Solar Panels

Brenster

Hi All
I am considering investing in Solar Panels on my business roof. We are fortunate as we have a directly south facing roof on our premises with a surface area of aprox 150m2, so a significant potential for Solar Panels. We also benefit that we are next door to a electricity substation, might not be a factor but cannot do any harm in relation to the feed in wiring etc I presume.
I have had various options appraised based on the amount of panels we wish to invest in, and am getting quite healthy yield returns of between 15 - 20% (considering electricity usage savings, and feed in pay back) so we should have the panels pay for themselves in 6 years and then enjoy profit for the remaining 14 years of the 20 year guarantee. This all sound amazing, but if I am honest it seems a little too good to be true. Does anyone have any experience of solar panels? Also the feedback amounts are estimates, what is to stop companies over exaggerating these number to get a sale?? Any advise would be greatly appreciated.
Thanks in advance.

WestonDave

Best place for this question would be on the green and ethical board where all the solar panel owners hang out!

Most of the numbers are available to check for yourself regardless of what the suppliers say. Not sure if there are as many checks on a business contract as a residential one where their figures have to be on a standardised basis (and are conservative).

Depending on the size of the install you will get a certain amount per kWh generated - this is a national figure and easily googled - I can't tell you as you haven't said what size system you are thinking of!

There is then a online calculator http://re.jrc.ec.europa.eu/pvgis/apps4/pvest.php?lang=en&map=europe where you can plot your location and fill in various details about your system, size, angles etc and it will give you an independant estimate of the likely output from your system month by month. You can then use that with your FiT figure to work out how much you will get.

Savings on use are harder to work out because it depends on how much power you use when its sunny, whether you use power that will exceed your panels output etc. If you are running just lights and computers etc, quite a lot could be covered by the panels but it may be that quite a bit of generation goes off to the grid. If you are running a lot of heating devices, chances are you will exceed the panel output, but that probably means that on weekdays you will use most of what is generated. Sometimes best to look at this as a bit of a bonus as its hard to work out and make the main decision based on the Feed in Tariff elements.

Brenster

FYI we are looking at options between 20kw and 40kw. Thanks for your help.