Grid Connection for BESS: What UK Businesses Need to Know Before They Start
For many businesses exploring Battery Energy Storage Systems for the first time, the technical and regulatory steps involved in connecting to the grid are an area of uncertainty. Understanding what the grid connection process involves, and how to navigate it efficiently can make the difference between a smooth deployment and a project delayed by months.
This guide sets out the key considerations for UK businesses planning a grid-connected BESS installation.
The Role of the Distribution Network Operator
In the UK, electricity distribution networks are managed by regional Distribution Network Operators (DNOs). Any significant electrical installation that connects to the distribution network, including a BESS above a certain size threshold, requires an application and approval from the relevant DNO before work can proceed.
The DNO will assess the impact of the proposed installation on the local network. This includes evaluating whether the existing network infrastructure can accommodate the additional generation or load, and whether any reinforcement works are required. For large-scale systems, this process can take several months, which is why early engagement with the DNO is one of the most important steps in any BESS project.
G98 vs G99: Understanding the Connection Standards
The connection standard applicable to your installation depends on the size and type of the system. G98 applies to smaller installations, typically below 16A per phase, and involves a simpler notification process. G99 applies to larger systems and requires a formal application to the DNO, with a more detailed technical assessment.
Most commercial and industrial BESS installations will fall under G99, which means the DNO application process needs to be factored into the project programme from the outset.
Planning Permission Considerations
Whether a BESS installation requires planning permission depends on its size, location, and whether it is being installed within the curtilage of an existing building. Many smaller commercial installations benefit from permitted development rights, meaning no formal planning application is needed. Larger systems, particularly standalone ground-mounted installations, may require full planning consent, including considerations around visual impact, noise from thermal management systems, and proximity to residential areas.
Permitted development rules for battery storage have been evolving, and it is worth verifying the current position for your specific site and system size before assuming consent is not required.
Grid Services and Revenue Stacking
Once connected, grid-connected BESS systems may be eligible to participate in grid balancing services offered by National Grid ESO, such as the Balancing Mechanism or Frequency Response services. These can generate additional revenue by providing services to the grid operator, effectively monetising the battery's ability to respond quickly to grid signals.
Eligibility for grid services depends on the system's size, technical specifications, and metering arrangements. Not all commercial BESS installations will qualify, but for those that do, grid services revenue can significantly improve the financial case for the investment.
Working with a Specialist Provider
Navigating the grid connection process, planning requirements, and grid services landscape is complex. Working with a specialist BESS provider that has experience of taking projects through these processes, including managing DNO applications, coordinating with planning authorities, and setting up grid services agreements, removes this complexity from the client and ensures the project moves forward without avoidable delays.
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-> Read: Battery Energy Storage Systems: The Complete UK Business Guide for 2026