Google finds most Asheville rooftops OK for solar panels

 

The number of Asheville rooftops that could serve as a source of solar energy – Google puts that number at more than 20,000 based on satellite imagery and other data – could generate 442 megawatts of power, according to data released by Google last month as part of Project Sunroof.
The Duke Energy coal plant in Asheville has a capacity of about 376 megawatts, while the planned natural gas plant slated to replace it in 2020 will generate up to 560 megawatts.
The Google data, a national effort called Project Sunroof, provides both a bird’s eye view of the citywide data and also allows homeowners to check their own addresses, where the tool estimates the hours of usable sunlight per year, square feet available for solar panels and expected cost savings over 20 years.
It estimates that 66 percent of Asheville roofs could be viable for solar panels.
“If their methodology is good, it’s incredible to see this kind of capacity in a city like Asheville,” said Julie Mayfield, co-director of area environmental group MountainTrue.
While the installation of solar panels on every viable roof isn’t pragmatic, the information suggests that 630 roofs have a solar capacity of 50 kilowatts to one megawatt.
One megawatt of solar energy can power 164 homes, according to the Solar Energy Industries Association.
“There are some big roofs out there that could get you a big bang for the buck and that are owned probably by governments or institutions that might have more capacity to install solar rather than [homeowners,]” Mayfield said. “It also shows we have a lot of flat roofs that are easier to work on and could provide a lot of capacity.”
In a paper released in December, one directed to policymakers, the National Renewable Energy Laboratory found that rooftop solar panels could generate up to 40 percent of energy the United States consumes.
It was a number that was surprising, said lead author Pieter Gagnon, an engineering analyst of solar policy and technoeconomics with the agency.
“It was significantly larger than previous numbers that had been floating around,” he said. “The last time there was a good effort on this was in 2008. There’s more buildings now, there’s been technological advancements – you can generate more power from the same sized roof – and with better data we were able to make a more accurate characterization and it turns out our earlier estimates were somewhat conservative. There’s actually more than we thought
source: http://www.citizen-times.com