A MAP TO MORE SUN

Online solar map provides data on 800,000 Colorado buildings
Heath Urie, January 1, 2011 (Boulder Daily Camera)

"Plans to develop a free online service to give large businesses the ability to calculate how much solar energy they could harvest from their rooftops has gone better than expected…The Denver Regional Solar Map, a product of the Denver Regional Council of Governments, or DRCOG, is now live…

"The tool allows anyone to plug in an address and find out the estimated solar potential of that building. The calculator gives an aerial view of a property, the total amount of electricity that a rooftop solar system could produce and the estimated annual savings on traditional electric bills."

The map (click to enlarge)

"While the project was originally intended to include information on only about 2,000 commercial properties, DRCOG was able to expand the study to include estimates for nearly 800,000 residential and commercial properties throughout the Denver metro area -- including the vast majority of single-family homes…

"The solar map was developed through a $180,000 federal grant through the Governor's Energy Office, and utilized aerial photography, laser measurements and property records to figure out the size and solar capacity of individual rooftops…[Originally] intended to account for variables like shadows, trees and other obstructions in calculating true solar potential, officials at DRCOG decided it would be money better spent to broaden the program to include more properties, with a simpler estimate of solar potential based on property size…"

The calculation (click to enlarge)

"A search of some notable rooftops in Boulder found astounding solar potential…The Home Depot…[could] generate more than 6,000 kilowatt hours during summer months. A full-scale system could save about $65,000 a year off the company's utility bill, according to the calculator…Macy's…has almost identical capacity…Boulder's Municipal Building…already has a solar system that's rated at about 10 kilowatts and saves the city about $1,225 annually. But the solar calculator says the building has the capacity for a system 10 times that size, which could save taxpayers more than $13,000 a year…[T]he optimum size of a large system is about 100 kilowatts.

"The online program also offers links to solar rebate centers, as well as the option to fill out a contact card that is sent to local solar installers. The installers then contact the user to offer estimates and on-site inspections…"