Should you put Solar PV on your house?
Solar PV (Photovoltaic) panels are panels that generate electricity from the suns radiation. Although the mechanism was discovered in 1839 by a French scientist Edmond Becquerel, it was not until 1954 that the first practical solar cell was developed, and not until the 1980s that solar panels started to be mass-produced. Since then, the price has plummeted such that currently, for large areas of the planet, solar PV is the cheapest way now to build new electricity generating capacity.
The History of the Feed in Tariff
Solar PV technology was supported in the UK by public subsidy between 2010 and March 2019 through the Feed in Tariff. Under this scheme, the owner of an qualifying solar PV installation would get paid a set tariff for each kWh generated for a 20 year period following the installation. The tariffs varied depending on the date and size of installation.
The tariffs started very high for early installations (about 40p/kWh for a 4kWh rooftop installation) and fell as the installation cost fell. Just before it eventually stopped, the tariff had fallen to a low of about 4p/kWh for the same size of installation. Tariffs for larger installations had lower tariffs.
In March 2019 the scheme was discontinued for new installations, but existing installations would continue to receive the tariff for 20 years from the installation date.
When the tariff was ended, there was significant concern that solar PV installations would grind to a halt, because PV could not support itself financially without subsidy. However, although volumes have fallen significantly, some solar PV installations can still be made to be viable.
Is it still a good investment to put PV on my house?
There are currently no state subsidies for the installation of solar PV panels, but installation prices have fallen so low that rooftop installations are still viable under the right conditions, primarily that much of the electricity generated will be used on site. As a rule of thumb, you would want to be sure that you would use at least half of the power on-site. That means using power during daylight hours. This may not be easy for instance if the whole household is out working or at school during the day, but for houses that are occupied during the day, may well happen.
A solar PV installation was carried out in Newtown in 2021 and documented in a case study which illustrates the costs and returns that you might expect. You can read this case study here PV Case Study