Solar PV (electricity generation) is very different from solar thermal in terms of payback. Here we look at some typical payback periods for both technologies.
PV cells (Solar Electricity generation)
This is the area where most activity is happening at the moment. One of the benefits of fitting a PV system to your property is selling back the power you don't need back to the national grid, and being paid for it!! For example when you're on holiday,the Government will pay you for the power that you have generated, as it reduces the national grid's energy production requirement. The rate at which you are paid for the power you generate is known as the 'generation tariff'. The excess power you supply back to the grid is known as the 'export tariff' Both rates form the "feed-in tariff" introduced on April 1st 2010 in the UK.
In terms of payback for a solar thermal system, the easy, rule of thumb calculation is to assume that your solar system will deliver approx 60% of your hot water demands annually. Most panel manufacturers will claim this. Any claims higher than this, take with a pinch of salt - we live in the UK after all, and with solar, climate plays a big part!!
60% is an achievable figure based on a well designed, well insulated, south (or almost south) facing system.
However, what you need to consider is how much of your fuel bill goes on heating your hot water. In most households the figure is about 30% of your annual bill.
So: If your annual fuel bill is £1,000 30% of this will be for hot water, or £300 Solar will contribute to up to 60% of this, or £180
But... this is year in, year out, and as anyone who has had a solar system installed will tell you, there isn't a better feeling than
a)showering in the morning knowing that just the sun has heated the water, and b)turning your boiler off in May, and not turning it back on again until September (during summer, your solar system will usually be able to provide all of your hot water needs - yes, even in the UK!)
Another way of looking at it is this. If your house price only rises by 1% as a result of fitting solar (at worst it will be much more appealing to prospective buyers), then your system has paid for itself......Some observers don't believe that a solar thermal system affects house prices. That's as maybe, but if 2 identical, semi-detatched houses are up for sale, and the only difference between them is that one has a solar thermal system installed, giving free hot water and lower bills, which one would you buy?
Not to mention the CO2 savings, energy and the environmental impact your solar system will have.
Click here to read more about the feed in tarriff for PV solar panels
Return from 'solar payback' to the Home Page of UK Solar energy.org.uk