How Much Energy Can Commercial Solar Panels Generate in the UK?

According to the solar panel experts at Mypower, “One of the biggest reasons for making the decision to install solar is for financial gain. At current installation costs, a solar PV system delivers electricity at a rate of around 4-5 pence per kWh including Operations & Maintenance costs. This compares with the current grid supplied rate of approximately 15-16p per unit.”

No matter the size of your business, these figures are certainly attractive. But when making the decision to install commercial solar panels for your business premises, one of the most obvious questions you’ll have is whether they’ll actually generate enough energy to justify the investment.

A solar PV system designer and installer will be able to calculate how much energy a solar PV system will be able to generate over a 12 month period. This is done using specialist software that utilizes historic solar irradiation data, typically take from a 10-15 year period, and applying specific parameters associated with your business and the proposed system e.g. Roof pitch and orientation, and the panels and inverters being used.

Understanding solar panel efficiency

This refers to the amount of received solar radiation that a panel is able to successfully convert into electricity. First generation panels had a rate of only 6% or so, whereas more modern versions can capture up to 22% - and this is improving constantly. One thing that people can forget is that efficiency does wane very slightly with every year of use, with a high-end panel producing around 85% of its capacity near the end of its lifespan, or around 25 years. A solar PV monitoring system is a very useful tool to check the output performance of your solar panels.

Factors that influence solar panel efficiency

As a business owner, your primary goal is likely to boost efficiency and improve your bottom line. Where solar panels are concerned, this means understanding the parameters that influence the function of your panels, so you can ensure you’re getting the most from them, day after day. Exactly how much energy can you expect from a solar PV system? That all depends on the following:

The size of the system

The bigger the system, the more energy generated. Bigger, more commercially intensive operations - like solar panels for industrial buildings - will require a larger system, but they typically have the necessary roof space to install them. For an office block, for example, a system of 100kWp size may be required, with around 300 solar panels and considerable roof surface area.

The number of panels

Speaking of the number of solar panels, this will obviously depend on the output of each panel. A system made of more efficient panels will be smaller but generate the same energy as a larger, less efficient one. Factoring in budget and overall available roof size, an installation team can help a business find the sweet spot between surface area, panel number and overall system output.

The position of the panels

Solar panels do not produce a uniform and consistent supply of energy. Instead, their efficiency is affected by their position, and how much solar radiation they are able to capture and convert. Usually, panels do best at a 35Ëš angle on a south-facing surface. This is not to say that it’s not worth installing them at another angle facing a different direction, only that the efficiency will be somewhat lower.

The number of daylight hours

Of course, a perfectly positioned and installed system can never perform well unless there’s adequate daylight to convert. One can’t control the regional weather and the amount of daylight hours, but it is possible to make sure that there are no shadows falling over the panels at certain times of day or year. Summer months will invariably yield more energy than grey winter months. But contrary to popular belief, cold weather is not a problem – solar panels work on light and not heat, and as long as there is some daylight, they can do their job. 

The rating of the panels

A solar panel’s power rating is given in watts and is determined according to its size and efficiency. The higher the rating, the more energy produced. Ratings can range from 250 to as much as 520 watts.

Panel condition

When installed correctly, solar panels will work well for years with very little maintenance – but they still do require some maintenance. Damage, dust or debris can understandably reduce their output.

Are solar panels capable of producing the energy your business needs?

If your business used 180,000kWh per year, you’d mostly likely need a 120 or 130kW system to cover a material amount of your requirements whilst still providing a very attractive commercial case. If you used 380 watt panels, this would equate to around 330 panels (divide the system size by average wattage in kW). But this estimate would change considerably depending on the factors above, and your budget.

Nevertheless, there are few businesses who don’t benefit from the reduced carbon footprint, savings, and even potential earnings of solar panels. Whether you need only a modest 50kW system or have a business running on an extra-large 500kW setup, solar panels are a workable solution. In fact, many larger businesses find they generate excess energy they can then sell back to the national grid at a profit.