Solar Overshadowing: An Emerging Risk for UK Developers

With solar panels now a common feature of both residential and commercial developments across the UK, developers are navigating a growing planning challenge: the risk of overshadowing neighbouring photovoltaic (PV) systems.​

By the end of 2024, more than 40% of new-build homes were constructed with integrated solar panels. As cities become denser and environmental regulations tighten, developers are facing increased scrutiny not just from planners, but also from neighbours regarding how new buildings may affect the performance of nearby solar installations.​

In London, this issue is becoming even more relevant. The Mayor’s latest solar initiative part of a broader push to accelerate the capital’s path to net zero aims to significantly increase the number of solar installations on both public and private buildings. This policy direction is likely to increase the number of potential conflict points for developers when it comes to daylight access and overshadowing. ​

Planning Implications Are Growing

Overshadowing isn’t just a technical issue—it can have serious financial and legal implications. Even a partial reduction in solar access can diminish energy output, prompting objections from homeowners or commercial neighbours. This has real potential to delay or even derail planning approvals.​

In the case of McLennan v Medway Council (2019), planning consent was overturned because the local authority failed to assess the overshadowing effect on an existing PV system. The resulting delays, redesigns, and legal costs highlighted just how crucial solar impact assessments have become to the viability of development schemes.​

Understanding PV Overshadowing Assessments

A PV overshadowing assessment is typically carried out alongside daylight and sunlight studies at the pre-application stage. It uses advanced 3D modelling to simulate the development’s impact on sunlight reaching neighbouring solar panels throughout the year. This allows teams to measure potential energy losses and consider mitigation options before designs are finalised.​

These assessments are increasingly expected by planning officers—especially in areas like London where solar adoption is being actively promoted. They also support compliance with environmental standards such as BREEAM, LEED, and the UK Net Zero Carbon Building Standard.​

The Benefits of Early Assessment

1. Avoid Costly Delays
   An early PV assessment can help identify risks before they escalate. It allows developers to respond to neighbour concerns, satisfy planning officers, or mitigate potential impacts during the design phase—reducing the likelihood of objections later.​
2. Meet Planning and Sustainability Requirements
   Guidance from the BRE (Building Research Establishment) now includes specific considerations for PV systems. Demonstrating compliance through assessments can also support sustainability certifications such as BREEAM, LEED, and the UK Net Zero Carbon Building Standard.​
3. Enhance Your Own Solar Strategy
   Beyond risk mitigation, these assessments can inform the optimal placement of your own solar arrays—maximising efficiency and futureproofing your developments as net zero requirements tighten.​

Proactive Design Leads to Smarter Development

Carrying out a PV assessment early in the design process doesn’t just prevent planning issues it can also enhance the sustainability credentials of your own development. By optimising the orientation and placement of solar panels, developers can boost long-term energy performance, reduce operational carbon, and appeal to eco-conscious buyers and tenants.​

Incorporating these considerations at an early stage also demonstrates a responsible, forward-thinking approach to development. As planning policy evolves in line with national net-zero targets and as urban areas like London introduce more aggressive solar adoption policies this kind of foresight will increasingly be viewed as essential rather than optional.​

Growing Trend, Growing Risk

With objections related to solar panel overshadowing on the rise, this issue is no longer niche. As more homeowners and businesses invest in PV systems and as local and regional governments actively push for greater solar coverage, as seen with the London Mayor’s strategy the risk to developers is clear: ignoring this factor can cause significant delays, redesign costs, and reputational damage.​

By considering solar overshadowing early in the process, developers not only reduce risk—they demonstrate leadership in a low-carbon future.​

Technical Insight at the Right Stage

At DPR, we support developers by integrating solar overshadowing assessments into the early stages of the design and planning process. To forms part of the scope of the Daylight, Sunlight an Overshadowing review required as part of the planning application process. Using detailed 3D modelling and sunlight analysis, we help identify potential conflicts with neighbouring solar installations before they become planning obstacles.​

Our role is to provide clear, practical data that informs design decisions whether that means adjusting massing, repositioning key elements, or documenting the limited impact of a proposed scheme. This technical insight can help reduce the risk of planning delays and supports the preparation of more robust applications, particularly in areas with growing environmental sensitivity.​

As solar adoption continues to rise and climate-related considerations become more central to planning policy, early-stage analysis is becoming not just good practice, but a necessary part of development strategy.

Please contact our Partner Chris Harris for further advice.