Sample Savings
Electrical output of the installed system is dependant on three factors:
the size and number of panels
the orientation (the direction the panels face, with South facing panels being the most effective)
the pitch/angle of the installed panels (with the optimum angle being 35º)
The figures below indicate the typical savings likely to be achieved after installing a Freetricity Solar PV System within the M25(South should give you more savings, North less savings).
The figures below assume the installation faces due south, and is angled at 35º. Installations are described by their peak output (for example 4kW), but in calculating generation predictions, a factor of 0.91 of this figure is used to determine an annual kWh total.
For easy comparison, three typical sized systems are shown in the table below. Two columns show potential savings, depending on whether the household is likely to use 75% or 100% of the energy used (this relates to your lifestyle, and house usage during generating hours). Total savings over the 25 years, allowing for inflation of 4.5% are also shown. In addition, it is likely that energy costs will increase faster than inflation.
Sample savings examples
| System size (KW) |
Roof space required (m²) |
Annual output(kWh) |
Average Utility Unit Costs (£) |
Annual Savings where 75% of generated energy is used by household (£) |
Annual Savings where 100% of generated energy is used by household (£) |
20 Year Total Savings where 75% of generated energy is used by household (£)* |
20 Year Total Savings where 100% of generated energy is used by household (£)* |
| 2.5 |
18.3 |
2298 |
0.15 |
258 |
344.70 |
11,521.22 |
15,361.63 |
| 3.3 |
23.6 |
3033 |
0.15 |
341.25 |
455.00 |
15,208.01 |
20,277.35 |
| 4.0 |
28.8 |
3677 |
0.15 |
413.64 |
551.52 |
18,433.95 |
24,578.60 |
*Adjusted at an average annual inflation rate of 4.5%