Solar powered home in Boulder, CO
One year ago, Engineer Steve Johnson decided to take the plunge and install solar panels on the rooftop of his Boulder,Colorado home. His south-facing asphalt shingle roof (extending over a 4-car garage) had few surrounding trees (minimizing shade on the rooftop) and the house itself was newly built. Perhaps most importantly, the Boulder area is exposed to 157 sunny days and 184 partly sunny days per year.
Johnson was able to use local rebates from his electric utility (Xcel) to cover the cost of the panels, leaving him to foot the installation bill that he was able to write off (up to $2000 of the bill) on his federal tax bill at the end of the year. He chose the system size using NREL’s PVWatts Solar Calculator – eventually settling on a 5.88 kW system, enough to cover 100% of his annual electricity needs (in a gross sense, without considerations like when he needed the electricity versus when it was generated).
His final costs:
Cost of system (pre-rebates and incentives): $43,000
Johnson’s Final Cost (after rebates and incentives): $15,014
In Boulder, Johnson is able to capitalize on friendly net-metering policies that allow him to sell his excess power back to the grid, receiving a credit for each kWh returned to the wires.
In the year since he installed the panels, he has dropped his utility bill by more than $1100 – roughly giving his panels a 15 year payback period (versus 40+ without incentives).
Check out the article that Johnson wrote about his experience here, including a discussion of the downsides of his new solar installation.