In 2012, Roger installed a 16 panel, 4kwp solar PV system with financial support from the Feed in Tariff scheme. The panels have 15.1% efficiency and cover 26.5m2 of roof. Initially all the panels were installed on the rear south west facing roof, but following a house extension and agreed exceptions to Heritage Foundation design principles six panels are now located on a south east facing side elevation. The panels have delivered an average 3600 kwh a year, a little under the 3800 kwh predicted.
Roger loves his solar panels as his net annual energy bill for gas and electricity is around zero due to the Feed in Tariff! Unfortunately, this year the pigeons have found the gap between roof and panels is a great place to nest! Roger had an excuse to put on the safety harness and clamber round the roof to install stainless steel netting, something to think about at installation time!
Government data shows the average cost per kwh of small scale solar installations have fallen from £2080 in 2013 to £1628 in 2020. Feed in Tariffs have gone, but export tariffs of around 5p are available. With electricity costing 19p a kwh its clearly financially beneficial to use generated electricity to avoid importing rather than exporting electricity. This is where batteries have a role. Battery technology is improving and their costs are falling.
Back in 2012 Julia considered solar panels but Heritage Foundation design principles prevented a successful installation on the house roof. In 2021, with more efficient panels and lower cost batteries, a small installation on the hip shaped garage roof in the rear garden seemed worth exploring. The garage roof could support a 2kwp installation in a stepped shape, but the Heritage Foundation require a rectangular shape, so a 9m2, 1.8kwp system (20.2% efficient panels) has been agreed. Adding a battery will allow the majority of energy from the solar panels to be used by the household and purchasing electricity at nighttime rate to charge the battery and using this electricity during the day will reduce the household energy bill and make a small contribution to grid balancing. The rate of return over 25 years is 6.7%, with payback achieved at year 14.
St Albans District Council has agreed a solar streets project with the company IDDEA to help home owners install solar PV at lower than average costs. For each installation IDDEA make a contribution towards a fund to install solar PV on local community buildings. Transition Town Letchworth have asked NHDC if they can follow St Albans lead. Come and join Transition Town Letchworth if you want to be part of the shared local journey to zero carbon.