Thousands of people have spent vast sums of money installing eco-friendly solar panels but most will have probably had them fitted facing the wrong way, according to energy experts.
The solar power industry is being urged to reconsider its approach to installing panels after one of the UK’s leading experts, Professor Ralph Gottshalg of Loughborough University says too many solar panels are facing in the wrong direction.
Professor Gottshalg said Germany has too many solar panels which means that its grid is disrupted on sunny Summer lunchtimes with a flood of solar power so cheap it has to be almost given away.
He is urging to the UK to follow Germany’s recent policy of putting panels on east-west facing roofs to smooth the supply of power during the day and prevent spikes of power at midday.
Conventional wisdom in the northern hemisphere is to face solar panels south so they get the most exposure to sunlight during the day.
Architects and installers, as a rule, use this approach all the time particularly on home solar panel installations.
In November, American research revealed that panels facing west may actually get more energy from the sun, and at more convenient times.
The study was carried out by the Pecan Street Research Institute, who studied homes with solar panels in Austin, Texas.
Scientists found that when homeowners faced their panels west they were able to generate more electricity each day.
They also generated more electricity in the afternoon, when power grids experience peak demand.
Though the increase was small - just two per cent - experts said it would certainly add up over the years.
Add to this the afternoon boost, reducing grid dependence during peak hours by 65 per cent as opposed to 54 per cent for south facing panels, could have widespread efficiency implications beyond single homes.
Professor Michael Walls, of Loughborough University said: “There are half a million installations in the UK facing south. To maximise the amount of power produced by those panels, facing south is correct.
“What we are saying that if you have the solar panels facing east-west then you can even out the power during the day. You may lose about 10 per cent of power if you go east-west but this addresses a problem that exists in Germany where because everything is facing south, you get this peak power at midday which is very difficult for the grid to cope with.
“So in Germany they are advising people to go east-west so they are smoothing out the supply of power from all these solar panels. We get similar spikes of power too, although it wouldn’t make sense for people to change their solar panels if they have already been installed.
“In total we have 2.8 Gigawatts of solar in the UK but Germany has approaching 20 Gigawatts. In Cornwall they can’t install any more solar panels because the grid can't handle it.”
Solar panels are made up of photovoltaic (PV) cells that are layered in semi-conducting material, usually silicon.
When light shines on the cell it creates an electric field across the layers. The stronger the sunshine, the more electricity is produced.
In the UK, the average domestic solar PV system is 3.5 to 4kWp and typically costs from £5,500 to £9,500.
A 4kWp system can generate around 3,700 kilowatt hours of electricity a year – roughly equivalent to a typical household's electricity needs.
As well as this, households using a solar panel will be paid a minimum sum for all electricity generated by their system, known as the Feed-In Tariff (Fit).
The Fit currently stands at 14.38p per kilowatt hour (kwh) for each unit of electricity created, providing an income of around of around £785 a year.