Solar storage heaters... Is it possible?

In principle using solar panels to charge storage heaters is an excellent idea to stay green and cut running costs. In reality there are a couple of factors which make it improbable.

Charging storage heaters with solar panels also means taking a charge during the day time instead of at night which can further complicate matters if you don't have a battery bank backup in your solar installation.

Typically a meter with solar panel generates a 100 Watts or 140 Watts. So you would need a lot of panels to even generate 1kW let alone enough KW to charge the storage heater for a full 7 hour charge cycle. A typical storage heater consumes about 2 – 4 kW. On top of that heating is very energy intensive compared to running other utilities.

Typically you should get about 110 - 140 Watts (peak output) from a square metre of PV Panel (photo voltaic), so about 7-9 square metres will give a kilowatt (1000 watts) of peak power output. ('Kilowatts peak' or 'kWp' is a measure of the maximum output you can expect under optimum conditions).

You can expect to get about 750-800 kilowatt-hours (kWh) per kilowatt of panels installed. This is about a quarter of the electricity used by a typical household. If you completely covered the south-facing roof slope of a typical terraced house with solar pv panels, you could probably get just over 2 kilowatts on, or about 1500 - 1600 kilowatt-hours per year.

Secondly the current issue with the cost of these panels makes it highly improbable unless you are backed by a government scheme for installing solar panels.

Installation costs are very high - typically around 15K GBP; so the government incentive schemes involving feed-in tarrifs etc. don't really stack up at the moment. Maybe when/ if the technology gets better and the installation prices come down - it might be more attractive.

So you could drive a storage heater if you completely covered your roof with panels, but it's doubtful that it makes economic sense (at the moment - 2012).