Solar Power

There are 7 main factors that affect how much power your installation can generate:

In the British Isles the optimal orientation for solar PV installations is South facing - in fact slightly West of that by 5 to 7 degrees.

East and West facing roofs can lose 10 - 20% of their effectiveness and North facing roofs a little more. Even northerly orientations are still worthwhile as the panels still work under daylight conditions.

When light levels fall below a certain threshold, the power output of a solar cell falls off rapidly. Higher quality panels will continue producing power at lower light levels so they produce electricity earlier in the morning, later in the evening and during particularly overcast days - such as those so often found in the UK!

Naturally enough, the ideal angle is pointing directly at the Sun, constantly - but motorised systems that track the Sun's movement are generally not economically worthwhile at the domestic level.

Daylight solar panels operate on overall lighting levels, so anywhere between 25 and 70 degrees from the horizontal will work well. Beyond these limits you can expect to lose up to 20% of the solar panels' effectiveness.

The further South you are the less atmosphere there is to block the Sun's rays. Also the thickness and nature of the atmosphere is important. In the British Isles, the nearer the South West you are - the more power you can generate. Solar panels still work in the North but not quite so efficiently.

The length of the day, the number of hours of sunshine, cloud cover and the number of rainy days, all affect the amount of power output from the solar panels.

These seasonal and climatic changes are no longer as important because the design of modern daylight solar panels has improved so much. However, these factors combined can still affect overall power output by as much as 30%.

We monitor the solar market place constantly and select the most efficient and cost-effective solutions for our customers' specific needs. At present we are favouring Jinko solar panels due to their high efficiency rating and cost. Jinko are one of few solar panel companies that manufacture their own solar panels.

Design is very important. The solar panels are strung together by wires. Each string is only as powerful as its weakest link because they are connected in parallel. If a single panel is not working optimally then the overall power drops like a kink in a hosepipe. The inverter, which collects and converts the electricity, typically has two inputs. This allows you to mix panels of different sizes in separate wiring looms (strings).

View one of our design overview sheets; it shows this in more detail.