Q. What is the Feed-In Tariff Scheme?

A. The Feed-In Tariff Scheme (FIT) is a government backed scheme where energy suppliers have to make regular payments to householders and communities who generate their own electricity from renewable or low carbon sources such as solar electricity panels(PV). All payments are TAX FREE, Retail Price Index (RPI) linked and have a 25 year Government backed guarantee.

Q. What is the cost of a solar PV system?

A. The over generous government feed-in tariff has resulted in many shoddy installations being provided using cheap sub-standard materials and equipment by “get rich quick” individuals and companies promising inflated returns only to disappear when their systems failed to perform as stated or stopped working altogether resulting in customers losing their entire investment.

Cheap inefficient short life Panels simply clipped on roof tiles with high repair and replacement costs can be blown off in strong winds with potentially disastrous and fatal results. Cheap Inverters can lose up to over 1 kW of the solar energy generated meaning a 3kW solar system’s output is reduced to only 2kW and the resultant energy loss is equivalent to a 1kW electric heater with a serious risk of starting a serious fire resulting in burning down your property and causing deaths.

Alternatively you can choose reliable quality systems with various levels of guarantees, limitations and exclusions to reduce repair and maintenance costs but your investment is still at risk as the cost of repair or replacement can cost thousands of pounds. For example with scaffolding etc it can cost over a thousand pounds to replace a single Panel or several thousand pounds to replace the Inverter.

With Solardirect professionally designed, quality equipment, specialist installation and 25 year comprehensive guarantee on all equipment, workmanship and performance your investment is completely secure and risk free - by far the safest and best overall return on investment.

It is essential that the ‘whole life’ cost of your solar system is considered and not just the initial cost. Cheap low efficiency Equipment with short life and high repair or replacement costs quickly and greatly exceed the cost of investing in a quality system initially. Sadly Solardirect continues to receive calls to replace badly installed, faulty, dangerous, inefficient and faulty systems. Ask yourself the question: “Do I feel lucky” and risk losing my investment  or choose Solardirect’s 25 year comprehensive guarantee on all equipment, workmanship and performance where your investment is completely secure and risk free – by far the safest and best overall return on investment.

Solardirect current price list for complete standard installations;

Q. How much roof space do I need?

A. You will need at least 1.62 square metres for each panel plus a 200 mm border around the outside of each Panel Array

Q. Does my roof have to be south facing?

A. Solar panels work best on un-shaded roofs that face south and south east or south west.

Q. Will the slope of the roof affect how the solar PV panels work?

A. A 30 – 40° pitch is ideal, but most pitched roofs are suitable and A frames can be used on flat roofs.

Q. Do the solar PV panels only work on a sunny Summer’s day?

A. Solar PV panels only need light in order to produce electricity. They work best in bright sunlight but still produce electricity on a cloudy day. Solardirect systems are designed to extract maximum posible electricity under all day light conditions for the longest time each day.

 Q. Will I need planning permission?

A. Not normally, if you live in a listed building or a conservation area check with your local planning authority.

Q. How long does it take to fit the solar panels?

A. Approximately one to two days, dependent on the size of the installation.

Q. How do I know that the panels will be installed correctly?

A. We are fully qualified and experienced and give a 25  year parts and labour guarantee.

Q. Will there be much disruption?

A. There will be minimal disruption during installation.

Q. What about maintenance of the solar PV panels?

A. Solar direct provides a complete 25 year parts and labour guarantee.

Q: Monocrystalline vs Polycrystalline Photovoltaic Cells

A: The main ingredient in most photovoltaic cells is silicon – the same element that makes computer chips possible.  Silicon is the second most abundant element in the Earth’s crust, but unfortunately it is normally found in the form of silica (the chemical symbol for silica is SiO₂) – you might know it as sand. Various methods exist to extract the pure silicon, but the most common is carbothermic reduction, where the silica is heated to 1700°C in the presence of carbon.  As the silicon cools it forms crystals.

The speed at which the silicon cools is one of the critical factors that determine the crystal size: the slower the silicon cools, the larger the crystals.  With care the silicon can be extracted as one large crystal.  As you might imagine, that’s more difficult, which means it’s more expensive. The difference between monocrystalline vs polycrystalline solar cells is simply that one is produced from a single crystal of silicon and the other is produced from a piece of silicon consisting of many crystals.  So what is the impact on cell performance?

Since polycrystalline cells contain many crystals, they have a less perfect surface than monocrystalline cells.  This means that they absorb slightly less solar energy and produce slightly less electricity per square metre. On the plus side, the process of creating the silicon for a polycrystalline cell is much simpler, so these cells are generally cheaper per square metre.

On balance, the cost of monocrystalline vs polycrystalline based panels per Watt of power output works out about the same, but the polycrystalline panels will be slightly larger than equivalent monocrystalline panels.  This is generally not a problem unless you have a very limited area available for the installation, in which case you will want to maximise the power output per square metre.

Monocrystalline and polycrystalline can also look different.  Monocrystalline cells will usually have a perfectly uniform appearance, but polycrystalline cells will appear “grainy” – think of how a granite worktop looks and you’ll get the idea.  From a distance this will not be noticeable, so if they are going on your roof this is unlikely to worry you.

Q: So which Panels should I choose?

A: At the end of the day, unless you are very space constrained, your choice of panel will probably be dictated by factors other than whether they are made up of mono or polycrystalline cells. The price per Watt is an important factor, and that is largely unaffected by the choice of monocrystalline versus polycrystalline cells.  In some circumstances, the area available for the installation may be a factor that pushes you to go for monocrystalline cells. But the most important thing is to make sure that you choose a reputable installer and manufacturer.  Your panels will most likely give you many years of trouble free operation, but for your own peace of mind you will probably want to choose a manufacturer that is likely to be around for long enough to honour the terms of the guarantee – which may be up to 25 years!

Q: What are Watts?

A: To calculate the potential revenue that a PV Solar System can generate, we need to know both the value of each unit of electricity and the number of units that can be expected to be generated each year, termed “annual output” and measured in “kilowatt-hours” or “kWh”. Annual output is a function of a PV Solar System’s peak capacity (measured in “kilowatts peak” or “kWp”), the amount of solar energy reaching its panel(s) (called “insolation”), and a performance factor that allows for the alignment of the panels in relation to the sun, as well as the temperature and other factors.

A typical, well-sited high efficiency PV Solar System in the UK can produce an estimated annual output of up to 1,000 kilowatt-hours of electricity for every 1 kilowatt of peak capacity. Capacity is related to the physical size of the panels and the efficiency with which they convert solar energy into electricity. Efficiency is typically guaranteed by the panel manufacturer.

Annual output is forecast using meteorological data for average monthly sunlight levels for different geographical areas, allowing for weather and the number of daylight hours. Solardirect’s experience suggests that estimates properly based on this data are reliable.

Q: What is the difference between a kilowatt (kW) and a kilowatt hour (kWh)?

A: A kW is a thousand watts and a unit of power.  It measures the rate of energy conversion.  A kWh is the amount of work done, or energy used, when a kW of power works for one hour.

Q:  What is a kWp, and how does it relate to kW and kWh

A: A kWp is the kilowatt ‘peak’ of a system. This is a standardised test for panels across all manufacturers to ensure that the values listed are capable of comparison. The test conditions for module performance are generally rated under Standard Test Conditions (STC) : irradiance of 1,000 W/m2, a module temperature at 250C and a solar spectrum of AM 1.5. This spectrum can be found here, but is unlikely to be of any interest to anyone outside the industry. Suffice to say that it is a standardised test

Q: Do Solar Panels create energy?

A: A basic tenet of thermodynamics is that energy is never actually created only converted; solar panels convert solar energy from the sun into electricity rather than just creating it.

Q: What is photovoltaics (solar electricity), or ‘PV’?

A: What do we mean by photovoltaics? The word itself helps to explain how photovoltaic (PV) or solar electric technologies work. First used in about 1890, the word has two parts: photo, a stem derived from the Greek phos, which means light, and volt, a measurement unit named for Alessandro Volta (1745-1827), a pioneer in the study of electricity. So, photovoltaics could literally be translated as light-electricity. And that is just what photovoltaic materials and devices do; they convert light energy to electricity, as Alexandre-Edmond Becquerel and others discovered in the 19th Century.

Q: What are the components of a photovoltaic (PV) system?

A: A PV system is made up of different components. These include PV modules (groups of PV cells), which are commonly called PV panels; a charge regulator or controller for a stand-alone system; an inverter for converting alternating current (ac) rather than direct current (dc) is required; wiring; and mounting hardware or a framework.

Q: How does the system work?

A: Daylight hits the photovoltaic cells and is converted to clean electricity.  The inverter converts the electricity from direct to alternating current, for use in the home.  When the solar energy system is producing more power than is needed it is exported to the grid.  At night, power is imported from the grid in the normal way.

Q: What’s the difference between PV and other solar energy technologies?

A: There are four main types of solar energy technologies:

• Photovoltaic (PV) systems, which convert sunlight directly to electricity by means of PV cells made of semiconductor materials.
• Concentrating solar power (CSP) systems, which concentrate the sun’s energy using reflective devices such as troughs or mirror panels to produce heat that is then used to generate electricity.
• Solar water heating systems, which contain a solar collector that faces the sun and either heats water directly or heats a working fluid that, in turn, is used to heat water.
• Transpired solar collectors, or solar walls, which use solar energy to preheat ventilation air for a building.

Q: Will they work in the UK and during the winter?

A: Yes. Solar panel suppliers have enhanced the efficiency of solar power systems to the extent that it is now a very viable option even in cloudier climates.  The important thing to bear in mind is that solar power depends on intensity of light, not necessarily direct sunlight. So even when it’s overcast, your solar panels will be producing clean electricity to help power your home.

Q: What happens if there is a power cut?

A: Our photovoltaic systems for homes are entirely grid connected.  If there is a power cut your system is automatically switched off.  This is a safety measure designed to stop electricity leaking on to the national grid and to protect individuals who may be working to restore the power supply.

Q: Does the system need batteries?

A: No, the system is connected to the national grid.  In the night, when the cells are not generating energy, electricity is bought from the utility company in the normal way.  Any excess electricity generated during the day, for example when you are at work, is sold back to the utility company.

Batteries are only required if you want a truly off-grid solution and independence from any power cuts that might occur.  They are also required if you own a property which is not attached to the grid in order that power produced during the day can be stored for use in the evening. Batteries add significant costs to a solar system so are normally only offered on specific request.

Q: How much energy do I need?

A: According to the Energy Saving Trust, the average 3 bedroom house consumes 3,300 units of electricity (kWh) a year (cooking and heating using non electric supply). However, we always recommend that you look at your last few bills or call your electricity supplier to find out how many units you consume, you can then compare this to the output of the system we recommend.

Q: What if I produce more energy than I need?

A: Whenever your panels are producing more electricity than your home is using, it will flow back into the grid for other homes to use.  As long as you have an arrangement with your energy company, you’ll be paid for this power so you can be sure your energy bills will be even less and none of your clean, green electricity will be wasted.  This setup eliminates the need for batteries.  You can speak to your electricity provider for details or check at www.uswitch.com to check which energy companies offer arrangements like this. This is also something that Solardirect is willing to help with once a final system has been decided and your needs prescribed.

Q: Do you sell hot water systems as well as solar electric (PV) systems?

A: Yes, we sell both types of solar systems: Solar photovoltaic (PV) systems which generate electricity from daylight and solar thermal systems to heat water.

Q: What does energy conversion efficiency mean?

A: Energy conversion efficiency is an expression of the amount of energy produced in proportion to the amount of energy consumed, or available to a device. The sun produces a lot of energy in a wide light spectrum, but we have so far learned to capture only small portions of that spectrum and convert them to electricity using photovoltaics. So, today’s commercial PV systems are about 7% to 17% efficient, which might seem low.  And many PV systems degrade a little bit (lose efficiency) each year upon prolonged exposure to sunlight.  For comparison, a typical fossil fuel generator has an efficiency of about 28%.

Researchers are working on ways to convert more of the energy in sunlight to usable energy and increase the efficiency of PV systems, however.  Some experimental PV cells now convert nearly 40% of the energy in light to electricity.  In solar thermal systems (like solar water-heating roof panels), efficiency goes down as the solar heat is converted to a transfer medium such as water.  Also, some of the heat radiates away from the system before it can be used.

Q: How long will the panels take to pay for themselves?

A: The average UK home consumes around 3300kWh (or units) of electricity per annum. A typical PV solar panel system would be a 2kWp system which would produce approximately 1668kWh per year (based on 834kWh per 1kWp installed under UK conditions), which is approximately half of the expected yearly consumption. Payback will vary greatly depending on individual electricity consumption patterns and naturally, energy prices, which are projected to rise remorselessly. The time will obviously be even shorter if energy prices continue to increase in the future.

Q: How much energy do I need?

According to widely quoted figures, including those from the Energy Saving Trust, the average 3 bedroom house consumes around 3,300 units of electricity, or kilowatt hours (kWh) a year (assuming cooking and heating use a non-electric supply source). However, the only way to be certain is to look at your last few bills. For the most accurate figure you should call your electricity supplier to find out how many units you actually have consumed over a 12 month period. You can then compare this to the output of the system Planet Solar has recommended for you.

Q: How long does it take to install a Solar PV system?

A: The installation takes approximately three days, depending on what size system you have.

Q; Do I have to carry out any maintenance?

A; For most roof mounted domestic installations with a roof pitch of 15 degrees or greater, natural rain water is sufficient to keep the PV panels adequately clean. However, local conditions such as deposits from nearby chimneys, trees, bird lime etc may necessitate periodic cleaning of the array with water by hosing down once a year.

Q: What are the warranties on the modules and inverters?

A; Solardirect offers a minimum 25 year warranty on all equiment and installation work.

Q: What is the percentage power loss from an inverter?

A: On average most inverters are about 93% efficient. Some of the very latest high frequency inverters are usually around 97% efficient. The slight loss in performance is due to heat dissipation and transformer losses.

Q: Why Solardirect

• 25 year performance guarantee of power output included.
• 25 year guarantee on all equipment, parts and labour included.
• Maintenance twice a year for optimum performance included.
• Self cooling smart technology for maximum power included.
• Advanced 9x bypass technology included to reduce shading loss.
• Corrosion proof Panels, security bolts. heavy duty rails included.
• Hardened, low-iron, non-reflective, self-cleaning glass included
• Mains optimisation included to further reduce electricity charges
• Remote monitoring  and diagnosis included for optimum output
• Solardirect licensed Engineers are supported by the Solardirect Engineering Centre deliver clear professional advice and manage the installation of your complete solar system – saving you the hassle and delay of dealing with separate sales people, surveyors, project managers, installers etc.