop panels should be installed only on new or nearly new roofs because of the expense of removing them for roof replacement. He also suggested replacing any inefficient or marginally operational cooling systems to lower power needs.

He also said he is a firm believer in LED lighting since its price has fallen and it lasts much longer than incandescent lighting. Converting 75 percent of the Lutheran church fixtures to LEDs has saved about $2,800 a year, he said.

“Today, a good part of the day, the meter went backwards,” Hrivnak said of his home American Electric Power meter, meaning the solar array on his roof produced more power than the house used. However, he said, that extra power is “banked” with AEP over a one-year period, but after that, any power generated over his usage level is lost to him. He said that’s why Ameresco officials are correct in saying the school system should size its solar system to provide roughly the amount of power it uses.

“It is always cheaper to save energy than put extra solar panels on,” Hrivnak said. He showed the board his most recent home power bill for $13.06, the minimum connection charge plus Kingsport’s franchise fee. On prime solar days like much of this week so far, Hrivnak said, his panels make the most power and cover his usage on winter and/or cloudy days with lower output. “I get to use them (AEP) as a very large battery,” he said. Last month, his panels produced about 1,200 Kilowatter hours of electricity, or 335 kilowatt hours more than used. Over the most recent 12-month period he produced about 150 extra kilowatt hours that were “lost” at the end of his 12-month contract period.

Hrivnak estimated his home system cost him $19,000 out of pocket, but said that without federal income tax credits it would have cost about $28,000. Aside from the household electricity, the system also provides enough power for two electric vehicles to travel about 1,000 miles a month. He estimated a 6 percent return on investment and a 14-year payback on his system he expects to last 30 years, but said the larger scale of a school solar system and grants would make it less expensive per panel and per kilowatt hour. His payback will be better if power rates go up and considering electric vehicle mileage, he said.

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