Solar PV Still Cost Effective

A 4kWp system can generate around 3,800 kilowatt hours of electricity a year in the south of England – roughly equivalent to a typical household's electricity needs. It will save nearly two tonnes of carbon dioxide every year. A 4kWp system in Scotland can generate about 3,200 kilowatt hours of electricity a year – more than three quarters of a typical household's electricity needs. It will save more than a tonne and a half of carbon dioxide every year.

Location	System size	Feed-in-Tariff generation payment (£/year)		Feed-in-Tariff export payment (£/year)	Electricity bill savings (£/year)	Carbon dioxide savings (kgCO2/year)
		Valid between 1st April - 30th June 2015	Valid between 1st July - 30th September 2015
London, South England	4kWp	£510	£495	£90	£135	1,870 kg
Aberystwyth, Wales	4kWp	£480	£460	£85	£125	1,750 kg
Manchester, North England	4kWp	£450	£435	£80	£120	1,650 kg
Stirling, Scotland	4kWp	£425	£410	£75	£110	1,560 kg

The average domestic solar PV system is 4kWp and costs £5,000 - 8,000 (including VAT at 5 per cent). 

When Fits (Feed-in Tariff ) were first launched in 2010, a typical large domestic photovoltaic system cost £15,000-£18,000 to install. Early adopters were promised 41.3p per kilowatt hour (kWh) generated for 25 years, plus generous savings on their electricity bills worth up to £160 a year. Incomes and savings of more than £30,000 were promised for a £15,000 investment.

Price falls in PV panels over the past five years mean that the same system can now be installed for £5,000-£6,000 – and the government has responded by cutting the income paid accordingly. Those installing a system before 30 September this year now receive 12.92p per kWh if they live in a home that is energy performance certificate band D or above.

You still need a south facing, unshaded roof, ideally at a 45-degree pitch. Those who live in the south will get the highest income. Someone installing a £6,000 panel system on such a roof in Hertfordshire can expect an income and electricity bill savings of around £600 a year. Payments are index linked and are guaranteed for the next 20 years.

For an accurate calculation of how much your roof will generate use the EnergySavingsTrust calculator.