How Solar Photovoltaic (PV) Works

The "photovoltaic effect" is the basic physical process through which a PV cell converts sunlight into electricity. Sunlight is composed of photons, or particles of solar energy. When a photon is absorbed by a PV cell the energy of the photon is transferred to an electron in an atom of the cell (a semi conductor). With its newfound energy the electron is able to escape from its normal position associated with that atom to become part of the current in an electrical circuit.

PV cells are grouped into modules and encapsulated between a sheet of glass and a backing material (also often glass) within a frame. Modules are connected together (into an 'array') to provide the voltage and DC current levels required to meet a particular load.

Within PV systems for homes, the electricity produced by the PV array is converted from DC to AC and is connected with the home's mains electricity system.

Once installed on a roof the PV system generates clean electricity whenever there is daylight and feeds it into the building’s electricity supply to power lights and appliances. It does not have to be direct sunlight, although the more intense the light, the higher the electrical power produced at any time. The building remains connected to the national grid, and when more electricity is generated than is being used, the excess flows into the grid. When the PV system is not generating enough electricity – like at night time, electricity is drawn from the grid as normal.

PV systems are unique in that they can be mounted on buildings to produce electricity at the point of demand without any adverse environmental effects - no noise, no moving parts, no exhaust gases and no dangerous by-products.

Apart from reducing carbon emissions and electricity costs, our experience shows that installing a PV system has a wider effect on electricity usage in the building. As occupants are able to monitor what their solar electric systems produce, they normally find they start using less electricity because of their new awareness of the resources that they are using.

News

1 February 2010

Government Confirms Feed-In Tariff Cash Rewards for Solar PV

The Government has announced higher than expected cash rewards for low carbon electricity produced by solar photovoltaic (PV) systems through the new Feed-in Tariff scheme.

With effect from 1st April the Feed-in Tariff (also known as the "Clean Energy Cashback" scheme) will be introduced whereby an annual payment will be made to PV system owners for electricty generated and exported for 25 years.

The tariff levels have been set higher than previously revealed in the Government's consultation document published in Autumn last year. A typical household retrofit PV system under 4 kilowatt (kW) will receive 41.3p per kilowatt hour (kWh) with an additional payment of 3p per kWh for any electricity exported back to the national grid. Taking into account the additional avoided costs from having to buy less electricity from electricity companies, it is estimated that homeowners can save and earn over £1,000 per year for 25 years with a typical solar PV system.

Until 31st March, homeowners are also able to access a Government grant of up to £2,500 to help with upfront costs, meaning that there has never been a better time for households to start generating their own electricity.

To find out more about our solar PV systems and the financial incentives available click here.

0% business loans for equipment upgrades

Borrow £3,000 to £500,000 at 0% interest

Is your old equipment making your business uncompetitive? Or is it simply costing a fortune in energy bills? Inspect can help! We have recently been granted Carbon Trust approval. This means we can help your business shrink its carbon foot print and reduce costly overheads. Through us you can apply for an interest free loan.

The unsecured loan that can pay for itself

Carbon Trust business loans are unsecured and interest free, with no arrangement fees and a straightforward application process. Loans can be repaid over a period of up to four years and as the scheme is designed for energy savings to cover repayments, the loan will effectively pay for itself.

To find out more call us on 029 20 611 277 or fill out our online enquiry form and we’ll get back to you.

Payback?

Pay back Renewable energy 'payback' is a controversial issue that never gets properly explained. We look at it like this:-

If you have a perfectly good system and are looking to go green then good for you for reducing your carbon emissions but don’t expect to achieve payback any time soon! Some systems can be modified to incorporate renewable energy but they are never as efficient as a new bespoke energy saving installation.

If you have an old failing system and are looking to replace it or are installing a hot water and heating installation in a new property then you only have to pay a little extra to include renewable energy. Payback could be achieved in a few years - how quickly depends on how you use your heating and hot water.

If you intend selling your house then a renewable energy installation would be an attractive feature that would be sure to entice buyers. They would certainly benefit from your outlay and enjoy free renewable hot water and central heating!

What is Part P of the Building Regulations?

In 2005 the Government introduced electrical safety rules into the Building Regulations for England and Wales. Because of this, most fixed electrical installation work carried out in homes must, by law, meet the Building Regulations.
Part P states that anyone carrying out electrical installation work in a home must make sure that the work is designed and installed to protect people from fire and electric shocks. Part P applies to newly-built homes and to any changes made to existing installations, including any parts that have been rewired.
You can find full details on Part P on the Communities and Local Government website on our useful links page.

What electrical work is covered by this law?

All electrical installation work in a kitchen, bathroom, garden, conservatory or outbuilding must meet the Building Regulations. Apart from some types of minor work, all electrical work must either be reported to the local-authority building-control, or be carried out by an electrician who is registered with one of the Government-approved scheme providers.

Who is responsible for making sure that electrical work meets the requirements of Part P?

By law, all homeowners and landlords must be able to prove that all electrical installation work meets Part P, or they will be committing a criminal offence. Local authorities can make homeowners or landlords remove or alter any work that does not meet the Building Regulations.

What do I need to do before electrical installation work can be carried out in my home?

You must either:
1. tell your local-authority building-control about the installation work before it starts; or
2. employ an electrician who is registered with one of the Government-approved Part P schemes.
We recommend that you use a registered electrician to do the electrical installation work.

The advantages of using a registered electrician are:

• you will not have to pay any building-control charges;
• the electrician can deal with everything for you;
• the electrician will arrange for you to receive a certificate that confirms the work meets Building Regulations;
• you have access to a formal complaints procedure if the work doesn’t meet Building Regulations; and
• you can choose to take out an insurance-backed guarantee when you have the work done, and you can make a claim if the work is later found not to meet Building Regulations.

What does Part P of the Building Regulations mean for me?

If you use a registered electrician, you can expect to have safe electrical installation work done, as the work will meet the UK national standard, BS 7671 (Requirements for Electrical Installations). When the work is finished you will receive:
• an Electrical Installation Certificate or Minor Works Certificate that confirms that the work meets BS 7671; and
• a Building Regulations Compliance Certificate that confirms that the work meets the Building Regulations.

Is it important who carries out electrical installation work in my home?

Yes. Electrical installation work must be carried out only by people who have the knowledge, skill and experience needed to avoid danger to themselves and others. It’s easy to make an electrical circuit work – it’s far harder to make the circuit work safely.
We strongly recommend that you use a registered electrician to do any electrical installation work you need. They work to the UK national safety standard and will give you a safety certificate to confirm that their work has been designed, inspected and tested in line with that standard.