By Ian Blake
Associate director, Sutton Griffin Architects
Domestic wind turbines only work well in some areas
How many people are actually going to be able to install renewable energy-generating technology in their homes?
That is the burning question which goes unanswered in the government's strategy document called "Warm Homes, Greener Homes", which outlines how it plans to cut carbon emissions from homes by 29% by 2020.
The plan includes helping as many households as possible install loft and cavity wall insulation within the next five years, and fitting seven million homes with solid wall insulation or renewable energy-generating technology such as solar panels or wind turbines by 2020.
This is a major commitment by the government, but while the document goes into detail about how it intends to deliver on this commitment, it does not really answer the question about how it will work.
For example, will a wind turbine work in the middle of a housing estate?
And, in a country that is hardly known for year-round sun, is it feasible that millions of homeowners can rely on solar electricity systems to power their homes?
Much has been written on the theory of renewable energy-generating technology in the home, but what about the practice?
Bring me sunshine
It is a misconception that solar electricity systems, which convert sunlight into electricity by capturing the sun's energy using photovoltaic (PV) cells, need direct sunlight.
The PV cells can actually generate electricity on a cloudy day. However, the cells do need to be installed on a roof or wall that has an aspect that is within 90 degrees of south and is not overshadowed by buildings or trees.
Any shadow on the cells during the day will decrease the output of the system.
Then there is the issue of attaching the PV cells. The cells need to be attached to either a roof or wall strong enough to take their weight. They are not light and it is definitely worth checking with a qualified installer before proceeding.
If you live in an apartment and do not have roof access, then you will need your landlord's permission before mounting PV panels on the roof and connecting a cable from the panels to your flat. This is likely to be an issue with older, high-rise buildings.
Wind turbines generate electricity by harnessing the power of the wind. There are two types of domestic small wind-turbines: mast-mounted, which are free standing, and roof-mounted, which can be installed on the roof of a home.
Ian Blake believes that the devices will not suit every homeowner
Small wind turbines work best in exposed locations where there are no large obstacles like other houses, trees or hills, so this immediately rules out a large number of properties in urban and suburban areas.
Also, to work effectively, wind turbines need an average wind speed of no less than five metres per second, which counts out many areas of the UK. The ideal location is a smooth-top hill, with a flat, clear exposure, free from excessive turbulence and large obstructions.
In April 2008, the government relaxed the planning requirements for the installation of domestic microgeneration equipment, although permission is still needed from the local authority to install a domestic wind turbine.
This is not the case for solar electricity devices as long as they are below a certain size, although it is worth checking with the local planning office if your property is listed or in a conservation area or World Heritage site.
If the property is a listed building it is likely to require an application for listed building consent, even where planning permission is not required.
It is worth noting that these permitted development rights only apply to houses. Flat owners will need to make a planning application for any outside installations.
The cost of installing a solar electricity system can be anything from £8,000 to £14,000 depending on type and size. Also, PV panels that are built into a roof will cost more than those that sit on existing roof tiles.
Solar panels do not require planning permission on houses
Again, domestic wind turbines are not cheap, although a roof mounted system can be purchased from as little as £1,500. Larger mast-mounted systems are a lot pricier, costing between £10,000 and £19,000.
To install PV panels you will need a MCS (Microgeneration Certification Scheme) electrician. The existing electrical meter will also have to be replaced with an input/output meter, and cable connections will be required from the roof to the meter.
This will cause some minor disturbance to the fabric of the house, such as lifting of floorboards and drilling holes through walls.
The homeowner will also be required to satisfy Part P of the Building Regulations (electrical safety), which, like the planning application, will involve a fee.
Fortunately, PV panels need very little maintenance, other than being kept relatively clean and free from any shade from trees growing nearby.
The wiring and components of the system need to be checked regularly by an MCS-qualified electrician, who will require access to the panels. Depending on location and property, this could involve temporary scaffolding.
As for wind turbines, maintenance checks are advisable every few years, and a well-maintained turbine should last more than 20 years. You should also consider insuring your equipment, whether solar or wind. Your existing home insurance company may offer cover but if not try a specialist insurer.
For many homeowners, location, property type and the wrong weather conditions will make solar panels and wind turbines completely impractical as a green solution for their properties, irrespective of cost.
And for those who can benefit from this energy generation technology, many will consider the savings made are not impressive enough to justify the effort and expense, even with the help of the government's "green loan" scheme that is intended to circumvent the punitive up-front costs.
Although eco-makeovers will be right and convenient for some, for the majority of us the practice of installing energy generation technology is lagging behind the theory.
We are moving in the right direction, that much is sure, but it could be a few more years before people can make a seamless transition to domestic renewable energy generation.
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