Extreme summer weather has once again put the UK’s electricity grid in the headlines. In particular, questions have been raised about the increased penetration of solar and the potential instability that it is introducing, especially with the legalisation of balcony systems. But underlying these recent worries is a fundamental challenge: can grids built for centralised generation accommodate a surge of decentralised, variable power?

In a country like ours, with highly variable weather, accurate forecasting is a challenge compounded by the fact that a significant share of smaller-scale solar photovoltaics (PV) is not obliged to report to Great Britain’s National Energy System Operator (NESO) or register with the balancing mechanism. Much domestic or rooftop solar also lacks the telemetry to provide real-time data. This creates a blind spot in the national picture: when the sun is shining, system operators cannot be sure how much localised generation is online; and when it is not, they can’t be sure how much extra demand will appear.

National issues like generation forecasting aside, difficulties also show up on a local level as a voltage management challenge. Under normal operation, the voltage on feeders drops as cabling progresses from substations on towards the end user. However, when local demand is low and PV generation is high, it can increase the voltage in the network. As a result, the voltage may exceed safe working limits. As almost all UK solar is connected to the distribution network, this is a significant issue for distribution network operators (DNOs).

These are legitimate concerns for network operators needing to accommodate the peaky output from a significant solar facility, but they are far less important for the recently legalised balcony solar installations. For plug-in panels to become a real issue, their uptake would need to be significant – and local demand very low. Given their price point and payback period, I predict uptake will not reach that threshold. There are also alternatives that many consumers will find more attractive, such as the solar-and-battery packages that behave far more predictably on the network and which can be automated – or their owners incentivised – to charge and discharge at times that actively support network stability.

Visibility and local demand
Voltage issues and forecasting difficulties do not mean solar is incompatible with the grid. They mean the tools and technologies we already have must be deployed faster and more strategically.

Better visibility is the first step. Much of the uncertainty can be addressed by high-resolution cloud cover and solar irradiation data, for example, combined with updated grid codes to require more granular reporting for smaller distributed generation sites. Where direct measurement is not available, indirect measurement/forecasting techniques can help to make clear any of our blind spots.

On the network itself, engineering solutions such as wider transformer tap ranges that allow the fine-tuning of output voltage and larger low-voltage and medium-voltage cables will help to mitigate voltage issues directly. What’s more, using larger cables will help to future-proof the network for the electric vehicle (EV) and heat-pump demand growth already heading our way – solving two problems at once.

However, the single biggest lever to combat the instability produced by locally generated solar is local demand. If we can connect demand quickly enough that it absorbs generation close to where it is produced, then we avoid pushing energy into a network that is struggling to accommodate it. For solar farms, battery energy storage systems (BESS) are the ideal choice. But the same principle applies at neighbourhood level: EVs, heat pumps and other flexible demand sources can soak up the generation and therefore mitigate more instability at source.

This is where private network operators can help. Rather than treating generation, demand and network infrastructure separately, they can take a more flexible and deliberate approach to how they are connected. Private networks and microgrids can be designed around the strategic placement of supply and demand, keeping generation and consumption localised, and thereby reducing instability within the wider network.

BESS and the bigger picture
BESS will inevitably be part of the picture – it is hard to imagine a well-designed microgrid without some storage – but it remains one tool among several. What matters is the underlying principle of co-locating generation and demand to help mitigate instability. That is not a new idea. And crucially, having demand and generation distributed in this manner will be part of the solution to instability within countries with grids that are less developed than the UK’s.

However, the primary issues for developing nations are more often ensuring that energy demand is electrified and that people have access to stable and affordable power. Here, cheap mass-market solar can be transformative; it can be matched with equally affordable mass-market batteries.

Ultimately, the grids that adapt best to solar will not be the ones fighting its variability; they will be the ones designed to live alongside it. In both the UK and developing markets, there is the opportunity to design our grids in this way.

The views and opinions expressed in this article are those of the author and do not necessarily reflect those of the Energy Institute.

• Further reading: ‘UK regional solar installations hit record highs as government approves plug-in devices’. Official figures from the Department for Energy Security and Net Zero published on 27 August 2026 show UK solar installations reached record levels this year. Since the start of 2026, households and businesses have installed nearly 172,000 solar photovoltaic arrays nationwide.
• ‘Plugged in balconies: how micro-PV devices bring green power into European flats’. With the commercialisation of plug-in solar technology, green power generation is becoming increasingly accessible to energy consumers living in apartments and other rental properties. Across Europe, the trend is becoming visible in countries where regulation of this nascent market segment is leading the way.