You see solar PhotoVoltaic (PV) panels springing up on roofs everywhere and people keep asking me if solar electricity generation is worthwhile. The short answer is Yes. The longer answer…. that there are a list of considerations as long as your arm before you take the PV plunge. Never fear though, absolutely everything you need to know is here in this blog post!

Before reading on, please be aware this article was written in 2014 and isn't being actively updated following my leaving the renewables installation industry later that year thanks to governmental red tape. Much of the technical content remains valid, but variables such as installation costs and the Feed-in-Tariff (FiT) will have since changed with the government having announced the end of the FiT scheme entirely in 2018. The technology moves on with more efficient panels, new installation methods and battery storage options appearing as time moves on, so if you're interested in the kind of technology then speak with a reputable professional in your locale who can give you the latest advice and options.

How it works.
Those panels up on the roof convert sunlight into electricity. I won’t go into the science, there are plenty of websites that can explain how a solar panel works better than I can. Suffice to say, daylight goes in, electricity comes out. The kind of electricity a solar panel creates is DC (Direct Current), the same type of electricity as a battery supplies, and like a battery there is a positive and a negative output. DC is different to the AC (Alternating Current) pouring out of your socket outlets and isn’t compatible with the likes of your television, kettle and fridge which are wired for AC operation, so in order to use the electricity you’re producing you’ll need an inverter. The inverter sucks in the DC and converts it into AC at a frequency and voltage which matches that of the national grid. The inverter is wired back to your consumer unit where the electricity being generated is either consumed by your household gadgets, or if there’s a surplus it becomes available to the grid for your neighbours to use.

PVpanelsRetrofitted panels

Where do the batteries go?
A misconception I sometimes encounter is that the solar panels are used to charge up batteries which then provide the power. While this is the case in some off-grid applications such as on caravans and mobile homes, for a fixed installation like your average semi-detached with a permanent mains connection then there are no batteries. A grid connected PV system produces power in the daylight and has no means of storing it for use at night. It operates at peak efficiency in strong sunlight while in lower light conditions it produces less energy, and at night it does nothing at all. Battery storage options are available, but at the time of writing are expensive and not provided as part of an off-the-shelf PV package.

inverterThe inverter and associated gubbins will usually be located in the loft or somewhere out of the way

I got da power!
If enough people had Small Scale Electricity Generators (SSEG’s) then we wouldn’t need so many centralised power stations operating on dwindling fossil fuels or running on risky radiation. Most domestic PV installations have an operational limit of 3.86kW (4kWp) per phase or less in order to save on the paperwork as anything larger requires pre-installation rubber stamping from the District Network Operator (DNO), those good bods at the likes of Western Power Distribution who keep the grid humming here in Warwickshire. That said, if you have the space and the up-front dosh then it may be worth considering a larger installation. The amount you get paid for producing power drops after 4kW so installing a 4.5 or 5kW system wouldn't be worth the hassle and extra costs of the DNO paperwork as the returns would be lower, but sticking in a 8-10kW system would yield better returns which offset the lower rate and installation costs. More on that later...

A kiloWatt what??
Electrical power is measured in Watts so a kiloWatt equates to 1000 Watts. Billing refers to the amount of kiloWatts consumed over time and is recorded in kiloWatt hours (kWh). When you look at your electricity bill it will show you how much a kiloWatt hour costs - generally at the time of writing about 13p in the daytime inclusive of VAT at 5%. An electric heater rated at 1000 watts (1 kiloWatt), operating for one hour uses one kiloWatt-hour. A filament type 60 Watt light bulb operating for 100 hours uses 6 kiloWatt-hours. Some loads use a high amount of power for a short time, your kettle for example may require 3kW but is only on for a few minutes at a time. The highest load in your house is likely to be your electric shower, if you have one, rated at 7.5 to 10.5kW which is why you should keep short the naked singing time.

Give me sunshine…
A modern solar installation will provide power in daylight so you’ll still be generating on the (many) cloudy days that blight Blighty. Of course, the stronger the sunlight, the more power you can produce. You can expect maximum output on sunny days in mid summer and significantly less output when it’s cloudy or when the sun is lower in the sky as in during the winter. The further south you are the better the irradiance levels and the more you can squeeze out of the technology. It’s unfortunate, that by its nature, the best output from a PV installation is during daytime in the middle of summer when you least need it for heating and lighting. As it stands, your winter ‘leccy bill will already be much higher than your summer bill and PV will only widen the gap further, however the higher returns in the summer will help to offset the cost of those higher demands in the winter. If your electricity bill shows you consume 3000kWh per year then by installing a 3.5 - 4kW PV system you should be able to reduce your electricity bill to zero overall with the payments you receive for generating power on bright days offsetting the cost of importing electricity from your supplier during darker hours. Your PV system will always underperform in this country because, well, it ain't the Bahamas folks, so your installer should make clear at the quotation stage that any predictions regarding performance are an estimate based on the standard irradiance dataset for your corner of these isles along with your orientation to south, any shading factors and the angle of your particular roof slope dangle.

Generating kiloWatts and cash.
Solar PV comes under the Microgeneration Certification Scheme (MCS). Both the hardware (panels & mounting system) and the installer need to be MCS licenced in order for an SSEG to be eligible for Feed in Tariff (FiT) payments. Under the FiT scheme, the government guarantees to pay you for every kiloWatt hour (kWh) you produce for twenty years. A few years ago this payment was over 43p/kWh, however at the time of writing it has dropped to under 15p. That said, the price of hardware has dropped significantly and an installation today will cost a fraction of the cash which is why FiT rates have come down. There is a standardised way to calculate the returns so any company quoting you for a PV installation should be able to provide predicted annual returns which can be compared directly with any other company quoting you for a similar installation.

There are three ways a PV SSEG puts pounds into your pocket…

1. Generation FiT payment
You get paid for every kWh you generate regardless of whether you use it or not. At the time of writing the maximum FiT rate is 14.38p per kWh. In the summer my own 3kW system produces about 19kWh on a good sunny summer’s day so that’s £2.73 in the bank. Of course, non sunny days and different seasons would see much lower daily returns.

2. Export FiT payment
Additional to the payment you receive for generating each kWh, you’re also paid for each kWh you don’t consume yourself and therefore make available to the grid for your neighbours to consume. This payment at the time of writing is 4.77p.

3. Saving on imported electricity
At the time of writing you're probably paying about 13p to import each kWh from your electricity supplier. With your PV installation generating electricity, you won’t need to import so much as you’ll be creating your own. Each kWh you generate and immediately consume is a kWh you haven’t had to buy from your supplier. And remember, not only have you saved the cost of that kWh by not importing it, but the government has also paid you to generate it for yourself!

The FiT rate is tax free for small domestic (<10kW) installations. It is reviewed every three months and alters with the retail price index. The latest rates and planned changes can be found on the Ofgem website.

FiT payments can be made by your electricity supplier if they support it. Any company with more than 50000 customers has to support it, but it is discretionary for the smaller players. You can register for FiT with an alternative supplier to your energy provider so it is quite possible to be in a position where your electricity is being supplied by one company while you (effectively) sell your generated surplus to another. At the end of the day, they’re all just billing entities on the same grid so you can chop and change as you please. In fact, handling your FiT separately to your power provider can be quite handy as it saves some messing about should you be in the good habit of shopping around for the best energy deals. Good Energy seem to provide a friendly FiT service without requiring you to purchase power from them and they're who I use.

To get the most benefit out of your PV system, you want to generate and consume your energy as much as possible. This means making the most of a sunny day to run your washing machine, dryer, dishwasher, water heater and any other power gobbling appliances (i.e. things with motors and/or heating elements). You don’t want to run them all at the same time unless your SSEG is particularly powerful, but instead stagger the load throughout the day. Clever devices such as the Immersun can be installed to divert any excess power generated in the daytime to your immersion heater or any other single circuit appliance. If you do this and ditch the electric shower for a model which runs off the hot water tank then you'll be getting rid of one of the biggest power gobbling loads in your home and showering for free... at least on bright days. If you can run appliances during the day then you won’t end up paying import costs to run them at night. Even if you’re on Economy7 it is better to operate your appliances on power from your own SSEG in the daytime than to pay about 7p/kWh to import electricity to run them at two o’clock in the morning.

To apply for FiT...

Generally it's just a case of filling out a form from your chosen provider and sending them the following information:
the MCS certificate provided by your installer confirming the installation is fully MCS compliant,
proof of your identity,
proof that you own the installation,
an 'opening' reading taken from your generation meter when requested,
your Energy Performance Certificate (dated before the installation took place),
any other declarations requested.

Your chosen provider will assist you in getting registered.

Coughing up.
The best way to pay for an SSEG installation is to buy it outright, however most people don’t happen to have a few thousand quid sloshing around, or if they do then they prefer to spend it on something more exciting than a renewable energy project. Some companies will offer credit terms although you should shop around as you’ll probably get a better rate of interest on a loan from your bank. There are alternative ways to finance an installation with one popular method being the government’s Green Deal scheme. Under Green Deal you don’t need to fork out up front, instead payments for the installation are added to your electricity bill and it is paid off over time. To take advantage of this scheme you need to use a registered Green Deal installer and undergo a Green Deal Assessment beforehand. Another way is to allow a company to install the panels for free but in that scenario they own the equipment and collect the FiT payments while you just get the benefit of free electricity during the day. You see a lot of PV installations on Council owned properties because the Council own the hardware and collect the FiT payments while the tenants enjoy reduced bills. The big problem with that arrangement on your own home crops up if you come to sell the property as you will have effectively signed a 20 year lease on the roof to a PV company. Potential new owners may be put off by there being an installation they can’t collect FiT on or a roof they can’t access or alter. Any ideas they might have for a loft conversion for example may be scuppered by the equipment installed in place. If you can own the PV installation outright then it works out a lot better as you can upgrade, alter or decommission it as you wish. If you decide to move however then you won't be able to take your installation with you. FiT applies only to new PV installations and can't be claimed on 'second hand' hardware which is what you'll be deemed to have if you take the PV off one house and install on another. If you move then the new owners take over the FiT collections and you'll need to install PV on your new property if desired. As a silver lining, the fact that the new owners can collect FiT and enjoy reduced bills should add value to your property.

If making major alterations to a property or designing a new self-build then you'll likely find that it is a requirement to incorporate at least one renewable energy technology into the design in order to obtain planning permission these days. There are various renewable technologies on the market and it is worth investigating all of them to ensure you install something that suits your particular circumstances. Of course, you're not limited to one technology and can mix and match as much as your budget and green conscience allows.

If you're financing your alterations through a loan or mortgage then it may be worth factoring in the costs of a renewable technology installation even if the planning permission doesn't specifically require it. The right kind of renewables can both bring in cash and add value to your home while giving you a warm fuzzy glow about 'doing your bit' for the environment.

Payback period.
With guaranteed FiT payments for twenty years your installation will easily pay for itself. A typical 3kW installation paid for up front is likely to have a payback period of about 5-7 years at the time of writing. The panels themselves generally have a guarantee of performance of 25 years so even after the twenty year FiT payments have dried up they should still be generating free electricity for at least another five. PV installers are obliged to provide information on performance, costs and payback periods as part of their quotations and these are all calculated to industry standards to ensure all quotations are provided on a level playing field. Once the installation has covered its costs, you can kick back and watch the money roll in.

The dreaded EPC.
In order to claim the highest rate of FiT payments you'll need a suitable Energy Performance Certificate (EPC) on the building you intend to install a PV generator onto. An assessor will pay a visit and rate the building in terms of energy performance. For the high rate FiT payment you’ll need a result in band D or above. A lower result will mean you get 6.61p instead of 14.38p at the time of writing for each kWh generated which has a big impact on the cost effectiveness and financial return of the installation. The reason for this requirement is because the government doesn’t want to fork out subsidising renewable energy payments for premises which are losing energy in other ways. Easy methods to boost energy performance would be adding to your loft insulation, switching to energy saving light bulbs, installing draught proofing and fitting thermostatic radiator valves. More costly methods would be the likes of cavity wall insulation and double glazing if you don't already have such. The EPC must be dated before your PV SSEG is commissioned so you cannot use the installation of PV to boost your EPC rating for the purpose of collecting FiT. Beware of any installer who claims you can use PV to boost your EPC rating - it's you who could end up losing out. If you’re thinking of investing in a renewable technology but haven’t yet got measures in place such as adequate insulation or double glazing then you’d be better off spending your money on those kinds of upgrades first. There are government grants available to help offset the costs of these kind of measures should you need to use them.

epcPart of the EPC for my own property. While rated in band D back in February 2014, the 'potential'
column indicates I could boost performance to band B by installing Solar PV. So I did.  :-)

Planning and preparation prerequisites.
A good PV installer will help you with the following, however they will all have contractual clauses stating that these prerequisites are the homeowner’s responsibility and should be in place before work is due to commence.

1. Planning permission.
PV is generally exempt from planning requirements, however if you want to install it on a listed building, in an area of outstanding natural beauty or if structural work is required to support the installation (such as roof strengthening) then you need to go through the planning process before appointing a PV installer. If you don’t have the necessary permission in place then you may have to pay to have your shiny new PV installation removed and any damage made good. You won’t be refunded by the installer as their contract terms will state that seeking prior planning permission is your responsibility. If in doubt then you can apply to the Council for a planning exemption certificate which costs £35 with WarwickDC at the time of writing. Complete the form and provide supporting details such as photographs and diagrams of the proposed installation and if they believe it won’t come under planning regulations then you’ll get back a written opinion saying so. There are two rules which always apply to a retrofit PV installation: it cannot protrude more than 20cm from the surface of the roof and you must decommission it at the end of its working life. Even if you get a green light from the Council, it will be on the understanding that you agree to these rules. If you do find you need to submit a full plans application or if structural work is required by a builder beforehand then you should perform your due diligence with respect to these requirements before booking a date for the PV installation to take place.

2. Suitability of roof.
A good PV installer will tell you pretty quickly whether your property is suited to PV, but there are checks you can make yourself. Firstly, do you have a suitably large area of roof space facing within 90 degrees of due south? Perhaps your roof is split allowing panels on two sides such as SE and SW? Installation on directly east and west facing roofs can yield returns but the drop in efficiency must be measured against the cost of the installation. Shading can be a big problem with any PV installation - are there any buildings or trees that are likely to cast a shadow at any time of the year or, with known planned redevelopments or tree growth, in future years? Are there any obstacles on the roof such as vents, chimneys or satellite dishes? If so, can they be relocated or worked around so they won't cast a shadow over the panels? It’s a good idea to have a structural survey performed on your roof and many installers will have an in-house surveyor, otherwise you can choose to appoint your own. It’s not unusual for the rafters to require ‘doubling up’, a move that doesn’t require planning permission but gives more surface area for the roof hooks to bolt into when the frame is eventually fitted.

3. Suitability of the existing electrical installation.
How old is the electrical installation at the property? Is it due for a rewire? When was it last inspected and tested, if ever? If you have a relatively modern consumer unit with a spare way *and* it has been inspected and tested *and* the date of next inspection affixed to a label on it hasn’t expired then you *might* be good to go. If your existing consumer unit isn’t up to code or doesn’t have any spare ways then you can either have it tested/upgraded to support the PV installation or a second consumer unit may be installed. The latter option is more likely if getting one of the big boys to plumb in your PV as they’d rather not get involved with your existing electrics - it creates extra paperwork. That said, if you think your existing installation is a bit creaky, have an EICR performed on it so any issues are identified before you call in the PV installers. The electrical work will fall under Part-P of the Building Regulations so you will need proper installation and certification for that side of things.

noticeA consumer unit label showing date of last/next inspection

4. Protected species and pests.
If you have bats, bees or any protected species setting up home in your attic that may be disturbed by installation work then specialist advice will be required before you can go ahead. If you know of wasps nests or rodents lurking up there then they’ll need to be taken care of beforehand. The DC cables coming from your solar array are high voltage and high current so the last thing you want is something with whiskers gnawing through ‘em.

How are retrofit panels fixed to the roof?
Retrofitted panels are usually attached using a hook and rail mounting system. It varies for different types of roof (pantile, slate, pitched, flat, etc.), but for the most part the mounting system will consist of a hook bolted to your rafters which then protrudes from the underside of the tile. Rails are attached to the hooks and the panels are attached to the rails. From June 2014 the mounting system must be MCS012 approved to ensure it meets the standards for loading and weatherproofing. Mounting systems which are bolted through the tiles are best avoided because of the difficulty of ensuring long term weatherproofing of the protrusion.

ooksnrailsAn installation on a concrete interlocking tile roof showing the hook about
to be attached to the rafter. Afterwards the hook exits from a chamfer on the underside
of the tile. Finally the rails are attached to the hooks.

The cable entry should also be MCS012 compliant and properly weatherproof. I use a proprietary entry system designed for
such a purpose. Some installers 
save themselves a few quid by using a roof vent or they just push the cables through under
a tile. 
Doing such is not compliant with guidelines and may lead to problems for the homeowner later.

Wiring works.
One way or another, cabling from the roof has got to get back to your consumer unit (fuse box) which is usually located about as far from the roof as you can get such as in an understairs cupboard, cellar or garage. Each installation has to be assessed on its own merits, but there is a possibility of cabling being visible on either the inside or the outside of the house. This cabling may be run in conduit/trunking or clipped to the wall. If you don't like the idea of cables or conduit bolted across your new wallpaper, speak with the installer about how it can be hidden as they may spot ways of running the wiring more discretely. Airing cupboards or floor to ceiling wardrobes are a great way to sneak cables from the attic to the ceiling above the ground floor, while plans to change the carpets can provide an opportunity to gain access under floorboards. Big companies offering off-the-shelf installations are more likely to want to bang it in and move on without worrying about it looking too pretty while smaller firms may offer a neater customised installation, albeit at an increased cost to match the extra labour effort.

The frame on the roof may also need to be earthed. The requirement for earthing and the type of earth used will depend on factors such as whether there is an isolating transformer in the inverter, whether the frame can be touched by someone inside the house (via a Velux window for example), the type of electrical installation at the property, the type of panel used and specific manufacturer guidelines for the mounting system or other components. The electrician performing the installation will know about the earthing requirements, but what it means for the end user if earthing is required is additional cabling which has to get from the top of the house to the ground. Where earthing is required through the use of a separate earth rod, this cabling may follow a different path to the wiring going back to the consumer unit meaning additional cabling/conduit may be on show. This cabling would then run to an earth pit located in the ground outside the property.

pvearthAn earth pit containing a copper earth rod connected back to a PV array frame.
Earth wiring may have to follow a different route from the roof to the AC/DC cabling.

Potential additional costs and warranties.

Generally the panels themselves will have a life expectancy of 25 years and carry a manufacturers guarantee that they won’t fall below 80% efficiency within that time. The mounting system is likely to have a manufacturer guarantee of ten years. The inverter will probably have a five year manufacturer guarantee. Your installer will provide an insurance backed workmanship warranty for at least two years. Things can go wrong of course and anything that fails out of warranty will mean unexpected additional costs to put right. You may also want to consider a maintenance contract to ensure the equipment is maintained and the panels are cleaned every so often as they’ll quickly get dirty from rain/snow and peppered with bird turds. A general dirt layer and ‘dark spots’ from bird’s bottoms will reduce the overall efficiency of your SSEG over time so it pays to keep things clean.

Starting small.
Not got the dollars up front to put in a decent sized SSEG? Thinking of starting with a 1kW system and upgrading over time by adding panels as budget becomes available? Unfortunately it doesn't work like that. In order to work efficiently the inverter needs to be sized to between 80 and 100% of the rated capacity of the panels, so the inverter for your 1kW system would have to be changed if you upsized to a 2kW system and changed again if you then moved up to 3kW. The only way to increase capacity in this way is to have separate systems, say two 1kW systems working independently, but that really wouldn't be sensible for such a small SSEG and the costs of equipment/installation for two separate systems would end up being significantly more than a suitably sized single installation.

Types of PV installation.
Most PV installations are retrofit, i.e. they are bolted on to an existing roof. Although more costly, there are other options such as integrated panels which sit flush within a roof or solar tiles where the roof tiles themselves are solar collectors. These types of technology are rare and usually only employed in new builds or where there would be planning issues with a retrofit installation such as in a protected area where it may be deemed not to fit in with the surroundings. If you don't have a sloped south facing roof then flat roof or ground mounted PV solutions are also available. The more you move away from traditional pitched retrofit, the harder it will be to find an installer as many will just want to bang out off-the-shelf retrofit installations for their money and move on. As the technology matures, it's likely that integrated and special tile solutions will become more prevalent as manufacturing costs decrease in answer to an increase in demand.

The hard sell.
All proper PV installers in the UK are required to be members of the Renewable Energy Consumer Code (RECC), previously known as REAL until 2013. Under the terms of that code a sales bod attempting to sell you PV while in your own home has a window of two hours. If he or she hasn't got you to sign on the dotted line within that time then they must either leave or get your permission to stay longer by asking you to sign an 'Overstay Form'. Like with any other purchase where large sums of money are potentially involved, there are good firms and bad firms, good sales people and dodgy ones. Beware of any company who outstays their welcome, who rubbishes quotes from the competition or who tries to get you to sign there and then for a 'discounted' price, "manager's special" or other questionable incentives. Even if you have signed, you have a statutory cooling off period of 7 working days for contracts signed before 13th June 2014 or 14 working days after then where you can cancel the contract at no charge to yourself. These are your rights under the Consumer Contracts (Information, Cancellation and Additional Charges) Regulations. Personally, if I had a sales person in my home and they hadn't convinced me after two hours, I'd be asking them to sling their hook rather than authorising them to stay any longer.

Does having my own SSEG mean I can watch Loose Women during a power cut?
No, and you may find this surprising, but if there’s a power cut then your inverter will switch itself off, even when the sun is shining. It has to in order to meet the requirements of G83/2, the standard for SSEG connection to the grid. The reason for this is that if the power peeps have deliberately cut the juice so they can send their engineers up a pylon, then the last thing they want is for your SSEG or anyone else’s pumping electricity back into supposedly isolated grid cables and blowing their hard hats off! If the grid goes down, you’ll be boiling water for your tea on a gas stove or barbecue just the same as your non-PV equipped neighbours.

Do I need to change my utility meter?
Maybe. You probably won’t know for sure until you turn your new PV installation on. If you have an old mechanical spinning disc meter, then contrary to sometimes popular belief, it should not run backwards. If it does then you could be accused of falsifying meter readings and land yourself in hot water. If you have a digital meter that predates PV popularity then you need to check that it doesn’t have an anti-tamper feature which clocks electricity generated as electricity consumed or you’ll be paying your 'leccy provider for every kiloWatt hour you generate yourself. What should happen is that your meter should slow down once the PV kicks in and starts feeding your gadgets. You can test this by switching on a high load appliance on a sunny day and watch the meter as you then switch on the PV installation. If it’s a mechanical meter then you should see it slow down while a digital meter should register fewer impulses with its flashing light. A newer digital or smart meter will be clever enough to give you a direct readout of the drop in consumption and even show what you're overproducing and exporting. A good installer will be able to tell you if there is a problem with your meter, while a bad one simply won’t bother checking. Similarly, if you have an energy monitor such as those supplied by some electricity providers or made by the likes of OWL then you may need to upgrade it to a ‘PV aware’ model or it will show generated electricity as imported electricity and give false readings.

Who pays for changing the utility meter?
The utility meter is the property of the network operator and you or I are not authorised to tamper with it. If it needs changing then the first port of call would be to your electricity supplier. They are duty bound to provide an accurate means of recording electricity consumed so if you find your meter spinning backwards or counting power generated as power consumed then they must put it right. They might try to levy a charge for the change, but I would argue that them charging you for changing out their equipment when it isn’t recording an accurate representation of the electricity you are importing would be a breach of their statutory duty and you could complain to Ofgem under such circumstances. In fact, Ofgem published guidance on this subject in February 2014, in which one key paragraph reads:

“The [National Measurement Office] does not consider meters affected by on-site generation to be appropriate, as required by the Electricity Act, because of the negative impact on consumer billing and electricity settlement. Those meters that are deemed inappropriate for the purposes of the Electricity Act should be exchanged. If the supplier is aware the meter is inappropriate and does not take steps to change the meter they will not be meeting the obligations they have under the Electricity Act.”

Costs for exchange are not mentioned in the guidance but it does make it clear that the suppliers and distribution companies are responsible for ensuring their meters work correctly whether an installation has a SSEG or not. Personally I wouldn’t be willing to accept any charge if their equipment is deemed unfit for purpose, although with the big firms it may be quicker and easier to pay whatever their call centre claims is required in order to get the work done, and then write a letter to head office requesting a refund afterwards. I make no guarantees for success as most of the time communicating with a big electricity supplier is like talking to a particularly uncooperative wall.

Notifying the network operator.
You are duty bound to notify the grid operator in your area of your new SSEG within 30 days of commissioning. Western Power Distribution have a form you can fill in and send off. You will be required to provide the type verification test details for your inverter confirming its compliance with G83/2 and a circuit diagram detailing your particular installation. If they accept the submitted information then you'll get an acknowledgement letter confirming it. Your installer will take care of all this for you.

Show me the money!
Cash for kiloWatt-hours only starts being paid upon acceptance of your installation by your chosen FiT provider. They will not backdate payments to your commissioning date which will be several days prior. While you wait for your FiT application to be processed you will still benefit from the free electricity you generate during daylight hours, however you won’t be paid to generate it or to export any unused kilowattery back into the grid. Payments will probably be made quarterly but that's down to your FiT provider.

Measuring export.
Your PV installation will have a generation meter to record the amount of kWh produced, however you are unlikely to have a meter recording the amount of energy made available to the grid. Instead your export payments under the FiT scheme are ‘deemed’ meaning it is assumed that, of the energy you generate, 50% will be consumed and 50% will be exported. If you generate 100kWh in a week then you’ll receive generation payments for those 100kWh plus export payments for 50kWh regardless of whether you have used all that electricity yourself or not. Good Energy take quarterly meter readings from your generation meter and make the FiT payment to you six to eight weeks later, and other FiT operators will offer something similar. As you'll be paid to export 50% of the electricity you produce regardless of whether it is actually exported or not, if you can consume 100% of it without being unnecessarily wasteful then you'll get the maximum value from your investment in the installation.

genmeterA generation meter will clock up the kiloWatts created

CO2 savings.
A PV installation will yield a 'carbon benefit', a saving made on CO2 emissions through the green generation of electricity in place of what would have otherwise been imported from the likes of a coal burning power station on the grid. At the time of writing the figure is 0.529kg of carbon dioxide per kWh so a 3kW system can theoretically make savings in carbon emissions of nearly 1.5 tonnes per annum. Skeptics would argue that the manufacture and shipping of the PV equipment, mainly performed in the Far East using power from coal fired generators, outweigh the benefits, however over the course of the installation lifecycle there will be a substantial saving in CO2 which far exceeds what was emitted in the manufacturing and shipping process.

Do It Yourself.
Are you pretty handy with a hammer? Have you seen the websites selling PV kits? Fancy sticking it on your own roof and cutting out the middle man? Well forget it. There are multiple reasons not to go down the DIY route, but here are the big three…

1. Like any major building alteration, it needs to be compliant with the Building Regulations. If you’re a builder or a roofer by trade then you stand a chance, although you’d still need a bona-fide sparkie to provide the BS7671 electrical and Part-P paperwork. A non compliant installation risks you having to pay to remove it or put it right. A really non compliant installation which causes the roof to collapse or an electrical fire to start will likely see you fined or imprisoned. This is a big undertaking, mechanically, structurally and electrically and isn’t for the casual DIYer who assembles Ikea flat-packs at the weekend.

2. Buyer beware - the panels (and from June 2014 also the mounting system) must be MCS compliant and listed on the MCS database. The inverter must be G83/2 or G59 compliant. Non MCS panels mean no FiT payments can be claimed and a non G83/2 or G59 compliant inverter means you won't be permitted to connect it to the grid. You have to know what you’re buying and the correct way to install it. Although cutting out the expert suppliers and installers may look like a money saver on paper, get it wrong and you may end up with an installation which will never be signed off and will therefore never pay for itself.

3. In order to claim FiT payments both the equipment *and* the installer must be MCS licensed. That guy you know from down the pub who does sparkie work for cash and a pint may well offer to help you install it all, but most sparkies don’t have an MCS licence as it is hard to obtain, time consuming to maintain and expensive to keep. Unless you’re in the industry and performing a few PV installations every year to cover the costs, being MCS licenced isn’t worth the headache. If your installation doesn’t have a certificate with an installer’s magic MCS number on it then the government won’t pay you a penny and your installation won’t pull in the pounds. For most DIYers, this is the real show stopper.

The bottom line with DIY is that if you really insist on doing it yourself then you will still need to hire in the expertise to ensure the paperwork can be completed, as without it you’ll never get the FiT payments, and without them your installation will never pay its way. Your only real choice is to find a local MCS registered installer who is willing to work with you on the project, although of course their fee for doing so will be quite high as they would be taking on the liability for your SSEG. He or she would need to be appointed before you start so they can oversee the design, purchasing and installation to be sure it all meets their requirements. At the end of the day they can be audited on any of the installations on their books and they can lose their MCS licence if they sign off a job that isn’t up to code. By the time you’ve paid out for that, you probably won’t have made any significant savings so you may as well save yourself the hassle and get a proper PV installer to plumb in the whole shebang from scratch. A proper installer will also be quicker, and with FiT rates (generally) dropping slightly every three months, the sooner you can get signed off, the sooner you can see the financial returns.

I did read comments online from one DIYer who, frustrated with being unable to get his installation approved for FiT, decided he may as well pay out £600 to become MCS registered himself. I don’t know where he got that figure from, but becoming MCS registered costs significantly more than that which is why so few sparkies bother with it. You need to be a member of RECC, registered with a microgeneration competency scheme, suitably insured, pay for an MCS licence and have a quality management system in place. Besides the cost, there is significant effort required in getting a working quality management system produced and customised, and you need to be able to demonstrate the qualifications and competence in your chosen technology at an on-site assessment. All that is just for the renewable side, for the electrical side there are further accreditations, competencies and costs to consider. Even for someone like me who already works in the electrical installation field and has already been through accreditation with NAPIT for electrical work, getting MCS accredited for year one has cost around £1500 and taken several months. When you start the process, there is no guarantee you will be accepted, and unless you’re working in the trade it is highly likely you won’t ever be, however much you spend.

So, is solar PV worth it?
That’s a resounding Yes from me. Each installation has to be taken on its merits, but in my case it cost under £4000 for a 3kW system which I funded using a 5 year bank loan. With FiT payments, I can expect my return on investment period to be about 6 years and a total return of just under £12k over twenty years with a guarantee on the panels for operation over 25 years. Of course, I made savings on the labour by being able to install it myself, but even if you’re paying for a full installation it’s money in the bank. After all, unless the boffins devise a way for clean, cheap centralised mass energy production, electricity costs are only going to rise and rise while with our modern gadget-orientated world, consumption is going to do likewise.

If you believe you have the ideal roof, you’d be nuts not to do it. If you’re in the Coventry and Warwickshire area, contact me for more information. If I can’t help you directly, I know trustworthy people who can.