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In this blog, Andy Morgan, LASER's Assistant Director Carbon & Energy Management - discusses six major pitfalls that public sector rooftop solar projects often face and provides advice on how to avoid them. These are real-life issues that our expert team has encountered and successfully resolved in public sector solar installations.

Rooftop solar, avoiding the pitfalls

Rooftop solar has matured into a reliable and proven technology, playing a pivotal role in the shift towards a low-carbon energy future. Although the technology was first discovered in 1839, it is the past decade that has witnessed significant improvements in performance and a dramatic reduction in costs. 

At today’s prices, rooftop solar makes an excellent financial payback so an economic as well as environmental case can be made. It’s also very reliable, delivers savings for 25 years or more and the annual output is very predictable.  

However, it does involve a whole host of skills to turn the desire into a reality including roofing, electrics and plenty of logistical and health and safety challenges. To install the modules onto the roofs carries inherent risks, both during installation and ongoing operations. It can raise issues about structural integrity and fire risk and remember those modules will be sitting on your roofs for decades so good design is crucial. Coupled to this, regulatory and other technical requirements continually change, so to make projects effective needs significant expertise.  

1. DNO connection

All solar installs require permission to connect from the local Distribution Network Operator (DNO). The DNO will consider the building’s existing connection to the local electricity network as well as other local impacts on the network. Some sites will be fine for a large installation, others will be limited to ensure they never export.  

There is a formal application process which can only be started once you know exactly what panels and inverters will be used i.e. the project has been fully designed. Unfortunately, this sometimes means the DNO tells you the desired solar array can’t be installed.  If this happens after you’ve employed a contractor to fully design the system then this could cost money, waste time and can occasionally mean the end of a project. 

The best way to avoid this pitfall is to develop a relationship with the DNO so that you can have early conversations and get a good steer of what will and won’t be allowable. Ensure your initial designs are developed to a point where you can take them informally to the DNO before you’ve engaged a contractor to finalise design and install. 

Rooftop solar, planning permission paperwork

2. Planning permission

Many people make the automatic assumption that all solar panel installations are allowed under ‘Permitted Development’ meaning that planning permission isn’t required and you don’t need to make an application for planning permission. 

Unfortunately, it isn’t that straightforward, a full planning application must be made in Conservation Areas, installing on a listed building or when the system is above a certain size. In addition – there are some grey areas where local planners will take different approaches in different planning authorities. For example, in some cases, if a listed building exists on a large school campus site, if you wish to install solar panels on another building (that isn’t listed) the planners may still require you to make a full application and wait for permission to be granted (or denied). 

Again, planning risks can be managed but getting it wrong can lead to significant delays, extra costs and potentially ended projects, or in the worst case having to completely remove an installed system! So, it pays to engage with planners early in your project before you’ve commissioned contractors. Know what the risks are and what the planners will need to know when you seek pre-planning advice. If you need to apply for Planning Permission leave enough time and allow for the production of drawings and design information that the planning application will require. 

3. Technical regulations

Regulations concerning the technical aspects of rooftop solar are constantly evolving. For instance, recent changes have been made to the rules regarding the placement of inverters. Additionally, incorporating batteries into the system adds another layer of complexity. It is crucial not to assume that all installers are up-to-date with these regulatory changes. 

When procuring installers, make sure to include all technical design requirements and reference all British Standards, legal requirements and guidance documents in your procurement documents. 

4. Insurers requirements

The insurance industry, after being hit across the globe with payouts due to fires from incorrectly designed or installed solar systems, have recently taken great interest in solar design specifications. Insurers will generally have a set of technical requirements which your installation must comply with otherwise the installation could invalidate your property insurance. 

We are finding that different insurers are setting different requirements, for example some are adopting technical specifications more typical in other countries and are over and above regulatory requirements in the UK. One insurer our team recently dealt with is ‘strongly advising’ the installation of external fire detection equipment as part of the install, this is technology with a very new and limited supply chain in the UK. 

Some insurers are requiring that the structural surveys consider more detailed loading calculations than standard and even requiring you to submit your planned install to them to approve before you can install. 

It’s vital to engage early with your insurers, understand their requirements, be able to converse with them and ensure that you’ve included insurers requirements within your specifications when you procure installers. 

A white male workman wearing a white helmet, on top of roof top solar panels.

5. Installer capacity and capability

The solar marketplace has experienced massive growth in recent years. While it’s great to see installation rates skyrocketing, there are some knock-on effects to be aware of if not managed properly. 

Firstly, the industry has attracted many newcomers, both new businesses and individuals who have joined the industry. Its positive that the supply chain is growing to follow demand but that does mean that some installers lack the track record and experience to be able to fully manage all risks and deliver quality installs which will last the test of time (decades!). 

The second issue is that some installers are incredibly busy and either won’t respond to tenders or will have long lead times. 

To overcome these risks, you need to plan ahead, engage early with the marketplace, ensure you have a procurement route that will attract enough attention from the market and will ensure bidders of sufficient capability. Plus, it’s important to make your project attractive, sorting out things like a good design, planning permission and DNO permission early means the contractor can have confidence that the project will go ahead, you’ll get more attention and a better price. 

6. Roof condition

The biggest delaying factor in solar projects can often be the existing roof condition. When surveying roofs for potential solar installs its vital to look at the condition of the roof covering especially with flat roofs where the roof covering may be in need of repair or replacement in the next few years. Discovering late in a solar project that the roof covering needs replacing will either end the project or introduce significant extra costs and timescales. 

In addition to the roof surface every install should have a proper structural engineer’s survey and report. This will consider whether the roof structure is capable of physically supporting the additional weight of the solar project and that the fixings are adequate to take the wind loading and uplift forces. Sometimes it’s necessary to add additional support to the roof structure or amend the design to ensure that the system stays within weight constraints defined by the structural surveyors. 

We advise completing the roof condition survey as well as the structural engineers report before engaging an installer, otherwise you risk changes to a project post procurement which will significantly affect costs, timescales and value for money. 

Take the next step with LASER as your trusted partner

While the points outlined above might seem daunting, there’s no need to navigate them alone. By partnering with the experts at LASER, you can rest assured that the risks are being managed to ensure your projects are planned and delivered on time and within budget. 

LASER has extensive expertise in supporting Public Sector organisations to take the concept and make it a reality.  We offer a free desktop solar feasibility assessment of your site to demonstrate to you and your team what’s theoretically possible. We’ll assess the suitability of solar panels across your building or even your entire building portfolio. This will detail potential panel placements and provide indicative costs and savings. 

If the figures stack up and you like the idea in principle then this is followed up by a detailed design phase. Our assessors will conduct a thorough property survey, providing you with a detailed design and structural survey. The team will manage structural engineering calculations, advise on District Network Operator (DNO) applications, and Local Planning and provide a feasibility report. 

Next step is procurement, we’ll help establish your requirements, produce technical specifications, advertise your project on our net zero framework and evaluate responses to ensure you get the best value.  

Once an installer in chosen, we’ll project manage your solar installation from start to finish. As your single point of contact, we work with your chosen supplier to ensure your project stays on track and meets the agreed timelines. 

Want to get in touch?

To find out how we can help your rooftop solar project run smoothly, email solarpv@laserenergy.org.uk or visit our solar page.

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