Photovoltaic Systems

Home owners are increasingly aware of the impact that our energy consumption has on the environment, as well as the increasing financial cost of using that energy. Photovoltaic solar panels are becoming an increasingly popular way for home owners to produce some of their own energy in order to mitigate those bills, both financial and environmental.

Photovoltaic systems will produce electricity by way of semi conductors mounted in panels called a module, for which a number will be installed to make a solar array. The number of solar panels installed will depend on the occupier’s energy demand and ultimately the amount of roof space available. Ideally the panels should be facing somewhere between South East and South West and without shading, which can come from trees, chimneys or neighbouring buildings. East / West facing arrays are not ideal, but will show approximately 20% reduction in power output compared to a South facing array.

The amount of electricity produced will depend on the amount and type of modules installed. Systems that are commercially available range in efficiency from about 10-15%. This is not to be confused with the individual cell or array efficiencies, which will be higher. As with any electrical system, there will always be system losses. Therefore it will be important to understand the actual system output and cost of installation before deciding if is appropriate for a particular building. The solar panels produce electricity in a DC format. This will need to be converted into an AC format, so that it can synchronised with, and fed into the National Grid. This process occurs in an Inverter, which will usually be mounted in a garage or the loft. A credit meter is also installed to measure the amount of energy produced by the solar array. This is all then linked up to the consumer unit and then onto the utility meter. Unlike solar thermal systems, as long as the system is connected to the National Grid, any electricity not used by the building occupier is fed back into the Grid. For systems off Grid, batteries are used to store the energy produced.

Feed in Tariffs for Photovoltaic systems

For systems of up to 4 KW, this will pay a rate of 41.3 pence per KWh for any electricity that is generated. An additional 3p per KWh will be paid for any electricity that is fed back into the National Grid. There are also the savings to be made on your electricity bill by not importing electricity from the grid whilst the panels are in operation. The amount of savings will depend on the building occupier’s pattern of use. As a rough guide, a return of 8% should be achievable on the cost of an installation. The current Feed in Tariff rate is available to new customers until April 2012 and is paid for 25 years on an index linked basis. The rate for new customers after that will be 36.1 p per Kwh, again index linked for 25 years. However, given the current spending cuts there is a possibility that the April 2012 rate for new customers might be altered by the Government.

Why are these incentives being laid out?

It all relates back to the Government’s legally binding carbon reduction target of 80% by 2050. Photovoltaic panels are only 1 of a number of micro generation technologies that are available. Others include Solar Thermal, and Heat Pumps. The micro generation strategy is in itself only one part of the carbon reduction strategy. The framework is gradually being laid down by Government, which will also encourage us to use our energy more efficiently. This for example will encourage the replacement of old and inefficient appliances, such as fridges and washing machines for newer models which will consume less energy.

But a very significant part of carbon reduction, is that of wasting less energy, and this relates to the heating of buildings as much as anything else. By insulating loft spaces and cavity walls in accordance with current Building Regulations, building occupiers will be saving substantial amounts off their heating bills, simply by not wasting heat. There are of course many building occupiers who, whilst they can insulate their lofts effectively, cannot benefit from cavity wall insulation, because they have solid walls. This is something that the UK Government’s Green Deal is likely to address.

If you require any information on the installation and benefits of solar panels and other such technologies, please feel free to contact us or phone on 01636 525117.