Photovoltaics can save energy and money
Have my neighbours done this?
What is it?
They are mounted on your roof and generate electricity for use in the home and to sell
What will it save me?
Typically up to £700 per year including the feed in tariff depending on how many panels you have
How do I get it?
Needs to be installed by a specialist contractor
What does it cost?
Up to £7,000 depending on the panels
What are the technical details?
Over recent years there has been a dramatic increase in the number of homes having installed solar photovoltaic (PV) systems, largely due to the government initiatives to increase renewable electricity generation.
This is now an attractive investment opportunity because all electricity produced will result in an income for the house owner in the form of a Feed in Tariff (FIT) and the occupier will be able to use the free electricity in the home as well and receive an additional payment for the electricity exported to the grid (assumed to be 50% of the electricity generated).
It's also possible to heat hot water from the PV system by diverting spare electricity that would otherwise be exported, to the immersion heater in your cylinder, providing “free” hot water.
The PV system includes an array of photocells usually mounted on a south facing roof. This is connected to an inverter which converts the 12 volt DC electricity from the panels to 230 volt AC to be used in the house. This is connected through a meter to measure how much has been generated and fed into the household consumer unit. The meter reading is read and sent to the energy supplier who pays the Feed in Tariff but claims it back from the government.
There are several different types of photocells available but most are based on wafers of silicon which react to light and discharge electricity. Having the panels facing south and inclined at 30-45 degrees but not in shadow from trees or other buildings, provides the best opportunity to generate the most electricity from the available light. Direct sunlight provides the best conditions with generation tailing off when there are clouds.
Installing this type of system requires several skills and will usually require scaffolding to reach the roof. This is not a DIY job but is best done by a specialist contractor and electrician.