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Are you currently weighting the possibilities of adding a solar system to your commercial building? With lots of commercial property owners in the UK using solar now, many more are gradually coming to terms with the numerous benefits they stand to derive by getting one. Therefore, if you’re thinking about adding the system to your commercial building but do not know where to start, you’ve come to the right place.

In this post, our aim is to help you calculate the number of solar panels you’ll need to power your entire commercial building. Starting from the panels, you can begin by taking into account everything that makes use of power in your commercial building to get a good idea of how many you’ll need.

• To get started, you’ll have to determine the number of watts used by your commercial building. To get this, you simply have to go through your utility bill for kilowatt-hours (kWh). This varies amongst buildings and being able to identify your daily average energy usage will assist you in getting your solar panel needs.
• Once done, you’ll also have to determine the peak sunlight hours - having in mind that the solar panels only work when under direct sunlight. Once determined, you can then multiply the figure in hours by your home’s hourly energy usage and divide by your selected solar panel’s wattage.

In general, a medium-sized commercial building making use of an average amount of electricity will require about 70 average quality solar panels so as to cover its entire electricity needs. These are, however, just averages, so yours could be more or less so getting the idea is vital here.

Solar cells , also referred to as photovoltaic cells (PV), absorbs energy from the sun and converts it to generate electricity. This, however, should not be confused with photovoltaic thermal cells or PVT which operates to generate heat for water in homes. Solar cells are linked electrically and also carefully organized into a large frame which is popularly called solar panels. Generally, solar cells are produced or made of silicon semi conductors which works to absorb sunlight and then turn it into electricity for use at a home. A solar panel comprises of either 60 or 72 solar cells which are electrically interconnected in series and parallel and also positioned in between glass and plastic which is then framed.

At present, solar panels incorporated for residential or domestic purposes only possesses the capacity to make use of only about 20 percent of the sunlight they’re able to absorb and convert it to electricity - also called solar efficiency. Available in the market are also a wide range of solar cell available for both industrial and commercial purposes. This type of solar panels have an efficiency rating of about 40 percent which will also automatically make them more costly than the domestic types.

One great thing about the solar industry is the fact that it keeps improving in such a way that raises both its efficiency as well as overall quality. And with further research and development, this is expected to even increase as the years go by. What’s more? As these aspects keep rising, it’s also expected that the solar panels price should be on a decrease. That way, they’ll become available to a wider range of individuals who’ll also like to save money on electricity bills and go greener.

Solar panels provide an alternative to paying expensive National Grid energy rates, so primarily their first major benefit is helping to reduce bills. Solar PV panels will produce free electricity, whilst solar thermal panels generate heat for hot water and space heating. There are also payment incentives known as the Feed-in Tariff scheme (FITs) (for solar PV) and the Renewable Heat Incentive (for solar thermal) which guarantee a tax-free income for 20 years.

It’s vital to purchase a solar panel system that suits your property. If you’re investing in a solar panel system, it makes the most financial sense to get the biggest one possible. However, whether you can do this or not depends on budget and space.

Here’s an idea of how much roof or ground space you’ll need to install a few different sizes of commercial solar panel system.

Solar panel system size, No. of solar panels, Approximate area required

11kW, 44, 64m²

20kW, 80, 116m²

30kW, 120, 173m²

40kW, 160, 231m²

50kW, 200, 288m²

How much energy a solar panel produces depends on its manufacturer and exposure to the sun. A good-quality solar panel typically has a power output of about 300 watts per hour, but this can vary from about 240 to 360 watts. How much energy your solar panel will produce per day depends on how many hours of unshaded daylight it’s exposed to.

Here’s an idea of how much energy you could expect a large commercial solar panel installation to produce in a year.

Solar panel system size, No. of solar panels, Annual electricity output

11kW, 44, 9,350kW

20kW, 80, 17,000kW

30kW, 120, 25,500kW

40kW, 160, 34,000kW

50kW, 200, 42,500kW

One of the things that has been on the UK government’s agenda for some time now is to promote the use of renewable energy sources. In fact, the Renewable Energy Directive put out by the EU instructs all member countries to achieve a 20 percent renewable target before the year 2020. The UK’s commitment to this objective has been made quite glaring with a number of funding options that has been put in place to help business owners looking to solar panels on their properties. This commitment was also showcased by a reduction in the cost of solar panels, so new investors have little to worry about. Although there aren’t any grants in the conventional sense, but there are opportunities for solar panel funding in the UK. At present, the only scheme open to new applications is the SEG - Smart Export Guarantee which came into effect on 1st January, 2020.

In general, there are four notable incentives in the UK for solar panels which includes the aforementioned Smart Export Guarantee, Reduced VAT on Energy Saving Products, Feed-in Tariff ( no longer open to new applications ), as well as the Renewable Heat Incentive ( RHI - applies only to solar water heating ).

Being the only one still open to new applications, we’ll provide you with some insights on SEG. The Smart Export Guarantee allows small scale low-carbon electricity generators to receive payments for surplus energy they’re able to export back to the grid. Although, this is not a direct government scheme, all licensed suppliers are necessitated to offer an export tariff to their customers. Those suppliers with more than 150,000 customers are obligated to offer a tariff, while the suppliers with fewer customers can partake on a voluntary basis.

It’s important to get the right size solar panel system for your commercial property. Solar panels are usually installed on pitched roofs, although they can be fitted on stands on the ground if you have some unused outdoor space. The more panels you install, the more power you’ll generate, but there’s no point buying more panels than you have space for.

Solar panel system sizes are measured in kW. 4-10kW solar panel systems are usually too big for domestic properties but are ideal for smaller commercial properties. Here’s an idea of how many panels and space you’ll need for a few different system sizes:

System size, Number of panels, Area required (approximate)

4kW, 16, 23m²

6kW, 24, 35m²

8kW, 32, 46m²

10kw, 40, 58m²

Bear in mind that solar panels can’t be less than 30cm away from a roof edge, so you’ll need more space than the area that the panels take up.