Photovoltaic (PV) panels convert sunlight into electricity. They have no moving parts and last for many years, making them a great source of carbon and pollution free energy.
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. Under the Smart Export Scheme you’ll be paid, on average, 5p for every kilowatt you export. Albeit on a small scale, you’ll become what the power industry calls a Small Scale Embedded Generator.
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 satellites 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 the Smart Export Guarantee 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 substantially reduce it and generate an income stream. Mounted on a south facing roof the system could be expected to produce about 3900 kWh a year giving a combined income and savings of just over £600 p.a.
Factor in battery storage and your combined income and savings leap to over £1000 p.a.
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 Smart Export Guarantee you must use a Microgeneration Certificate Scheme (MCS) installer and they must use approved products from the MCS list. We have installed a huge number of JA Solar, Canadian Solar and LG panels but also fit REC, Q Cells and Viridian. 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 G98 or G99 (depending on the output of the system). That certificate ensures the quality of the machine and qualifies your system for connection to the Grid. The machines are reliable, easy to maintain and have generous warranties.
Depending on the size or your PV system, your average electricity use, and when you are at home (using electricity) adding battery storage can dramatically increase the return on your investment.
Modern batteries are more compact and more cost effective than their lead acid ancestors. By storing unused generated electricity during the day it’s ready and waiting for you at night when you are more likely to need it. Of course when your battery is full the Smart Export Guarantee generates you an income from any excess. Our job is to ensure the correct size battery to suit your panels and usage.
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.
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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.
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.
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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.
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