Solar PV Frequently Asked Questions
Does my roof have to be South Facing? Ideally yes, but solar panels work well on East & West facing spaces too. The yield will reduce compared to South/South-East/South-West but we can show you the implications of this (using SAP, see below) and allow you to make a decision accordingly.
What is the Feed-in-Tariff (FIT)? The Feed-in-Tariff is a government agreed pricing structure for the generation of electricity from certain renewable technologies including Solar PV. It guarantees a rate for generation (21p per kWh currently), a rate for exporting solar electricity (3.1p per kWh) and the rate for future increases (RPI) to give consumers a full understanding of the potential gains over the lifetime of solar ... more details here
Solar Thermal vs Solar PV. What's the difference? Solar Thermal heats up water and therefore reduces the energy required from traditional heat sources. Solar PV turns the light into electricity.
Solar thermal does not currently attract any Feed-in-Tariff (FIT), whereas Solar PV does. UPDATE Solar Thermal will benefit from FIT's but from October 2012.
Are there grants for installation costs of Solar PV? No, not any more. They have been replaced by the Feed-in-Tariff. The Feed-in-Tariff does offer a better 'return on investment' compared to the old grant scheme but this does make the up front costs larger. But overall it's better for the consumer now for the lifetime of the PV installation.
I keep seeing reference to SAP numbers. What are they? SAP is Standard Assessment Procedures for the UK. For Solar PV it is a way showing how much energy could be produced from Solar PV panels depending on a host of issues.
These figures average out the great and lousy weather conditions, issues of shading and orientation to give a realistic/justifiable yield for Solar PV installations; figues that have been agreed by the governing body for renewable energy - the MCS.
The key point is that they are standard. Every MCS Approved Installer has to (or should) use these SAP figures as the basis of their calculations and presentations to customers. It stops any over-enthusiastic claims of efficiency being used which might mislead the customer as to the real Return on Investment. When installers drift into non-standard numbers consumers can no longer compare, like-for-like, between one installers offerings and another.
How many solar panels could I have? That depends on the roof area and its direction and level of shading. However, if you imagine the average panel is 1m x 1.65m you can perhaps estimate the capacity of your own roof space.
What if my roof is shaded or partly shaded? Modern Solar PV panels can cope with shading or partial shading better than its early counterparts, but it isn't ideal. Again we can show you the implications of shading using agreed SAP figures (see above for SAP)
What is the return on investment for Solar PV? That depends on the number of panels, their direction, shading and of course how much you pay for the system in the first place. But figures of 8-10% per annum are realistic and achievable using SAP numbers and a realistic pricing of the installed system.
What about the green benefits of Solar? The green affect is a reduction in carbon emissions for electricity generated by Solar PV. The Feed-in-Tariff scheme will also create an industry of suppliers and installers serving an ever larger number of customers - hopefully accelerating the use of not only Solar PV but an array of green technologies which can fit into even more peoples lives.