Electric cars cut solar payback times in half, says British Gas

Electric car drivers could slash the payback time of installing solar panels to under five years, according to British Gas figures released last week.

The Centrica-owned utility has based its analysis on a 2.52kWp system installed at the home of actor and TV presenter Robert Llewellyn, who uses the panels to charge his Nissan LEAF.

Since installing the £11,500 system three months ago, Llewellyn's panels have generated enough energy to power 2,290 miles of the 2,680 miles he has driven during that time – around 85 per cent.

British Gas calculates that it costs £150 to drive 1,000 miles in a petrol car and £37.10 in an electric car, but using Llewellyn's figures for a solar-powered electric car, the same distance costs just £5.38.

If the average driver travels 12,000 miles a year, an electric car owner with a similar-sized solar system to Llewellyn would spend under £65 on a year's motoring, saving £1,736 on petrol costs as well as raking in £1,055 worth of feed-in tariff payments.

These combined annual benefits mean the £11,500 system should pay for itself in around four and a half years, British Gas said, rather than the average 10 years.

"Through solar-generated energy, our customers can significantly cut their fuel costs and help reduce Britain's carbon footprint," Dean Keeling, managing director of British Gas Smart Homes, said in a statement. "Solar-charged vehicles have real potential on our roads, and from the moment the panels are installed customers can begin to reap benefits."

In related news, a report (PDF) released last week revealed the cost of installing solar power in the United States fell by 17 per cent in last year and looks set to drop even further.

Prices fell by an additional 11 per cent during the first six months of 2011, according to research by the Department of Energy (DoE) affiliated Lawrence Berkeley National Laboratory in California.

While PV module prices have fallen steadily since 2008, the Lab found non-module costs, such as installation labour, decreased 18 per cent for residential and commercial PV systems in 2010.

Report co-author and Berkeley Lab scientist Ryan Wiser said: "The drop in non-module costs is especially important as those are the costs that can be most readily influenced by solar policies aimed at accelerating deployment and removing market barriers, as opposed to research and development programs that are also aimed at reducing module costs."

However, shrinking federal, state, and utility incentives in 2010 partially offset the decline in installed costs, the report says. While pre-incentive installed costs fell by $1 per Watt (W) for residential and $1.50/W for commercial PV in 2010, the decline in 'net' (or post-incentive) installed costs fell by $0.40/W for residential PV and by $0.80/W for commercial PV.