Where can I install solar pv on my house?

Ideally you need a space on your property that is south facing, has no shading in summer or winter from trees, chimneys or neighbouring properties.  It doesn’t need to be the roof on your house, it could be your garage, an outbuilding or even on the ground in your garden.  However most housholds are unlikely to have a 100% ideal site, but should still consider having an installation e.g if your proposed installation is facing anywhere from due east through to due west you will still get a very good ouput.  If your panels are likely to be partially shaded at the early or late part of the day, this is acceptable.  Most importantly, you must ensure that your installer highlights these concerns and gives you a realistic expected electricity generation level based on these or other scenarios.

A good way to determine if your roof is likely to be a suitable location is to view it on the free google maps website.  Key in your postcode and you will see a satelite photo view of your property and surrounding area.  It is viewed as if you were looking at a map with north being the top of the page and south being the bottom.

There are several types of location type which can be used to mount the pv panels – see below :

Retrofit Pitched roofs

These are the most common type of installation for existing buildings. Fixings are made onto the roof which an array (name used for a group of connected solar panels) mounting system is attached to. There are a wide range of different fixing options to cater for different roof coverings and constructions.

On pitched roofs the angle of tilt of the module is generally dictated by the pitch of the roof. On very low pitch roofs it is possible to use a mounting system that raises the tilt of the panels closer to the optimum angle but additional cost and loading restrictions may rule out this option. 

Flat roofs

Where a PV array is installed on a flat roof, it is generally recommended to raise the angle of tilt of the PV panels by fixing them to a pitched mounting system. These mounting systems typically take the form of metal framed structures are usually mechanically fixed.

Where having a mounting system is not possible (usually due to planning restrictions or limitations on loadings) an alternative is to lay flexible PV laminates directly onto the roof and glue or weld them in place.

Building Integrated PV (BIPV)

A Building Integrated Photovoltaic (BIPV) system consists of integrating Solar PV modules into the building covering, such as the roof or facades. By simultaneously serving as building cladding and power generator, BIPV systems can provide savings in materials and electricity costs and add architectural interest to the building.

Integrated systems using standard sized modules or unframed modules (called PV laminates) are typically the cheapest way to install an integrated PV array. Modules or laminates are installed onto a number of mounting rails and flashings, and this combination provides a weatherproof covering to replace conventional roofing materials.

Facades

On solid facades, solar PV panels can be mounted over an existing cladding or act as cladding themselves. A significant downside to both PV facades and glazing is their cost effectiveness. The output of a vertically mounted PV panel is significantly lower than that of a pitched or even flat mounted panel. Ultimately, an array of a given size will produce less electricity per annum than one mounted on a roof.

Glazing (glass laminates)

Glass laminates (or solar glazing) can be used to replace standard glazing. Cells are sandwiched between two sheets of toughened glass, and the spacing between cells can be varied depending of requirements (i.e. more generation if spaced close together, but this will reduce the amount of light entering the building).

Whilst an area of glazing may be more suitably pitched, the bespoke nature of glass laminates typically makes them significantly more expensive than standard modules, therefore the size of PV system you get for a given capital outlay is relatively small.

Solar roof tiles

There are a number of smaller specific PV roof tiles which are available. Whereas these can offer a much better appearance, there are a couple of drawbacks. Firstly the tiles have a smaller power output, therefore more tiles are needed which increases the number of connections and secondly, they are typically more expensive.

Ground mounted systems

Ground mounted solar PV systems offer an alternative solution where a building mounted installation is not appropriate and there is enough space to accommodate an array.

Ground mounted solar PV systems consist of the PV array being fitted to a mounting structure fixed directly to the ground and the inverters installed either immediately below or within an enclosure nearby. Ground mounted solar PV systems installed in fields can be constructed in such a way that animals can graze below the mounting frames, thus allowing agricultural land use to be retained.  If you own a garden with suitable space, south facing with minimal shading, this could be a good option for you.

Tracking systems

To maximise system output, structures can be designed so the PV array will track the path of the sun during the course of the day and the angle of the sun across the seasons. These adjustable structures can be mechanised and are commonly referred to as trackers.

General requirements of a property

There are certain general requirements for any property to host solar PV panels. These are:

1. You own the freehold of the property – If you own a leasehold property, you’ll need permission from the freeholder and if you are renting the property, you’ll need written permission from the landlord. 
2. Your property is not a basement or mid-floor flat. 
3. Your property is not a listed building, nor is it in a conservation area – you don’t need planning permission for most home solar technology systems, but check first with your local planning officer, especially if your building is listed, in a conservation area or World Heritage Site.  This will require specific permissions. 
4. You have an unshaded roof, outbuilding or garden space facing between east and west through south – Ideally a solar PV system should face between south east and south west, be free of shade and should be angled at 30 to 40° for optimal performance, although PV systems can still generate a reasonable amount of energy when angled between 20 and 50° even with a small amount of shading. 
5. The roof is structurally sound – solar panels weigh approximately 12 kg each so a typical installation includinging mounting structures could weigh up to 250kg. The weight however is spread out across a large area so most roofs are capable of supporting them, but a roof survey may be a good idea.

Costs of Solar PV

• Initial cost of solar PV panels

The cost of manufacturing PV systems, in particular the cost of the panels is falling and is expected to continue to do so. The cost of PV equipment doesn’t vary much as there are only a few wholesalers in the UK, and variability in installation costs and profit margins tends to be smaller than for other technologies

DECC have used the following guide of costs per kWp installed in order to calculate the householders return on their investment (ROI).  We understand these numbers are based on 2010 pricings.  They assume a fixed cost of £1,470, plus a variable cost of £2,811/kw.  We think these costs are now lower, however the best advice is to ensure you get 3 different quotes from installers 

Example: 2kWp installation should therefore cost around £7,092.  See DECC’s website for source of costings. 

• Are there any grants available?

The main grant scheme stopped with the introduction of the feed-in tariff, but to see if any grants are available in your area search the Energy Savings Trust database.

• Will it affect the value of my property?

Installing solar PV panels will affect the value of your house as you are creating a guaranteed income for the life of the PV system. If you should sell the property the ownership of PV system also changes hands. The new owner inherits a tax free income for the remaining life of the system and benefits from the free electricity it produces. How much you value this is up to you. 

• ‘Free’ Solar PV (or ‘rent a roof’ schemes)

Several companies are currently offering consumers the opportunity to rent out their roofs in exchange for free electricity. Most of these companies will install solar panels on your roof for free, and allow you to benefit from the free electricity, but in exchange will take all the income earned from the additional electricity generated and sold to the national grid through the Feed-in Tariff scheme.

The companies benefit more from this arrangement than householders.  However, if homeowners cannot afford the initial outlay, then they can still stand to save money on their energy bills for no extra charge.

• How much electricity can a Solar PV system produce?

As a general rule, each installed kWp installed at the optimum angle can be expected to produce around 850kWh (units) of electricity per year in the UK, a 3kWp system would thus generate roughly 2,550 units year. DECC assumes in its tariff calculations that consumers use approximately 50% of the generated electricity themselves.  As a typical 3 bedroom house will use between 3000 and 4000 units of electricity per year, a 3 kWp PV system could therefore provide more than a third of this demand.

Feed in Tariff (FIT)

What is it and how it works?

Click here to see our websites description of the FIT and to see the most up to date information on tariffs. 

The FIT forms part of a Government-backed scheme that pays people who create their own electricity using renewable technology, including Solar PV.

The Feed-In Tariff guarantees a minimum payment for all electricity generated by a solar PV system (the generation Tariff), as well as an additional payment for the unused electricity produced that can be exported to the national grid (the export tariff). These payments will further boost household savings as electricity bills will be reduced by using electricity generated on-site.

 The money received for both the Generation and Export tariff doesn’t come from the government, instead it is paid by the energy suppliers. The supplier passes on the cost of the Feed-In Tariff to their electricity customers, essentially making traditional energy consumers pay for those generating their own renewable electricity.

 The tariff is available to everyone and is designed for householders who install a renewable electricity system with a capacity of 5MW or less. In addition the payments are tax-free and index-linked, and will continue for a 25 year period. The FIT is overseen by Ofgem who regulate the electricity and gas markets in Great Britain.

Do I qualify for it?

 To qualify for the full Feed-In Tariff payments you must have either had the technology installed between 15July 2009 and 31 March 2010 and transferred to the FIT before April 2010 OR have the technology installed after 1 April 2010. To qualify for the FIT you must also use an MCS accredited installer and product.

• How much can I earn?

Generation tariff

The generation tariff is a payment made by the energy supplier for each kWh of electricity your installation generates. This rate tracks inflation and will change each year, but once you join you will continue to receive the tariff for 25 years. The payment received depends on the size and type of technology you are using rather than a set rate. The good news is that the biggest payments come with solar PV technology with as much as 21p per kWh available.

Export tariff

The export tariff is another payment for every kWh of electricity you generate but don’t use and then export to the national grid. The payment has a set price of 3.1p per kWh. The tariff has been designed as an extra incentive to encourage people that they will still receive money for any surplus electricity they generate.

 According to the Government, these tariffs should cover the initial cost of the installation of the technology with a return of up to eight per cent over a 25 year period. You can calculate the potential return of a PV systems Solar Guide’s Solar PV Feed-In Tariff Calculator.

• How is my electricity generation measured?

 As the tariff payments are based on kWh’s produced and exported, the energy generated needs to be measured. A meter needs to be installed to measure the three energy flows; generation, import and export.

You will already have an import meter which is used to calculate your energy bills. Some of these are capable of measuring export too, but this will need to be investigated. A generation meter will be provided with whichever MCS certified product you choose to have installed.

However, it’s worth remembering that Smart Meters are soon to become widely available and will be able to cope will all of your meter reading requirements.

• Future of FIT

The Government has vowed to regularly review the FIT scheme to ensure that it is working accordingly. The first review was due in 2012, however on 7^th February Chris Huhne launched a fast track review of the FIT following evidence suggesting that solar farms were hovering up money intended for households and small businesses. The initial changes to the scheme only effect installations over 50kW, which are unlikely to be household installations.

Index linked

In addition, the FIT payments are index-linked (to the RPI) meaning that earnings from the FIT will keep on top of inflation.

• How do I apply for FIT payments?

In order to claim for FIT payments from a Utility Service Provider (USP), the Microgeneration Certification Scheme (MCS) accreditation number of the installer needs to be known. An MCS accredited product must also be used.

It is also a good idea to make sure the USP support the FITS. Although the majority of the UK’s USP’s do support the FIT scheme it is important to know before paying out. Once the installation is complete you will receive a pack containing all of the relevant information about your system, including an MCS and FIT eligibility certificate from your installer when the work is finished. The supplier will then cross-reference your installation with the central FIT database and cleared payments will begin to be paid to you at intervals decided between you and the supplier. In most cases the FITS payment is made by personal cheque to the person named on the household utility bill every quarter.

Choosing an installer

 It is important to choose a reliable and trustworthy installer, to help customers make an informed decision a certification scheme has been introduced for both installers and products on the market, known as the Microgeneration Certification Scheme (MCS). In the process of becoming MCS accredited, installers wishing to sell or lease renewable energy products must sign up to a consumer code such as the REAL assurance scheme.

See the REA’s website for a list of installers and the REAL website for further details about the consumer code.