07 Dec 2010 04:12:15
PV still effective in winter weather
In spite of the phenomenal uptake in solar PV installation in the UK's domestic market over the past year, householders still have reservations about the effectiveness of this renewable energy source. The UK experiences 56% of overcast days throughout the year. If you combine that with a couple of severe winters, is solar PV a good investment in our climate after all?
Overcast days still allow sufficient light to travel through cloud cover to enable solar PV panels to operate. Although electricity production will only reach about 20% of what can be achieved on a day of clear skies and bright sunshine, this is still a decent amount of pollution-free renewably-sourced energy production.
The siting of your solar PV panels is important. Even through cloud cover, energy generation occurs. However, this is not so if the panels are placed in full or partial shade. It is therefore best to position your panels as close to a south-facing roof or other external location as possible. Avoid shade created by other buildings or trees, otherwise the panels simply won’t work.
The biggest question during our current polar cold snap is whether solar PV panels will work in the snow. Many people are surprised to discover that they do, although at a greatly reduced rate.
There are a couple of surprising fringe benefits to owning solar PV panels. The first of these is their ability to self-clean. Most panels are covered with a thin coating that allows rain water to flow neatly off the surface.
During smaller flurries of snow, your solar PV panels should continue to produce a small amount of electricity. During this process the panels will heat up slightly, so melting any thin layer of accumulated snow. The weather coating enables the melted snow to fall off the panels, so keeping them clear.
Some types of snow are particularly moist and will adhere to the panels in spite of the coating and the small heating effect. A very thin covering of snow still allows light to permeate onto the panels, so a small but significant amount of electricity is produced.
The problems come during periods of prolonged heavy snow. Several layers of snow accumulated on top of your solar PV panels won't cause them any harm. However, anything more than a thin covering won't allow any sunlight through, so the panels become inactive.
One solution is to brush the snow from the panels. If your solar PV panels are mounted independently in the grounds of your home, this should be a fairly straightforward process. However, if like most homes they are located on the roof, great care needs to be taken when attempting this job. Make sure that you don't put yourself in any physical danger by climbing ladders during harsh weather. If you do decide to remove snow from your solar PV panels, gently brush the snow aside. Don't use excessive force or attempt to remove any ice as this may cause damage to the panels. Ultimately it is better to do without renewable energy production for a few days, rather than injure yourself or damage your panels.