Solar Questions and Answers
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Solar Questions and Answers

Solar Shop - Specialising in practical Solar Product

The idea of solar PV raises many questions in the mind of the consumer, and here at SolarShop, we aim to provide all the answers you need before you commit to purchasing a system. Below are the most frequently asked questions - if you have any further questions then please do not hesitate to contact us.
Question: Is there any difference between a Kilowatt (kW) and a Kilowatt hour (kWh)?
Yes there is. A Kilowatt is a thousand watts - with watts being the S.I. unit for power. A kWh is the amount of energy converted by the solar panel if work is done at an average rate of one thousand watts for one hour.
Question: In relation to this, what is a kWp?
KWp stands for peak power. This value specifies the output power achieved by a Solar module under set Standard Test Conditions. Solar radiation of 1,000 watts per square meter is used to define standard conditions. Peak power is also referred to as "nominal power" by most manufacturers.
Question: Can solar panelling create energy?
Solar panels convert energy from the Sun into electricity, as opposed to actually creating new energy.
Question: What exactly is PV?
PV is an abbreviation of 'Photovoltaics'. This word was first used at the end of the 19th century and can be split into two components; the first being 'photo' which means light, and the second being 'volt' which is a unit used to measure electrical voltage. 'Photovoltaics' literally means electricity from light, which is exactly how the process works - converting light into electricity.
Question: What makes up a photovoltaic system?
A PV system consists of numerous components, some more obvious than others. PV Paneling is a necessity. An inverter is also required to convert direct current (DC) from the panels to an alternating current (AC) for use in the home. In addition, all of the necessary wiring tools and mounting framework are needed.
Question: How does the PV System work?
In short, sunlight hits the photovoltaic cells and gets converted into clean, usable electricity. The inverter changes the electricity from Direct Current (DC Current) to Alternating Current (AC Current) that can be used in the home. If excess electricity is created it gets sold back to the Grid, while if there is not enough light to draw upon such as at night time, electricity is taken from the Grid in the regular way.
Question: What are the different types of Solar power technology?

There are four main different types of solar power technology.

Solar PV system: Solar PV panels convert the Sun's light into electricity.

CSP (Concentrating Solar Power) system: Troughs or mirror panels concentrate the light of the sun to heat an element. This heat can then be used in the same way as heat is used in traditional power stations to create electricity.

Solar Water heating systems: Water is either heated directly by the Sun, or a liquid with a higher specific heat capacity is heated and, in turn, used to heat the water.

Solar walls (transpired solar collectors): These use solar energy to preheat ventilation for buildings.

Question: Do solar PV panels work in Winter when it's cold?

The short answer to this question is yes. The panels do not require heat; it is light that makes them generate electricity. Even when overcast, your panels will produce electricity, with the only thing lessening the amount of energy produced being the shorter days.
Question: In the case of a power cut, what happens to my solar PV system?
As the system is attached to the National Grid your system will be automatically switched off in the case of a power cut. This is a safety precaution, so not to expose those working on resolving the problem to danger of electrocution.
Question: Does my solar PV installation require batteries?
Batteries are not required as your installation is wired up to the National Grid. The only case in which batteries would be deemed necessary is if the system is fully independent from the Grid, and consequently needed to store electricity for when panels would not produce electricity such as during the night. Batteries are also an extremely expensive addition to a Solar PV system, and thus are only fitted on request.
Question: How much energy do I require?
The Energy Saving Trust calculates that the average three bedroom house uses 3,300kWh a year (assuming cooking etc. are on a non electricity based supply). To see your specific requirements though, it is recommended to check your own past bills which will give your figure.
Question: What happens if I produce more energy than is required?
Any excess energy will be sold back to the National Grid and be available for use in other homes. We will help you set this up with your energy provider after your Solar PV system is installed.
Question: What does the term 'energy conversion efficiency' mean?
This is the amount of energy produced in relation to the amount of energy consumed. Even though Photovoltaic technology has come on leaps and bounds over the last few years, even in its current state it only captures between 7-17% of the sun's energy, but is improving all the time. Indeed, some experimental PV cells are now getting to the point where they can use 40% of the light's energy and change it into electricity. In comparison, fossil fuels usually generate power at roughly 28% efficiency.
Question: What reasons are there to implement a solar PV system?

Photovoltaic systems are growing in popularity all the time and for good reason. They present a green, sustainable and cheap alternative to fossil-fueled electricity. Although the initial outlay is large they pay for themselves in a relatively short time.

Furthermore, they are a durable and reliable system of energy production, that requires little maintenance and after 15 years show very few signs of wear and tear. They create no pollution, thus helping the environment against the ever growing problem of global warming, and can easily be expanded if required.

Question: Are there any reasons not to switch to solar energy?
The substantial initial outlay that is required to install a solar PV system can be off-putting. However, this is negated in the long term by the Feed In Tariff, savings made on energy bills and Renewable Obligation Credits, all of which make the transition worthwhile at present.
Question; Why not wind power?
While wind power is also an excellent source of energy, in an urban landscape it is not necessarily a viable option. Wind speeds of 6 m/s are required for wind power but are not generally found in City areas. However, as this technology develops and slower wind speeds are required, this may be a more viable option for the average consumer. Also, turbines take up far more room than a solar PV system.
Question: Is solar power expensive?
The initial outlay is significant, but following this there are many financial advantages to installing a solar PV system. The Feed In Tariff and savings made on energy bills mean that the system will pay for itself and create further income for 25 years. Also, taking into account that the systems are only expected to degrade at a rate of roughly 1% per year and the systems are guaranteed for 20 years, this provides good value. As well as a sound environmental investment, it is also a solid financial one.
Question: How do I get my system connected to the Grid?
This requires the specific permission of the Distribution Network Operator (DNO), and SolarShop or our Partners assist with this part of the process and contact the necessary people to make this a simple part of the installation. For the electricity you produce but do not use, instead of installing export meters, the trend is for the Grid to pay you a fixed amount for every Kilowatt peak installed. A lot of utility companies give you the same price for your electricity that they sell theirs for, but this varies and SolarShop and Partners will assist you on which energy supplier to choose.
Question: Which electricity supplier should I use with my solar PV installation?
This varies with individual circumstances. Our expert advisors are on hand to give their professional opinion on which provider is best to go with though.
Question: Does it take long to install a solar PV system?
It is possible that a solar PV system can be fitted in a single day, but with the erection of scaffolding and preparation of the site, it is more likely to take two or three.
Question: Can any household use solar PV?
Pretty much every home is eligible, with thatched roofs proving to be the only major difficulty.
Question: Can my business utilise solar PV?

Of course - and this is becoming more and more common. For example, you now see solar powered security lights outside, whilst indoors things such as appliances, cooling systems and lights can be PV powered.

A solar PV panel doesn't necessarily have to be an 'eyesore' on your building either. With modern technology they can be built into skylights or walls, meaning that they can actually enhance the look of your building as opposed to ruining it. Furthermore, without the mounting or support structure, the process is made cheaper.

Question: Can solar PV be used to power my home?
Absolutely. It is very easy to have a Solar PV System installed in your home, which can then power your lighting, electrical appliances etc. This is best done on a south facing roof, although every eventuality can be catered for by our expert team. As is the case with Commercial PV, panels can be installed as part of the roof's tiling or structure as opposed to being mounted on the roof.
Question: How do I know what type of panelling to use?
Our advisors will help you every step of the way to decide what type of panelling is suitable for your home and where it should be mounted.
Question: What size system will I require?
This is dependent on two factors; how much space you have for panels to be fitted, and how much energy you use.
Question: Does my house have enough sunlight for PV?
A Solar PV system needs to have unobstructed access to the Sun's light for most of, if not all of every day. Weather conditions do not significantly affect the output of the panels so long as there is light.
Question: What is the effect of shading?
The effect of shading on a Solar PV System can be massive. The panels are connected in series so the system is only as effective as the least effective panel - therefore if one panel is shaded, they all are. Steps will be taken at the design stage to ensure that shading is minimised, but if there is no way of avoiding it then please contact us as other types of cell are available.
Question: How much energy would my PV panel produce?
This varies from case to case, and depends on a) the panel, and it's capabilities, and b) to what effect they are being used; i.e. are they shaded, angled in the best possible way etc.
Question: How important is the angle of the panel and what is the best angle for a PV unit to be installed at?
Dependent on the place you live, the panel should be at anywhere between a 15° and 40° angle and facing south. When this is not possible, 90% efficiency can still be reached at 10° or 50°. but the closer to the prime, the better, as this ensures maximum use is being made of the Solar PV system.
Question: Could I install a solar PV unit myself?
It is possible to do this although there are numerous benefits from leaving the job to the professionals. You only have to pay 5% VAT when an accredited installer fits your system, as opposed to the 20% you'd have to pay on your own. The systems are very expensive and while our experts leave no margin for error, self-installation puts the system, as well as you, in danger. Also, in order to receive the Feed In Tariff, a qualified MCS installer must connect the system to the Grid.
Question: How do you get the most out of your PV cells?
This is something that will discussed with you prior to the design of your system. As long as the panels are not in a shaded area, are correctly angled and facing close to south, you should be getting the most out of your investment.
Question: How long do solar PV systems last?
We offer a twenty year guarantee on all our systems, and it is expected that they will all last at least this length of time. With the correct maintenance it is predicted that PV panels decrease in effectiveness and functionality by 1% per annum. The main reason some systems fail is poor installation, which will never be a problem with U Energy.
Question: Do the PV systems require a lot of maintenance and hard work?
Giving the panels a good clean with either a hose or soapy water now and then is likely all the maintenance the system will need. The panels operate silently and efficiently, and are practically maintenance free. A top up of the anti-freeze may be required every five years, but this isn't compulsory either.
Question: What if my solar PV panels don't produce enough power?
There is no need to worry about this happening, as you will still be wired up to the National Grid, meaning any shortfall in production can be compensated for. The only time you would be without electricity is during a power cut when neither the system or the Grid would provide electricity.
Question: Can the glazed front mean light gets reflected away from the panels?
The glass is treated with an anti-reflective coating so any loss of light due to reflection is minimised. Also, the glass has a slight granular texture, which maximises the yield by reducing the effect of glare.
Question: When will it be the case that renewable energy such as solar power fully replaces the use of fossil fuels?
At present, fossil fuels such as oil and coal provide an inexpensive way of providing power, hence their widespread use. However, the UK government has committed to having 10% of our energy being produced by renewable sources by 2012, with this going up to 20% by 2020, which will see a massive decrease in the use of finite fossil fuels. Furthermore, the fact solar, wind and other forms of renewable energy are so much cleaner than solar power is a massive influence on the increase of their usage, and with the rise of global warming, more and more pressure is being put on companies and governments as a whole to use cleaner energy.
Question: How long will it be before solar powered cars exist?
While cars fuelled freely and cleany are fantastic in theory, due to the weight and inefficiency of cars it could be a while before a car that is suitable for everyday use is seen in production. Electric cars, with batteries charged by Solar technology in the daytime could possibly be an option, but as of yet, technological developments haven't come far enough to bring this to fruition.

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