PHOTOVOLTAICS

For Tree House to 'work like a tree', it must get all its energy from the sun. This specification led to the design of our big south-pitched roof, most of which is covered in photovoltaic (PV) modules. If my calculations are right, the amount of power we generate across the year on this roof will be enough to supply all our needs including driving the ground source heat pump in the winter.

The obvious problem with solar power, especially in a domestic context, is the poor match between supply and demand profiles. Consequently, we will be exporting our surpluses to the grid and buying it back when we need it. See my diary of 15.06.05 for more on this issue.

PV is a well-established technology but it remains expensive, even with a 50% government grant. In time, as costs fall and the pressure for renewable energy generation increases, it should become commonplace.

Our system is designed and installed by Solar Century: 020 7803 0100, www.solarcentury.co.uk.