There are many many websites explaining PV - Photovoltaic - generation, but here are some links explaining it well, with a brief description of our own.
Energy Saving Trust / Solar Feed in Tariffs UK / Solar Century /
What are PV panels? Photovoltaic panels (PV) capture sunlight and daylight and convert it to direct current (DC). This can be converted to alternating (AC), providing your house with electricity and feeding the remainder to the Grid. A meter counts how much you generate. The panels are fine silicon wafer cells bonded to non-reflective toughened glass, enclosed in an aluminium frame. Photovoltaic panels can be mounted on your roof or wall, facing South or close to south. Roof is best, of course. Panels can be framed in aluminium and mounted as a complete panel, or they can be incorporated into facades or used directly as roof surfaces.
Can they meet my energy needs? A reasonable number of them arranged on a roof can provide ALL or most of your electrical power needs for the year, averaged over the year, but not when you need it most. This is done by using the Grid as a battery. During the Winter you generate little, but use all that you generate and import the rest from the Grid. During the Summer, you use little, and are mostly exporting to the Grid. Over a year it balances: the average British house will use about 3,400 kWh of electricity. A decent number of panels on a south facing roof will generate about 3,400 kWh of electricity. Bingo!
Can your roof take it? Well, if you have any areas of roof with an uncluttered surface that is facing South East, South or South West, and you are not overshadowed by high trees, then give it serious thought. The Author's roof faces East, but still generates enough to pay the entire energy bill, including heating. The market leading panel is 1m x 1.3m, and using these, the minimum you should consider is eight panels, the maximum 22. Any even number between will do.
Larger ones, or ones with higher output are available (see below)
Beware of Hipped roofs, they are more difficult to cover - but you can have arrays of panels on more than one hipped surface. Beware of considering PV roof tiles, they are far more expensive and less efficient than standard panels.
The usable amount of roof is very small? If you have a small roof but it has a good angle, then it is worth investing in higher output panels - so if you can only fit 8-10, you could get more electricity for the same costs of fixing, scaffolding inverter etc. by spending a bit more on the panels. Our estimates are mostly based on 240 Watt panels which will cover the same area of tiles.
Is my roof strong enough? If your roof is very old and fragile, and if you do not have underfelt, or you suspect rot in the timbers, undersized rafters, flaking tiles, slipping slates, chimneys about to shed pots or bricks, ridge or hiptiles about to fly..... do not continue! The panels last over 25 years and if your roof needs a significant refurbishment or felting sooner than 25 yrs it would be expensive to take all off, add felt, retile and refix panels. So do it now, then put the panels on after. On the positive side, a mesh of strong alloy rails attached to your roof will make it stiffer, and the rainscreen effect of the panels will protect your roof against future weathering - but the roof must be sound in the first place.
I've got houses / trees south of me - is it worth it? If you can draw an imaginary line 15º of elevation from your roof, and it clears the houses you have sufficient view of the sun. If you don't it may still be worth doing, because the entire harvest from December or January is only the equivalent of 2 or 3 nice days in June or July. So a long winter shadow is not a great problem. Consider a line of 30º elevation from your roof position - let's hope that is clear. So if you think that there is something that causes concern ask your solar surveyor for advice.
Does the UK have enough Sun for PV to be practical? The naysayers say no, but are too timid to try it... or they haven't yet heard about the Feed in Tariff. Those who have installed have found that it works. While we can grow grapes and make wine in England, we can also grow electricity! The further south you are, the more sunshine you get, but you can partially compensate for your latitude by getting the roof angle right.
If you are building a new house, give priority to providing a south facing roof of 30-40 degrees of slope, and 30 sq.metres of clear, unshaded surface, ideally.
Do they work from Daylight as well as from Sunlight? Yes they do, but only 1/5 to 1/10 as much power as when direct sunlight is on the panels. If your panels are on an east roof and the sun is in the west, you are still getting power from the bright sky - but not a lot....
Other FINANCIAL Questions - see the "Financial" Tab
Energy Saving Trust / Solar Feed in Tariffs UK / Solar Century /
What are PV panels? Photovoltaic panels (PV) capture sunlight and daylight and convert it to direct current (DC). This can be converted to alternating (AC), providing your house with electricity and feeding the remainder to the Grid. A meter counts how much you generate. The panels are fine silicon wafer cells bonded to non-reflective toughened glass, enclosed in an aluminium frame. Photovoltaic panels can be mounted on your roof or wall, facing South or close to south. Roof is best, of course. Panels can be framed in aluminium and mounted as a complete panel, or they can be incorporated into facades or used directly as roof surfaces.
Can they meet my energy needs? A reasonable number of them arranged on a roof can provide ALL or most of your electrical power needs for the year, averaged over the year, but not when you need it most. This is done by using the Grid as a battery. During the Winter you generate little, but use all that you generate and import the rest from the Grid. During the Summer, you use little, and are mostly exporting to the Grid. Over a year it balances: the average British house will use about 3,400 kWh of electricity. A decent number of panels on a south facing roof will generate about 3,400 kWh of electricity. Bingo!
Can your roof take it? Well, if you have any areas of roof with an uncluttered surface that is facing South East, South or South West, and you are not overshadowed by high trees, then give it serious thought. The Author's roof faces East, but still generates enough to pay the entire energy bill, including heating. The market leading panel is 1m x 1.3m, and using these, the minimum you should consider is eight panels, the maximum 22. Any even number between will do.
Larger ones, or ones with higher output are available (see below)
Beware of Hipped roofs, they are more difficult to cover - but you can have arrays of panels on more than one hipped surface. Beware of considering PV roof tiles, they are far more expensive and less efficient than standard panels.
The usable amount of roof is very small? If you have a small roof but it has a good angle, then it is worth investing in higher output panels - so if you can only fit 8-10, you could get more electricity for the same costs of fixing, scaffolding inverter etc. by spending a bit more on the panels. Our estimates are mostly based on 240 Watt panels which will cover the same area of tiles.
Is my roof strong enough? If your roof is very old and fragile, and if you do not have underfelt, or you suspect rot in the timbers, undersized rafters, flaking tiles, slipping slates, chimneys about to shed pots or bricks, ridge or hiptiles about to fly..... do not continue! The panels last over 25 years and if your roof needs a significant refurbishment or felting sooner than 25 yrs it would be expensive to take all off, add felt, retile and refix panels. So do it now, then put the panels on after. On the positive side, a mesh of strong alloy rails attached to your roof will make it stiffer, and the rainscreen effect of the panels will protect your roof against future weathering - but the roof must be sound in the first place.
I've got houses / trees south of me - is it worth it? If you can draw an imaginary line 15º of elevation from your roof, and it clears the houses you have sufficient view of the sun. If you don't it may still be worth doing, because the entire harvest from December or January is only the equivalent of 2 or 3 nice days in June or July. So a long winter shadow is not a great problem. Consider a line of 30º elevation from your roof position - let's hope that is clear. So if you think that there is something that causes concern ask your solar surveyor for advice.
Does the UK have enough Sun for PV to be practical? The naysayers say no, but are too timid to try it... or they haven't yet heard about the Feed in Tariff. Those who have installed have found that it works. While we can grow grapes and make wine in England, we can also grow electricity! The further south you are, the more sunshine you get, but you can partially compensate for your latitude by getting the roof angle right.
If you are building a new house, give priority to providing a south facing roof of 30-40 degrees of slope, and 30 sq.metres of clear, unshaded surface, ideally.
Do they work from Daylight as well as from Sunlight? Yes they do, but only 1/5 to 1/10 as much power as when direct sunlight is on the panels. If your panels are on an east roof and the sun is in the west, you are still getting power from the bright sky - but not a lot....
Do I need planning permission?
Where does my electricity go to? Well your neighbours may not know it, but your clean energy goes to them! They pay their supplier a standard import price of 12.5-13p a kWh, but a tiny percentage of what they pay is going towards your Feed in Tariff payment.
What effect does this have on my lifestyle? Conventional electricity users are used to the idea of the Economy 7 tariff, doing the washing machine and storage heating at night. Photovoltaic generators are the opposite! You calculate the peak time of sunlight capture (for the author it is 1045 am), so we run the washing machine or dishwasher, do the ironing and make a decent cup of tea between 1000 and 1200.
For most areas, since 2008, the planning rules have been relaxed so that alternative technology solutions (such as PV panels or solar thermal) are usually deemed to be 'permitted development' unless they project more than 200mm from the roof or wall surface. The Town and Country Planning amendment document explains the rules more fully.
A polite visit or exchange of letters with the planning officer (not a full fee-paid application) is usually enough to re-assure you that you can proceed. It is unlikely that neighbours will object to the appearance. Recent installers favour panels with Black frames that are less obtrusively metallic than the earlier panels.
Conservation Areas are 'areas of special architectural or historic interest, the character or appearance of which it is desirable to preserve or enhance'. In the conservation area, the Borough Council have control over the demolition of buildings and can enforce policies designed to preserve or enhance all the aspects of character or appearance that define that area's special interest. That does not totally prohibit changes, it just means that they have to be well designed and must gain approval. (Section 69 of the Civic Amenities Act 1967)
There are 29 conservation areas in Rushcliffe (e.g. Edwalton village). Rushcliffe's website lists the conservation areas, and the rules applying to conservation areas. (They are not against them in principle, you just have to be smarter about positioning them, eg, avoiding defacing prime views of the building). In this case an application would be required, but your solar installer (or Solar Rushcliffe) could help with a photo-montage to display how the panels might look. If for some reason you discontinue using your solar panels, you are requested politely to remove them, to restore the appearance of the building.
Thomas Street tstreet@rushcliffe.gov.uk is the conservation officer for Rushcliffe Borough and can answer detailed questions on this.
Listed Building If you have one of these, you have a higher planning threshold to jump, although all Local Authorities recognise the need to respect the movement towards energy sustainability. It may be possible to provide solar power in a discreet way (e.g. in a roof valley). This needs to be discussed with your conservation officer. Older buildings may also have fragile rooftiles that discourage adding any further weight.
A polite visit or exchange of letters with the planning officer (not a full fee-paid application) is usually enough to re-assure you that you can proceed. It is unlikely that neighbours will object to the appearance. Recent installers favour panels with Black frames that are less obtrusively metallic than the earlier panels.
Conservation Areas are 'areas of special architectural or historic interest, the character or appearance of which it is desirable to preserve or enhance'. In the conservation area, the Borough Council have control over the demolition of buildings and can enforce policies designed to preserve or enhance all the aspects of character or appearance that define that area's special interest. That does not totally prohibit changes, it just means that they have to be well designed and must gain approval. (Section 69 of the Civic Amenities Act 1967)
There are 29 conservation areas in Rushcliffe (e.g. Edwalton village). Rushcliffe's website lists the conservation areas, and the rules applying to conservation areas. (They are not against them in principle, you just have to be smarter about positioning them, eg, avoiding defacing prime views of the building). In this case an application would be required, but your solar installer (or Solar Rushcliffe) could help with a photo-montage to display how the panels might look. If for some reason you discontinue using your solar panels, you are requested politely to remove them, to restore the appearance of the building.
Thomas Street tstreet@rushcliffe.gov.uk is the conservation officer for Rushcliffe Borough and can answer detailed questions on this.
Where does my electricity go to? Well your neighbours may not know it, but your clean energy goes to them! They pay their supplier a standard import price of 12.5-13p a kWh, but a tiny percentage of what they pay is going towards your Feed in Tariff payment.
What effect does this have on my lifestyle? Conventional electricity users are used to the idea of the Economy 7 tariff, doing the washing machine and storage heating at night. Photovoltaic generators are the opposite! You calculate the peak time of sunlight capture (for the author it is 1045 am), so we run the washing machine or dishwasher, do the ironing and make a decent cup of tea between 1000 and 1200.
Will these heat my hot water? Photovoltaic panels are quite different from Solar Thermal. They make electricity. There is a huge difference in scale. 2-4 sqm of solar thermal panel is enough for one house, but photovoltaic may require up to 28 sqm to be fully effective. The two can be mixed on the same roof slope, but if you want to split them, put the PV on roofs that are more east or south facing, and solar-thermal on west facing. Solar thermal can tolerate a bit of shade or heat, but PV panels must be unshaded and cool.
There are some combination panels available in the US, indeed the author has designed one of his own, but they are not available in the UK for accredited installations, and would be fearfully more expensive than using the market leading panels specific for each purpose - electric generation and solar heating.
Is it better to have Solar thermal panels? You are welcome to do both if you have enough roof, and want lots of hot water. Solar water heating panels spend much of their time in 'stasis' when they have stored enough heat in the water tank and it cannot get any hotter, i.e. if nobody is using the hot water, they do nothing. There is a surplus of hot water when you don't need it in summer, and not enough when you do, in the months of winter. They will reduce your Hot water heating bill, annually, although this totals only about 25% of the annual heating bill.
(In the author's house we take showers, not baths, as Water Saving is also part of our energy efficient ethos - so a Solar Thermal panel would be uneconomic. But because we are avid to try every method of saving energy, we do actually have solar thermal panels mounted on the wall which are used to heat the water AND the house. - ask the author for more information on how to do this.)
Solar PV panels store their harvest in the Grid which is infinitely elastic, so they continue to work and make income for you even when you are on holiday or at work.
There are some combination panels available in the US, indeed the author has designed one of his own, but they are not available in the UK for accredited installations, and would be fearfully more expensive than using the market leading panels specific for each purpose - electric generation and solar heating.
Is it better to have Solar thermal panels? You are welcome to do both if you have enough roof, and want lots of hot water. Solar water heating panels spend much of their time in 'stasis' when they have stored enough heat in the water tank and it cannot get any hotter, i.e. if nobody is using the hot water, they do nothing. There is a surplus of hot water when you don't need it in summer, and not enough when you do, in the months of winter. They will reduce your Hot water heating bill, annually, although this totals only about 25% of the annual heating bill.
(In the author's house we take showers, not baths, as Water Saving is also part of our energy efficient ethos - so a Solar Thermal panel would be uneconomic. But because we are avid to try every method of saving energy, we do actually have solar thermal panels mounted on the wall which are used to heat the water AND the house. - ask the author for more information on how to do this.)
Solar PV panels store their harvest in the Grid which is infinitely elastic, so they continue to work and make income for you even when you are on holiday or at work.
Other FINANCIAL Questions - see the "Financial" Tab
