The picture above shows both solar panels (for electricity) and, higher, up a solar hot water installation. Both are facing southwest. It is important in both cases to have them facing somewhere between southeast and southwest (south is ideal) and to minimise shading by chimneys, trees or other buildings. There is also an optimum tilt (angle to the vertical), in order to maximise the amount of light collected, which is close to the angle of the roof in many cases. (The hot water panels above have been provided with a tilted support, because they couldn't fit on the roof.)
The amount of energy collected is maximised by choosing a good direction and tilt. In both cases no energy is available at night (or occasionally a tiny amount from moonlight.) It is possible that the light will also be too low during a severe thunder storm. SOLAR PANELS FOR ELECTRICITY
Solar (photovoltaic) panels can be used to generate electricity from sunlight. The panels in the picture at the top on the right are facing southeast. Here some of them are shaded, because it is later in the day and the sun has already reached the southwest. When the sun is at such an oblique angle to the panels, not much electricity will being generated. When the sun is closer to the south, none of the panels is shaded and they will all be generating. The electricity is fed into the grid, unless it is used in the house while it is being generated. Then the electricity is free, so it makes sense to run your electrical equipment while the panels are generating. The price the electricity supplier pays you for the electricity is much lower than what you pay them! Martyn: "Our panels once switched off during a very bad storm but normally they generate for a good part of the day. The inverter [which converts the electricity to feed in to the mains] is in our hall, so we can see easily how much we are generating at any time." N.B. If there is a power cut, then the solar panels will not be able to feed in the electricity to the grid. So, unless you have a battery as well to store it, the electricity generated can't be used. |
The panels above were installed a number of years ago when the government provided a large feed-in tariff (because the panels were very expensive). Now the price of solar panels is lower and there is no longer a feed-in tariff.
Jonathan: "The panels in the photo bring us about £900 a year, but we are on an early government scheme subsidy [feed-in tariff] which is no longer available."
Janet: "Don't make our mistake. We didn't notice our wisteria growing onto the roof and over the solar panels. Luckily, its removal could be combined with gutter repairs. We now keep a good eye on the wisteria." |
SOLAR HOT WATER
Energy from sunlight can also be used to heat hot water.
Energy from sunlight can also be used to heat hot water.