Solar power is an abundant source of energy: approximately 2.67 kWh per m2 per day reaches the Earth’s surface. That 89 petawatts (add 15 zeros) of sunlight reaching the Earth’s surface. It is is almost 6,000 times more than the 15 terawatts (12 zeros) of estimated power consumed by humans. The problem is how to harness, store and transport it.

Solar collectors can be especially effective in the South of England, as can be seen from this diagram showing Annual Total kWh/m2 – dark red represents 1200KWh/m2 and the lightest area 900 KWh/m2. A collector on your home can be linked directly to heat, water and/or power and even provide lighting dependant on the installation. You could harvest comfort and energy independent of the national grid, ie ‘free’ once installed. It is of course dependent on the light level (not the heat) supplied by the sun, so battery storage is becoming the new target technology.

Also in theory you can gain by selling spare power back to the national grid so there are huge possibilities of developing power swaps in electrical transport, solar farms, hydro power etc to replace dirty electric power generation. This is not ‘blue sky thinking’, the technology is available, but it needs political support to develop at feasible scale.

Heat map of the UK

Heat map of the UK

There are many different types of solar panels in production, and can now be spotted on domestic roofs. The most common types installed by the building trade are: photovoltaic, flat panel and evacuated tube solar panels. The first type generates electricity, the second is mostly superceded now, the third is usually provided to supply hot water for heating systems and domestic use via a heat store cylinder.

A decade ago there was a burst of popularity and a new industry around solar installations for the domestic market developed quickly. Then the ‘feed-in-tarriff’ – rewarding householders for supplying electricity to the national grid or reducing demand by replacing the need for gas with solar-heated water – was progressively reduced to near-zero and installers closed down.

However where the investment is feasible, especially for larger commercial installations, including from solar farms, solar technology is developing fast and is yet another industry awaiting massive take-off under the universal phrase “Green New Deal”.