The majority of PV systems are linked to the national grid which provides the perfect conduit allowing you to export electricity when you’re producing a lot and import when you’re not. There are off-grid systems that store their energy in banks of batteries and even hybrid system which switch from grid to off-grid in the event of a power cut but they’re much less common. In most domestic settings a PV system can provide much of your energy needs, but not all of it, all of the time
When you turn on a light or pop the bread down in your toaster, the device will draw current from the nearest available source. If the sun is out, the electricity will come from the panels on your roof, if not, it will come from the grid as it has always done.
If you are out and the panels are generating more power than your house is consuming, it will travel back down the mains cable and be used by others on the grid. You’ll be paid 4.5p extra for every kilowatt that you export in this way. For domestic properties your electricity supplier assumes that you will export 50% of your electricity and will pay you accordingly. Effectively, you’ll become a small scale generator in your own right – you’ll be paid for every kilowatt you generate, allowed to use it and paid to export it.
From the panels on the roof to the inverter that creates the AC current, there are hardly any moving parts. For most people the only reason they’re aware of the system is when their energy provider sends them a cheque each quarter. The life expectancy of the systems are in excess of 25 years and all panel manufacturers have performance warranties covering that period.
The array of panels, connected in series or in parallel to create the correct voltage, transmit Direct Current (DC) to an inverter. This clever bit of kit introduces a sine wave into the current which matches the 50Hz Alternating Current (AC) found in your home. The AC travels to your consumer board (via a Total Generation Meter) to be used locally or on the grid.
The first commercial photovoltaic cells were made in the 1950s and were intensively developed for use on satelites and lunar craft in the 60s and 70s. Each cell is made of a semiconductor and when light strikes the cell, some of it is absorbed. The energy of this light is transferred to the semiconductor which knocks electrons loose, allowing them to flow freely.
PV cells also have an electric field that acts to force electrons freed by light absorption to flow in a certain direction. This flow of electrons is a current, and by placing metal contacts on the top and bottom of the PV cell, it can be drawn off and used externally. This current is DC and is passed through an inverter which changes it to AC for use in your house or feeding back into the grid.
The importance of photovoltaic systems has been recognised around the world by industry and governments alike. The gradual fall in the price of PV panels combined with Feed In Tariffs make this an exciting time to invest in the future.
A 4 kWp system might not generate all the electricity your house consumes, but it will substantialy reduce it and generate a guaranteed income stream that will carry on for the next 25 years. Mounted on a south facing roof the system could be expected to produce about 3800 kWh a year giving a combined income and savings of just over £890 (based on 50% of the electricity being used and 50% being exported).
We can put a 400 panel, 100 kWp array on your factory roof or a 4 panel, 1 kWp array on your garden shed. It all depends on how much electricity you want to generate and how large your roof is. Complete our online form or request a visit and we’ll work out exactly what will fit in best with your requirements.
PV panels are interconnected assemblies of photovoltaic cells most commonly bonded to glass and in an aluminium frame. There are three main types of panels available: monocrystalline, polycrystalline and ‘thin film’. Monocrystalline cells are cut from a single cylindrical crystal of silicone and the panels are more efficient but are slightly more expensive. Polycrystalline cells are cut from an ingot of melted and recrystallised silicone and the panels are less efficient and are slightly cheaper. Thin film cells are assembled into modules by laminating them to a flexible film. Ideal where there is plenty of roof space, they are even less efficient but cheap to produce and install.
In order to qualify for the Feed In Tariff, the panels must come from the list of accredited products on the Microgeneration Certificate Scheme website. We have installed a lot of Sunrise, Panasonic and BenQ panels but also fit Canadian Solar, Perlight, Hyundai and ET Solar. Like you, we always look for the best performance combined with long term reliability.
The Direct Current (DC) in any grid-connect system must be changed to AC and it’s the inverter which handles the job. This clever bit of kit introduces a sine wave into the DC which matches the 50Hz AC found in your home and on the grid. A special requirement of the inverter is that it must automatically shut down the array in the event of a power cut in order to protect any engineers working ‘downstream’ on the grid, trying to solve the problem. This unsung hero of the PV system, frequently hidden away in the loft, gets little attention and simply gets on with its job, day after day after day.
Not featured individually on the MCS list, inverters nevertheless must carry an internationally recognised protocol known as G83/2. That certificate ensures the quality of the machine and qualifies your system for grants and FITs. The machines are reliable, easy to maintain and have generous warranties.
Whether you want to fill your childrens’ bath with hot water or generate electricity to power a small estate, we can help develop a system that is right for you. Give us a roof size, a power output or a budget and we’ll work the rest out.
Most people are rightly concerned about how their house will look with panels on the roof and if you’re interested in our quote, we’re more than happy to produce an artists impression that shows how that many panels will look. It allows you to see what see what you’re getting and to perhaps adjust the size of the array, up or down.
We’ve an enormous experience of dealing with people’s most precious asset – their home. We take care to keep you informed about what we’re doing and when we’re doing it, we tidy up around ourselves and we never forget that you will expect that everything to be as it was before we arrived (with the obvious exception of some extra hot water or electricity provided by the sun). If you’d like to talk to some previous customers, just ask, we’d be delighted to arrange it.
The Feed in Tariff depends upon your house achieving at least a level ‘D’ rating (55 points or more). If there is any doubt whether the house will achieve the necessary points, we would consider doing the EPC on your behalf before we get to contract stage – so you can be sure of where you stand.
From industrial giants to local businesses, companies are increasingly environmentally responsible. The 10kWp system we installed on the Herts Young Mariners Base in Hertford provides them with income and savings of over £4,000 a year plus sets a fantastic example to all the young people who come to the centre.
The value of the Feed in Tariff for PV installations drops as the size of the array increases however the economies of scale mean that the ‘installed kW price for large scale installations is much lower than small ones. This produces a sizeable income stream from your investment, indeed, our target is that the cost of the installation should be recovered in 10 years.
Commercial premises that are offered for sale or for let must have an Energy Performance Certificate to show to prospective tenants or purchasers. Government Buildings, Retail Units, Offices, Shops, Industrial Units and New Build Homes all have to comply. Solar systems help to improve these ratings and make buildings more attractive to new occupiers.
The Code aims to achieve a step-change in environmental performance of new UK homes. It sets out a clear timetable to reduce carbon emissions from new build housing to Zero by 2016. We can advise you on how to maximise the potential of a solar energy system on a prospective or existing development and help to achieve the current mandatory targets for reduction of carbon emissions. For more technical information on CSH, please go to www.energysavingtrust.org.uk.
Community buildings offer a unique chance to showcase your environmental concerns and offer the chance to develop a small scale generating system that pays handsome dividends. Large roofs allow multi panel arrays impossible in domestic terms which benefit from decreasing installation costs as system sizes increase. After all, you only need one set of scaffolding whether your putting up 20 panels or 200.
The roofs we covered in PV panels for Watford Boy’s Grammar School are not only a very public demonstration of their committment, they also provide them with income and savings of around £18,000 a year. Unlike houses, most of the power will be used during the day, which is precisely when it is being generated. And the savings from reducing the energy you import are greater than the income you gain by exporting.
If you’re investigating economy or environmental programs for your local community building, give us a call today. We’re already in discussions with Parish Councils, Churches and sports clubs and would be delighted to explain how solar thermal and photovoltaic systems could work for you. We can give you the costs, expected power outputs, savings and income for a variety of systems and equip you with the information you need to convince your colleagues.