People often talk about solar panels when they mean photovoltaic panels: photovoltaic panels generate electricity and solar panels heat water. Solar panels are an altogether cheaper and simpler affair, but most churches have no way of using the large amounts of heated water except in Winter (when less of it is generated) and then only on occasional days.

The Diocese and the Diocesan Advisory Committee for the Care of Churches (DAC) are broadly in favour of self-generation where it can be achieved without aesthetic or significant visual harm or structural damage to the fabric of churches. It’s important to bear in mind that such installations on public buildings (including churches) almost always require Planning Permission, which may not be granted unless the installation is very benign. At an early stage in your discussions, you should start investigating whether your local authority has a policy on the matter, especially in relation to listed buildings. Most local authorities are also are broadly in favour, but their views will be strongly affected by the amount to which an installation will be likely to affect the amenity of neighbours, by how visible it is, and by how much it is likely to change the character of a Conservation Area.

However, the following issues will definitely be taken into account by the DAC when considering any application for photovoltaics.

  1. Will they be visible from ground level, and if so can they be disguised? A hidden roof behind parapets, or an invisible (but accessible) valley gutter may raise fewer planning issues.
  2. Will the particular location be shaded at certain times of the day by other parts of the church (like the tower or nearby projecting roofs) or by surrounding trees and buildings, which can significantly reduce the amount of generating capacity?
  3. How will they be attached to the roof? (If they damage it, then repairs when the panels are removed may prove more expensive than the value of the electricity you have generated. Some rogue installers have been discovered fixing them to the roofing battens, which is absolutely unacceptable).
  4. Will the roof structure withstand the extra load of very heavy panels (effectively very thick sheets of toughened and reflective glass) on only one side - not just the weight, but also the lifting/suction effect in high winds? This can be an important consideration on old or very large roofs, which were not engineered for the purpose.
  5. Has the cost calculation taken into account how the panels are manufactured and then disposed of when they cease to be useful? Some panels contain extremely harmful substances, and if the manufacture and disposal are seriously environmentally damaging, or if they have to be transported a long way and then go for land-fill, the net ecological value of the installation may be far less than one hopes, or even be more damaging overall.
  6. Is there space within the roof or elsewhere in the building to run the cabling and install the power exchanger without it being unduly intrusive?
  7. Can you maintain and clean the panels easily once they have been installed? Some types of panels attract algal growth, which must be cleaned off if the panels are to work efficiently for up to 25 years, and all are likely to require maintenance of some kind.

If your buildings have slate roofs, which are usually laid to a fairly steep slope, it might be worth investigating Solar Slates. These are small, textured photovoltaic panels which look convincingly like real Welsh slates. It might well be possible to cover all or part of a south-facing roof with them, or to add bands of them across the roof in a simple contrasting pattern – a common nineteenth century detail.

Ideally, all of these issues should be discussed with your Inspecting Architect, and with appropriate consultants who take a dispassionate view of all the facts. Once you have drawn up a draft scheme on professional advice, the next step would be to submit it for the advice of the DAC and the local authority. Do not proceed immediately to full faculty without taking as much advice as possible.

Photovoltaics can be useful for churches, but they do have their downsides. It is difficult to re-cycle the panels at the end of their useful lives without environmental damage, and recent government changes to the subsidised tariff probably mean that the cost projections and pay-back times given by installation firms will turn out to be over-optimistic.

In summary, although self-generation of electricity may seem like an obvious way to run your church on a stronger ethical and environmental basis, remember that the initial financial investment is likely to be very high in current financial circumstances. All new technologies have disadvantages, and the technology of self-generation is changing with astonishing rapidity. Within a few years it is likely that simpler and more efficient methods will have been developed, and in the mean time, you would be well advised to explore all the other ways you might begin to make your parish and its buildings more environmentally sustainable. However, the Diocese is keen to support environmental initiatives and we are happy to advise on the complex issues involved.

Phil Thomas, Church Buildings Officer & Graham Andrews, Archbishop's Adviser for the Environment.