Generation predictions for both Solar PV and Wind Turbines are easy to do and give a fairly accurate estimate of the likely returns. The renewable industry is obliged to use government set figures for annual sunlight and wind levels, so estimates tend to be quite accurate if a little pessimistic.
We are finding that 90% of our installations are out-performing the pre-installation estimate.
So before making the final decision, compare the cost/payback estimates for several alternatives.
If you are considering an installation on a domestic property then there is little choice; provided you have a suitable South facing roof a 12 panel 4kW system is the best value for money.
Provided you are not a listed building or in an area of ‘outstanding beauty’ you do not require planning permission, but you do need building regulation approval.
If you don’t have a suitable roof and you have space then a ground mounted PV system could be the answer, or solar tracker, which follows the sun during the day and generates 40% more electric than a static system.
As you might expect it all depends on your location and your buildings.
The first choice for best value is still solar PV, but you do need a shade free, South facing roof, preferably with a 30% slope and strong enough to take the solar panels. Roofs slightly off South facings can still be viable so it is worth getting a returns prediction. If you have ground space, then a ground mounted PV system can be installed at the perfect angle. Planning permission is not required for roof mounted systems but is required for ground mounted.
For many commercial applications where it is not possible to mount panels on the roof a sun tracker can be an ideal solution. They can be installed in car parks or yards and generally don’t present any great problem with the planners. A 36 panel 13.3 kW tracker would produce a return in the region of £8,750 a year from an investment of £40,000. Multiple installations of these trackers are commonplace on the continent.
However, if you are located in a windy area then certainly wind turbines could be for you. Returns can be sensible for small turbines on sites with average wind speeds in excess of 4 m/s or 9 mph, investments start at £39,000 for a 5 kW.
Apart from finding the investment cash, the biggest problem with wind turbines is obtaining planning permission, so be prepared for a 6 to 12 month struggle with the planners before getting your answer.
HE Servicing provides a free of charge, no obligation, site evaluation survey, which provides you with a ‘cost/payback/returns’ estimate for all the above systems as well as guidance on system sizing and planning issues. Give us a ring on 01434 602402 to arrange this free survey.
