Despite all of the excitement about the declining cost and increasing performance of photovoltaic solar, the nation’s homeowners have been lackadaisical about putting panels on their roofs. Last year, there were a record 40,000 residential solar installations in the U.S., but that number is a tiny fraction of the 130 million total homes in the country.
A team of engineers from General Electric, the sponsor of this magazine, want to increase the number of homes with solar roofs by halving the cost of a standard 5-kilowatt (KW) installation, which can provide about 85 percent of the average home’s electricity needs.
The project, called the Smart Grid Ready Residential Solar System, partners GE Global Research and its Industrial Solutions businesses with the New York State Energy Research and Development Authority (NYSERDA). The goal is to put 10 easy-to-install, low-cost systems on roofs in Syracuse and Albany by August.
Meanwhile, a similar project in San Diego — which is part of a separate program called the California Solar Initiative – has crews performing energy audits on 10 homes, in addition to the rooftop solar installations. The project is a partnership with San Diego Gas & Electric.
Both projects are the result of the engineers’ detective work into why solar is so expensive to install, said Charles Korman, the chief technologist for solar energy at GE Global Research. It isn’t the manufacturing cost of the technology: “Solar is as cheap as it’s ever been,” he said. Rather, it’s because there are so many different products available for rooftop arrays that every job is effectively a custom installation. And then there are the high labor costs. Most systems require specially trained electrical contractors to connect high-voltage systems.
The need for highly specialized labor and custom installations drives up the installed cost of solar to about $7 per watt nationwide, or roughly $35,000 for a 5 kW installation, before government incentives.
Korman wants to bring the cost down to about $21,600 or between $4 – $4.50 per watt. To achieve this goal, GE would offer a standardized kit that includes modules that output low-voltage alternating current (AC) power instead of the high-voltage direct current (DC) power of most modules. Roofers and electricians can safely install these lower voltage systems on standardized mounts, eliminating the high cost of installation.
“The installations will require just the tools and skills of ordinary roofers and electrical contractors,” he said.
Homeowners who participate in the new program will also receive a GE Nucleus home energy management system that displays how much electricity the array is generating, and how much appliances are using.
If the project is financed with a low-interest home equity loan, the homeowner’s electricity bill savings will more than offset the monthly loan fees, Korman said. “The roofing industry does 7 million rooftop retrofits a year,” he noted. “The key is to get solar panels on as many of those roofs as possible.”
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