Commonly asked questions about Solar Energy Systems
What is a Solar Photovoltaic (PV) System?
A Solar Photovoltaic System utilises the energy from the sun to generate electricity. The electricity generated from the PV panels can be used to power electrical requirements within your house, office or factory.
How does Solar Energy work?
Solar Energy utilises the daylight generated by the sun to produce electricity within photovoltaic cells located on roof mounted panels or in other locations which have full daylight access. The energy is routed from the panels via cables to a DC inverter. This inverter converts the energy into an AC supply that you receive from your electricity supply authority and then is either utilised within your building or premises or can be sold back to your electricity supply authority.
How do PV systems help our environment?
PV systems are a renewable energy source that do not burn fossil fuels to generate electricity and do not leave a carbon footprint as it creates no carbon dioxide during its general operation. For every kw of electrical energy that is generated by a fossil fuel, about .54kg of CO2 is released into the atmosphere and the average person uses around 600-800kwh of energy every month. PV systems emit no pollutants, create no waste and use no fuel which is a very green energy supply.
A 2.4kWp system can generate approximately 2500 kWh per year, equal to more than 1360 kgs of CO2 emissions saved.
What is the life expectancy of Photovoltaic Modules?
As the solar PV panels are a fixed item with no moving parts, all modules have a lifespan of over 25 years but generally will last in excess of this period of time. Playfords supply only high quality panels from manufacturers that have a long history of proven performance. Unfortunately, there are many new products being introduced to the market with < 3 years of proven technology.
How many modules do you need to produce 1 kw of electricity?
Generally most modules or panels are rated around 200-250w each in bright sunlight. This is generally presented as 200-250 kWp with each module approximately 1650cm x 1000cm. Therefore, to achieve 1kw of solar power you would need approximately 4-5 modules or panels, which would cover an area of approximately 8sq. metres. Larger systems >1kW will increase in size accordingly.
How does the electricity produced by the solar PV system connect to the electrical system in the house or office?
The solar panels convert the solar energy into DC (direct current) electricity. The energy is routed from the panels via cables to a DC inverter. The inverter turns DC electricity into 230-volt (AC or alternating current) electricity. The AC power enters the utility panel on the property where the electricity is distributed to appliances and lights throughout the building.
What happens to electricity produced by solar modules if it is in excess of the demands of the house or office at that time?
Energy can be sold back to the electricity supply authority if it is a grid connected system. The current reimbursement for energy exported back to the grid is £0.045 per kWh.
Alternatively, if it is an off the grid system, an arrangement of batteries could be utilised to store the electricity. This is generally not utilised for domestic installations due to the additional financial investment and size of the batteries, but could be an option for commercial applications.
How do I know how much electricity is being generated by the solar PV panels?
There are various models of meters and data monitors that can be used to record and monitor your system. You will require an additional electricity meter to measure the electricity that your system is generating (known as a total generation meter), and also to measure how much is being fed back into the electricity grid (commonly known as an export meter or feed-in, feed-out meter)
What are Feed-in-Tariffs (FITs)?
Feed-in Tariffs (FITs) are financial incentives (payments) to anyone who owns a Renewable Energy system. Feed-in-Tariffs have been widely used around the world to encourage investment in renewable energy and first became available in Great Britain in April 2010.
In brief, the Feed-in-Tariffs are designed to provide you with a quarterly income to offset your capital investment in the equipment and installation.
The FIT scheme covers the following electricity-generating technologies, up to an installation size of 5MW (mega watts):
- Solar electricity (PV) (roof mounted or stand-alone)
- Wind turbine (building mounted or free standing)
- Micro combined heat and power (micro CHP) (limited to a pilot at this stage)
Current Feed-in-Tariffs for Solar Energy installations, which are registered under the scheme between 1 August - 31 October 2012, will benefit from the following:
All generation and export tariffs will be linked to the Retail Price Index (RPI) which ensures that each year they follow the rate of inflation.
You can benefit from the Feed-in-Tariff in 3 ways!
- Generation tariff – Receive up to 16p/kWhr, depending on the type and size of the system used to generate renewable energy (see schedule below)
- Export tariff - you can receive an additional 4.5 p/kWh from your energy supplier for each unit you export back to the electricity grid.
- Energy bill savings – save on your electricity bills by generating electricity to power your appliances. The amount you save will vary depending how much of the electricity you use on site.
Example of how the Feed-in Tariff works for commercial customers:
All calculations are based upon existing Feed-in Tariffs (i.e. 13.5p per kWp for systems 10-50 kWp
1. Feed in Tariff is index linked to RPI. Assumed 3% inflation p.a.
2. Electricity costs start @ £0.12p Year 1 (average) and increasing 3% inflation p.a.
3. Export revenue assumes an Export Meter is installed @ £300 (Yr 1-5) and £250 (Yr 5-25)
Will the PV installation continue to work in the event of a power cut?
If it is grid connected it will not, as it will provide problems feeding back into the grid in the event of power outage, thus causing dangerous levels of electrical potential in the grid through back-feeding of supplies. Grid connector systems have an automatic cut-off so that it monitors the mains electrical supply. If that fails, the PV systems will also be isolated. If it is an off the grid system, then yes, electricity will still be available to the house or office premises during period of power cuts.
What about winter, when there is very little sunlight?
Solar PV panels produce electricity at their peak on long sunny summer days. However, they will continue to produce electricity even in the winter months when the sun is lower in the sky or even in overcast weather as long as they are receiving an element of daylight. Obviously, in these situations of reduced sunshine, the level of electricity produced by the solar panels is equally reduced.
How long does an installation take?
Generally these can be completed in approximately 1-2 days for domestic installations and 5-10 days for commercial installations. There will be an element where some scaffolding will be required to gain access to the roof to install the roof fixings to hold the solar panels and cables routed from the roof to the electricity incoming position, consumer unit or mains distribution panel.
Can solar PV panels be installed on any roof?
The ideal location for solar PV panels is from a south-facing elevation. Modules on south-east or south-west facing installations will produce a slightly reduced amount of power.
Will Planning Permission be required?
Generally no, however it is worth checking. If you live in an area of conservation or within a listed building you may just need to check with your Local Authority before purchasing and installing a solar PV system. A flat roof installation will always require planning due to structural stresses that may be applied to the roof from wind pressures etc.
How much does a solar PV system cost?
Residential property owners are currently paying approximately £1800 -2000 per kWp. (i.e 4.0 kWp = £7000-8000)
Commercial property owners benefit from size and scale - but can vary dependent upon type of building and roof
call for estimate: 01954 251 966
Do the solar PV panels require regular maintenance?
Solar PV panels require little maintenance. Installed on roofs they are generally kept clean by rain. However, you must ensure that they are not obscured by shade, i.e. trees which continue to grow which then cast shadows over the panels. In accordance with general electrical practice, all electrical systems need a test and inspection every 10 years which would cover the electrical integrity of the system and house/premises. Shorter time periods may be required for commercial and industrial clients with regard to test and inspection regimes.
Is the system MCS Approved?
Yes! Playfords is an MCS Approved Installer and all systems are compliant with the Government feed-in tariff scheme. Learn more @ www.microgenerationcertification.org.uk
What happens if I move home?
Ownership of the technology is linked to the site and, therefore, in the case where a building or home ownership changes, the ownership of the technology would also transfer to the new owner.
I rent my property. If my landlord installs an electricity generating technology, who would receive the FITs?
It will be up to landlords and tenants of domestic or commercial property to come to an arrangement about the receipt of payments and on-site electricity use benefits.
Will I be eligible to receive the tariff if I move into a home that already has an electricity generating technology?
FIT eligibility remains with the installation, even if the ownership of the home or generating technology changes. Therefore the technology must have been eligible before you move in, even if it is not registered yet.
The Energy Regulator, Ofgem, has been appointed as the administrator of the FIT scheme www.ofgem.gov.uk. The scheme administrator is responsible for overseeing the whole scheme and maintaining the register of eligible systems and the tariffs paid to them. Because the tariffs are paid through all the electricity suppliers, it is necessary to maintain a central register so the details are not affected when people switch suppliers.
Also refer to the government's Energy Saving Trust for any updates to the scheme that may affect your circumstances: www.energysavingtrust.org.uk
All installations must be completed by a qualified agent. All agents must have an MCS certificate, approved by the standards set out within the Microgeneration Certification Scheme: www.microgenerationcertification.org