So in February 2010 we decided to set an example and install our own. The roof of our offices in Highnam now supports two solar PV arrays, one facing south-east and the other facing south-west.
The panels cost Severn Wye less than £2,500 in investment – we were lucky to have support from the Low Carbon Buildings Programme (Phase 2) and the ScottishPower Green Energy Trust for the rest of the costs. This enabled us to install 28 panels covering around thirty-five square metres of roof space.
The rated capacity of the system is about 5.9 kWp – the maximum output under ideal conditions, which we sadly don’t get much of in Gloucestershire. Despite that, the system did reach its predicted energy yield more than three months ahead of schedule, and it’s still comfortably exceeding all our expectations. In the first year we got 950 kWh/kWp of output, and in the second year it got even better with 952 kWh/kWp of output.
Unfortunately, because we installed the system before the feed-in tariffs were introduced, we don't benefit from any FiTs payments. However, there are still plenty of benefits to be had from our array, and we reckon we've saved about £1,700 in energy bills since its installation, less than three years ago.
PV Data - 2013 to date
| Week Ending (FRI) | Cumulative Output (kWh) | Weekly Output (kWh) |
|---|---|---|
| 04 Jan | 16,216 | 27 |
| 11 Jan | 16,251 | 35 |
| 18 Jan | 16,286 | 35 |
| 25 Jan | 16,303 | 17 |
| 01 Feb | 16,367 | 64 |
| 08 Feb | 16,430 | 63 |
| 15 Feb | 16,467 | 37 |
| 17 Feb (Third Anniversary) |
Year Total = 5,309 | |
| Year 3 is down on the two previous years by around 5%, for a specific output of 903 kWh/kWp |
||
| 22 Feb | 16,553 | 86 |
| 01 Mar | 16,584 | 31 |
| 08 Mar | 16,658 | 74 |
| 15 Mar | 16,739 | 81 |
| 22 Mar | 16,809 | 70 |
| 29 Mar | 16,876 | 67 |
| 05 April | 17,015 | 139 |
| 12 April | 17,125 | 110 |
| 19 April | 17,244 | 119 |
| 26 April | 17,420 | 176 |
| 03 May | 17,622 | 202 |
| 10 May | 17,807 | 185 |
| 17 May | 17,939 | 132 |
| 24 May | ||
