Specialists in Solar Panel installation

  Why Solar?

Apart from the facts of saving and making money from a solar installation, there are many general advantages, such as:

  • Only daylight is needed to create energy - not sunshine.
  • Clean energy - no greenhouse gases, no air or water pollution, no by-products that can create elimination problems, and no environmental damage in producing the energy.
  • Renewable energy - unlike fossil fuels, the sun is an unlimited supply of energy.
  • Silent - a noiseless operation.
  • Robust - no moving parts means less can go wrong.
  • Low maintenance - again partly due to having no moving parts.
  • Long lived - the lifetime of a solar module is estimated at 40-60 years.
  • Ensures better use of conventional grid electricity.
  • Reduces our energy dependence.
  • Economical - cost-effective solution to local energy production.
  • Power in inaccessible areas - where there needs to be less dependence on the utility to provide power for homes or other buildings.
  Will It Work For My House?

Every kWh of electricity generated and used in your property makes you money, and an additional income is earned for every kWh of electricity you generate and sell back to the grid. This income is guaranteed for 25 years (for Solar PV systems), tax-free and index-linked to RPI.

Every installation and energy usage is different, but it is possible to give some approximate figures to illustrate the cost savings. By generating its own solar electricity, an average three-bedroom home will earn around £900 per year in FiT payments, together with a likely reduction of £140 from the household electricity bill.

At night, any electricity required is bought as usual from your utility company.

In order to maximize your use of solar technology and to reduce electricity bills, you can run your electrical appliances, such as a washing machine and dishwasher, during daylight hours.The Energy Saving Trust calculates that the average 3 bedroom house consumes 3,300 units of electricity (kWh) per year. They assume that cooking and heating do not use electricity. To make a comparison to solar, you can find the number of units that you use from your last few bills.

It is further recommended that you ensure your home is as energy efficient as possible. Where possible, this can include installing loft insulation, solid or cavity wall insulation, double glazing, an efficient boiler, and energy saving light bulbs. Not leaving electrical equipment on standby will also reduce your electricity consumption, making for a more efficient use of your PV system.

In installing the system, the wiring can often be fed through existing cable routes, minimizing the disturbance to your home's fittings and decor.


It is estimated that an average system takes about 8-10 years to pay for itself, after which it will make money for its owner for the rest of its life; that is 15 years of profit, or longer given that panels should last longer than their 25 year guarantee. On average, a system costing £10,000 would give a return on investment of about 9% per year. First Greentech can give you an estimate for your property and chosen system. We offer a product warranty of 25 years for the PV modules, as well as a performance guarantee (typically 80% output after 25 years). The inverter guarantee depends on the type installed, but is usually for 5-10 years, though some can now be guaranteed for up to 25 years.

The more that you use the system, the greater the saving, but for a specific property this will depend on how much you pay for electricity at the moment and how much electricity prices increase in the future.

The average home installation is a 2.5 kWp system. The typical installation cost will be between £4,500-£6,000 per kWp, but will vary according to ease of access to the roof and the product chosen.

At First Greentech, we give you a breakdown of costs, so that you as the customer know exactly what is being paid for. An initial estimate will include:

  • Survey and PV system design.
  • Cost of equipment and installation,including all solar panels and associated electrical units. We do not give quotations over the phone. We need to see your property and to tailor the solution to your property.
  • Connecting the solar panel system to the grid.
  • Correspondence with DNO (distribution organisation operator) to register the system.

VAT - One further advantage is that the VAT charged for both the system parts and installation, is only rated at 5%.

Aftercare Service - This is offered as a maintenance contract for roof mounted PV modules, in order to clean the panels, from for example, general dust and grime, bird droppings, etc.

Quotations - We do not give quotations over the phone. We need to see your property in order to tailor the solution to your requirements.

  Feed-in Tariff (FiT)

This is a pay-back legislation encouraging the installation of solar, to achieve grid parity. FiT returns come in 3 forms.

  • Revenue for generating kWh, whether or not any of the energy is consumed.
  • Revenue for exporting kWh to the mains grid.
  • Savings from using free solar electricity rather than mains electricity.

Furthermore the generation tariff is Index-Linked to RPI and guaranteed for 25 years. (Payment rates for new entrants are to be reviewed every 5 years). This makes Solar PV one of the best investments for your money, both in terms of return and safety. These price subsidies are a key part of the reason that solar energy's time has arrived. Approximately 30%-50% of the electricity produced by a typical domestic PV installation is used by the home owner.

A final incentive is that the Inland Revenue has ruled that the VAT charged on both parts and installation are to be rated at 5% when installed by a VAT registered installer, such as First Greentech.

PV Scale Tariffs for New Installations
[Rising with inflation annually]
  Year 1 Year 2 Year 3  
≤ 4kW (new build)   36.1 36.1 33  
≤ 4kW (retrofit)   41.3 41.3 37.8  
> 4-10kW   36.1 36.1 33  
> 10-100kW   31.4 31.4 28.7  
> 100kW-5MW   29.3 29.3 26.8  
Standalone system   29.3 29.3 26.8  

Figure 3: FiT Payment Rates paid per unit of electricity generated

Any electricity generated and not used is exported back to the national grid and you will receive an ADDITIONAL 3p (per kWh) for each of these units.

Cashback Calculator
The following Cashback Calculator will give you an idea of how much you could earn and save through solar electricity panels, (as well as other forms of renewable energies) using the FiT scheme.

Recent Subsidy Increases
The UK Government increases Feed-in Tariff rates in line with the retail price index. As of 1st April 2011 the Feed-in Tariff for Solar PV systems will increase in line with inflation (4.8% increase).

PV Scale Scale of previous
Feed-in Tariff (pence/kWh)
Feed-in Tariff (pence/kWh)
≤ 4kW (new build)   36.1 37.8
≤ 4kW (retrofit)   41.3 43.3
> 4-10kW   36.1 37.8
> 10-100kW   31.4 32.9
> 100kW-5MW   29.3 30.7
Standalone system   29.3 30.7

Figure 4: Adjusted Feed-in Tariff rates, 1st April 2011

For more information please visit www.ofgem.gov.uk

Process for Claiming FiT
Tariffs are collected against the standard metre that comes with the system. Simply submit the reading to the utility company, which then makes the FiT payments quarterly.

As installers, we provide an MCS certificate for systems that are less than 50kW in size. For systems of greater than 50kW, Ofgem gives a ROO-FIT accreditation number. The utility company needs to register your system and verify generation and export metres. FiT revenue is paid by the utility company to the customer per kWh.

The Renewable Heat Incentive (RHI)
This is a government financial support scheme for renewable heat announced on 10 March 2011, designed to revolutionise the way that heat is generated and used in buildings and homes, said to be the first of its kind in the world.

The RHI policy document details the arrangements for this scheme, which will provide long-term financial support to renewable heat installations to encourage the uptake of renewable heat. The Department of Energy and Climate Change are aiming for the regulations which underpin this scheme to be approved by Parliament in summer 2011 and the scheme will be introduced shortly thereafter.

RHI will incentivize consumers to generate their own heat energy, in a similar way to the FiTs for consumers generating their own electricity. Full details on RHI are to be published, but further information can be found on the Department for Energy and Climate Change website.

  Main Components of a PV System
  • Photovoltaic Modules (that is, Solar Panels)
  • Inverter
  • Solar Power Meter
  • House Consumption Meter
  • Mounting System
  • Wiring

This is perhaps the most basic item to get right. Any shading on even a single module will affect the whole array, because all the modules are connected to each other. So trees, chimneys, TV aerials and other common causes of shading need to be accounted for. Whilst a little shading can be tolerated early or late in the day, the installed system should not suffer any shading during the main daylight hours.

  Limited Roof Space

This can be dealt with by using higher efficiency panels. Sanyo panels are the highest efficiency; they have a layer of amorphous silicon and a layer of crystalline silicon in the same panel. Sunpower panels are another possibility.

  Orientation and Pitch

For optimum performance, the roof should face south and be at a pitched angle of 30-40 degrees to the horizontal. (The optimum inclination varies with latitude, but is tilted from the horizontal to an angle that is the latitude of the site minus approximately 10-15 degrees. In the UK this varies from about 30 degrees in the South to almost 40 degrees in Northern Scotland). However, east and west facing roofs can provide up to 85% of this optimal performance. We will not install on north-facing roofs.

As company policy, we always attempt to find the most cost-effective solution. Another company policy is that the panels are mounted on south-facing facades (or anywhere from East to West through South). We do not install PV panels on north-facing areas; this only allows the PV panels to absorb light for a minimum of daylight hours. For increased efficiency, bright sunshine in cold temperatures is best.


Dust and dirt are usually washed off by rain, especially if the orientation is at least 15 degrees. In extreme cases dust may cause a power reduction of about 10%. Cleaning the modules can be done using either water from a hose, or soapy water and a non-abrasive brush.

The manufacturers of all of the panels that we use give a warranty of 20-25 years, and the installation comes with a 5 year warranty, so in the unlikely event that an issue arises, we can return to ensure that everything is working properly.

There is likely to be an interim cost in that the inverter will probably need replacing earlier than the 25 year guaranteed lifetime of the panels. We only use inverters from the top manufacturers.

  Planning Permission

Most domestic solar installations do not require planning permission, coming under the permitted development rights heading. The exceptions are listed buildings, buildings in conservation areas and world heritage sites.

The Energy Saving Trust has more information on planning permission:

In blocks of flats, whether in a converted property or purpose-built, planning is required from the local council. Some useful basic information can be found on the following website:


The type of boiler you have is not an issue when choosing a photovoltaic system.


PV panels are tested against ballbearings to withstand a hailstorm.

  Power Cuts

In case of a power cut, your solar system switches off automatically. This prevents electricity leakage into the national grid, to which the system is attached, as well as protecting people working to restore the power supply.

  Roof Space

As a rough guide, a roof area of approximately 20 square metres would provide about half of a typical household's electricity requirements.

  Connecting to the Grid

Any electrical grid connection requires approval from the distribution organisation operator (DNO), responsible for maintaining the local electricity grids. After the system is installed, we will assist the customer with the registration process, which involves sending copies of the commissioning form, the inverter certificate and the electrical design to the local DNO.

Distribution Network Operator (DNO) Companies include:

  • e.on
  • UK Power Networks
  • Western Power Distribution
  • SP Energy Networks
  • CE Electric UK
  • Electricity Northwest
  • SP Energy Networks
  • Scottish and Southern Energy
  • Northern Ireland Electricity

There are also some independent DNOs, such as Fulcrum and Inexus.

  Estimating Likely Output from a PV System

First find the irradiation level in your locality.

The map shows the annual irradiation levels for optimum angled PV panels, that is at 30% to the horizontal. Two scales are shown. The top one gives the irradiation over the country (kWp per square metre) and the lower one a factor which can be used to convert the module/system power to actual units of electricity (kWh/kWp) based on a performance ratio of 75%.

For example a 2 kWp PV system at a location having say 800 kWh/kWp, say near Derby, will produce 2 x 800 kWh of electricity per annum. The performance ratio of 75% is an estimated efficiency for a typical roof installation, taking account of the fact that most roofs will not be at the optimum angle and will not be perfectly south facing.

  How Solar Panels Work

The process of converting sand into solar energy can be summarized as:

           Polysilicon → Ingot → Wafer → SolarCell → Solar Module

Silicon from sand or quartz is melted and cooled over a 24 hour period. This produces an ingot which is sliced into fine wafers (160 microns thick). The thickness is further decreased. To reduce the shine on the surface which would reflect too much light, it is dipped into acid. This anti-reflective coating is also designed to maximise the amount of light reaching the solar cells. Furthermore, the front glass is slightly granular and so matt rather than mirrored. Silver lines are then painted on top of the cell to trap the electrical current created. The 72 cells in each module are joined together by copper strips to laminate them. The kevlar/polyester back makes the module water-tight and is the secret to the 25 year warranty. The silicon is required to have a purity of 99.99999%.

A solar panel (or module) is made up of solar cells, which are solid state devices that convert the energy of daylight directly into electricity by the photovoltaic effect. Solar power relies on the intensity of the light, not sunlight directly. Because they only require daylight rather than direct sunlight to produce electricity, solar panels still produce energy on cloudy, overcast or rainy days. According to the BPVA (British Photovoltaic Association), partially cloudy conditions can actually increase the output from a PV system. The weakest cell in a module determines the module output. Modules are checked after their manufacture and before shipping, and again by the installer before installation, greatly reducing the possibility of a faulty panel. Furthermore PV modules typically have a 5 year defects guarantee. Module efficiency is a function of module output, length and width.

The electricity that is produced by the PV system is first used to power any electrical appliances in the home. Any unused electricity is automatically directed into the utility grid, and money is paid for this fed electricity. It is estimated that panel performance decreases by less than 1% per annum; they should still be 60% efficient 50 years after installation.

  Types of Solar Panels

Multicrystalline modules are square in shape. These are produced from a very pure, molten silicon that is cast. Typically they have a blue colour, which comes from the application of an anti-reflective layer. The thickness of this layer determines the colour.

In comparison, Monocrystalline cells are more efficient but have round corners, so much of that efficiency is lost. One crystal ingot is cut into slices between 0.2-0.3mm thick, which then form the basis of a module. This type of panel offers the best return on investment.

Amorphous silicon, sometimes known as thin-film technology, is made from non-crystalline silicon. The thin layer of semi-conducting material means that less raw material is used in producing this type of PV cell in comparison to the other two types.

Thin film technology comes in four main types, amorphous silicon, cadmium telluride, copper indium gallium (di)selenide (CIGS), and dye-sensitized and other organic solar cells. This type of cell arguably degrades more rapidly than the other types of modules. It is better in hot weather, so we doubt it will become popular in the UK, but is rather better suited to desert climates where both large areas and extreme sunshine are present. Like-for-like, the efficiency of a thin-film module is 7-9% compared to PV modules that we recommend, whose efficiency lie in the range 16-21% (a ratio of kWh to kWp).

  How Solar PV (Electric) Works

Solar photovoltaic (PV) systems convert daylight into electricity via solar panels which use a thin layer of semiconducting material, usually silicon, enclosed between layers of glass or plastic. The incident light dislodges electrons from the material, which then flow to produce direct current (DC) electricity. The direct current passes through wiring to an inverter, which converts it to alternating current (AC), so that it can be connected to a property's main electricity distribution board.

Unlike fossil fuels, no carbon dioxide is emitted when using solar panels. The sun provides an abundant, free source of clean energy.

  How Solar Thermal (Hot Water) Works

A solar collector converts light into heat energy, which then heats up a fluid circulating through the solar collector. The fluid flows through the heat exchange coil at the bottom of the hot water cylinder, thereby heating up the water. The heated water rises to the top of the cylinder and is ready for use through the taps. In the meantime, the fluid is pumped to the roof for reheating. When solar is not available, the boiler is the source of back-up heat.

Ofgem estimates that 70% of a homes gas costs go on heating and 30% on hot water.

A highly experienced solar water heating expert calculated that the reduction in the overall gas bill would be closer to 10% - a saving of about £55 a year at current gas prices.

A solar water heating system includes pipe work, a thermostat and hot water cylinder, used for domestic hot water as well as swimming pool heating. The location of installation is less sensitive than is the case with PV.

Most existing hot water systems can be supplemented with solar water heating panels. Usually however there is a need to add an additional cylinder for pre-heated water, or exchange the existing cylinder for one with a twin coil.

Solar water heating systems supply low pressure warm water, and whilst some new combi boilers accept pre-heated water, usually they are only designed to take cold mains pressure water.

The typical cost of a solar water heating panel is between £3,000 and £5,000, which would save between £50 and £85 a year on water heating costs, providing 40-70% of annual hot water needs. The largest savings are to be made if you have an electric heating system.

Roughly one square metre of collector area per person in the household is required. Each metre of panel area will need between 30 and 60 litres of water tank volume.

A less efficient collector (such as flat plate solar water heating panels) needs to cover a larger area than a more efficient collector (such as evacuated tubes). The owner selects system components (such as a hot water cylinder, controls and pipe work) and chooses the location for panels considering shade, pipe runs, roof pitch and future access.

The Low Carbon Buildings Programme, the government's grant programme for renewable energy systems which has been extended to run until April 2011, offer grants of up to £400 or 30% of the cost of the solar water heating system (whichever is lower).

The equivalent for solar thermal, to FiT for Solar PV, is the RHI under which a typical household with a solar thermal system could save around £200-£300 per year.

  Payback and End of Life

It takes less than 3 years for a PV system to become energy and carbon neutral, that is to be supplying back more energy than that used in its manufacture. This is decreasing with improvements in technology, and is expected to be under 2 years soon. For thin film technology, it is already less than 1 year. http://www.nrel.gov/docs/fy04osti/35489.pdf.

The PV Cycle organisation was founded in July 2007 to implement the photovoltaic industry's commitment to set up a voluntary take back and recycling programme for end-of-life-modules and to take responsibility for PV modules throughout their entire value chain.

For more information see www.pvcycle.org

Under this scheme the modules can be taken to a site to be stored and later collected for recycling. This dispenses with having to obey the WEEE Directive. There are plans to build 10 more sites in the UK in addition to the 2 already in use. Over the next year there will be up to 150 more sites designated throughout Europe.

  Council Tax

Council tax is based on 1991 rateable values, and at present the value of panels is not taken into account. It is possible that in future council tax will be replaced by an assessment based on the Energy Performance Certificate, in which case having Solar PV panels would reduce your tax bill.

  Energy Performance Certificates

Energy Performance Certificates (EPCs) give information on how to make your home more energy efficient and reduce carbon dioxide emissions. All homes bought, sold or rented require an EPC. Installing solar panels is likely to increase a home's energy efficiency rating. For more information see http://agenergyuk.com.


The solar radiation that hits the panel ages the solar cells in the module and produces slightly less energy each year. There are many factors that affect degradation, and there is no consensus as to how this should be measured for the annual reduced output. Some maintain that the figure is 0.2% per annum whilst others say that it is 0.8%. A higher value makes for a more conservative returns estimate and a lower yield estimate.

When installing the system, the wiring can often be fed through existing cable routes, minimizing the disturbance to your home's fittings and decor
This income is guaranteed for 25 years (for Solar PV systems), tax-free and index-linked to RPI