4kw Solar Panel System – Estimation of Costs and Benefits
The 4kw solar panel system usually consists of solar panels ideally mounted on a south facing roof. It should generate around 3400 kwh per year depending upon it’s geographical location.
A three bed house uses around 3000 kwh per year of electricity. So whilst you can expect to generate all of the energy your household requires, you will still need to rely on the National Grid during the evenings and when energy generation is intermittent due to poor weather conditions. There will also be instances when more energy is required than being generated like when using a dishwasher, washing machine or electric oven.
Any excess energy created can be sold back to the National Grid.
a). No allowance has been made for the cost of maintenance of the system. The estimated lifespan is 25 years however no allowance has been made for the decline in performance as the solar pv system ages.
b). Benefits may increase or decrease depending upon the fluctuation of your local electricity suppliers prices. An increase in the mains electricity price means the benefits of having solar panels will increase. But a reduction in electricity prices means your solar benefits decrease.
c). A 4kw solar electricity system requires approximately 28 square metres of roof space. You should consider whether the appearance of the solar panels may affect the value of the property in the event of selling the building in the years ahead.
4kw Solar Electricity PV (Photovoltaic) System Cost Analysis
Estimated cost of System £7500 (the cost of systems have reduced significantly recently which means the payback period has shortened)
4kw solar system creating approximately 3400 kwh of electricity per annum = £476 (calculated at 14p per kwh – estimated value of best local electricity company tariff)
Feed in Tariff (Government Benefit) @ 16p per kwh generated = £544 (inflation may reduce the value of this benefit over the long term unless it becomes index linked)
Exported electricity not used (currently @ 4p per kwh)
Total Annual Benefit £1020
Payback Period: 7 years 4 months