What are the key considerations for commercial solar installations on pitched roofs

The installation of solar PV on commercial properties can bring a variety of benefits for building owners and the building’s users. Before installing solar PV panels on a commercial property, however, there's a lot to think about, with key considerations including the type of roof and its suitability, the energy requirements, safety and cost.

In this blog post, we will discuss the key considerations for solar PV on commercial properties with tiled pitched roofs.

Can commercial pitched roofs include solar panels?

Flat roofs are often seen as the standard for commercial solar installations, and there is already extensive information available on the topic. Much less tends to be said about solar for commercial pitched roofs, which are found on many commercial buildings, ranging from care homes, schools and village halls to pubs, restaurants, boutique hotels and high-street shops.

Solar panels such as the Marley SolarTile® are widely used on pitched roofs in residential properties, and the same technology can be used on pitched commercial rooftops to increase the buildings’ sustainability and reduce energy bills.

Is the roof suitable for commercial solar PV panels?

When determining whether a roof is suitable for commercial solar panels, several factors will need to be thought about, and structural stability is one of the most important considerations.

Because traditional on-roof solar panels can add significant weight to a roof, the existing structure may need to be reinforced. Roof-integrated systems such as the Marley SolarTile®, on the other hand, do not add any extra weight. In fact, since roof-integrated solar panels act as a roof covering and take the place of roof tiles on a portion of the roof, the finished roof will probably weigh less.

Other things to think about when determining a roof’s suitability for commercial solar PV panels include:

• Roof size – The size of the roof will determine how many solar panels can be installed and, therefore, how much electricity can be generated. Each tile in the latest Marley SolarTile® range measures 1,134mm by 1,722mm and can generate up to 410Wp of power. Multiple panels can be installed in an array to increase capacity with adequate roof space.
• Pitch - The best pitch or angle of roof slope for solar arrays is anywhere between 30 and 45 degrees in the northern hemisphere but it will depend on your exact latitude. Therefore, the optimum angle for PV arrays on a site in Scotland will be different from a site on the south coast of England.
• Planning permission – If the roof is part of a heritage building or located in a conservation area, it may be difficult to obtain planning permission for bolt on or on roof solar systems as these can look unsightly and out of character whereas integrated panels are more aesthetically pleasing and blend in well with the surrounding roofscapes. In some instances integrated panels have been approved in planning permission within conservation areas and have even been installed on church roofs. But this is all depending on the local authority and the building in question so make sure to check with them.

Considering the energy requirements of commercial solar panels

When planning a solar PV installation for a commercial property, it’s important to understand the energy requirements of both the building and the businesses it contains.

• Solar capacity vs business needs – Commercial buildings with low energy consumption may not require an expansive solar array, while more energy-intensive operations will benefit from a larger system. Having a continuous supply of power may also be an important consideration, such as in care homes and other healthcare settings.
• Selling energy back to the grid – even if you are not consuming all the energy you are generating throughout the day any excess can be sold back to your electricity provider reducing your overall energy bills.
• Battery storage – Including solar batteries as part of a commercial solar PV system can provide greater control over energy usage. Solar batteries store excess electricity that’s generated and save it for when it’s needed. Battery storage can also provide backup electricity during power outages.
• Electrical vehicle charging – With electric vehicles (EVs) becoming more and more common on UK roads, there’s a growing need for EV charging points. Approved Document S, Infrastructure for the charging of electric vehicles, was published in 2021 and requires new builds and buildings undergoing significant renovation in England to have EV charging points if they have associated parking spaces. Opting to power the EV charging points with solar panels will help to keep costs down and allow employees or vehicle fleets to be recharged with free electricity.

Safety considerations of solar panels on commercial buildings

On any building project, fire safety is a major consideration. Solar panels are generally safe when installed correctly, but it’s also important to mitigate any potential risks to protect the building and its occupants.

Solar panels pose minimal fire risk. Research indicates that they are less of a fire risk than common household appliances like toasters or dryers. According to SolarBlogger, in the UK, there are only 15 fires per million solar installations each year. Most of these fires are the result of poor-quality electrical work.

One of the most common mistakes in solar panel installation is incompatible DC connectors being combined. Safety regulations prohibit the mixing of DC connectors from different manufacturers, but they often look similar and mismatched connectors can lead to electrical faults, increased fire risks or system failures. This is why it’s important for solar panels and associated electrical connections to be installed by qualified professionals.

Other fire protection methods should also be considered and implemented as appropriate. These include fire-separating walls, roof cavity fire barriers such as Marley Roof Defence, and Marley ArcBox, which is fitted around DC connectors to contain any electrical arcs that might occur.

Cost considerations for solar PV on commercial roofs

The cost of installing solar panels on commercial pitched roofs is another consideration for building owners to consider, and it’s important to think about both the initial investment and the long-term savings.

In terms of initial investment, there is a noticeable difference in costs when comparing new builds to retrofits. For new builds, the installation costs of solar panels can be incorporated into the roof specification, minimising additional expenses. In fact, roof-integrated solar systems, such as Marley SolarTile® can help to reduce costs, as they act as a roof covering, reducing the number of roof tiles needing to be installed. For existing buildings, it may be more economical to wait until the roof needs replacement.

As for long-term savings and return on investment, since solar panels produce free electricity, they can significantly lower a business’s operating costs. While this may not be of particular importance to building owners, the cost efficiency and sustainability can make a property more appealing to tenants, thereby helping you to retain existing tenants, attract new tenants and avoid commercial spaces sitting empty without any income. The cost of a solar array can often be appreciated within the value of the property once you come to sell therefore can be seen as cost neutral.

The Marley renewable system for commercial solar installations

From reducing energy bills and enhancing a property's appeal to improving sustainability, the installation of solar panels brings a number of benefits to a commercial property. And with careful planning, property owners can be sure to get the most out of the system.

Marley's Roof System makes it easy to specify every element of a roof, from the battens up, including Marley SolarTile®, solar batteries, fire safety products and EV chargers. All components are fully compatible, and the roof systems are provided with an industry-leading 25-year warranty.

To find out more about the Marley Roof System, and how we can support your next commercial solar project, contact the Marley team.