IN Brief:
- E.ON has proposed dedicated grid-supporting home batteries in local areas where substations are under pressure.
- The model prioritises batteries for distribution network needs, with wider market participation when local support is not required.
- Firm, locational flexibility could help manage reinforcement delays, transformer lead times, and low-voltage network constraints.
E.ON has proposed a firm flexibility model that would use dedicated home batteries to support constrained local electricity networks.
The approach targets neighbourhoods where local substations are under pressure from electric vehicles, heat pumps, rooftop solar, home batteries, digital loads, and community-scale generation. Instead of treating domestic batteries only as household bill-saving devices, the model would allocate them to specific parts of the distribution network where they can support local operation.
Under the proposal, batteries installed in homes within constraint zones would be prioritised for distribution network needs. They could discharge when the grid requires local support and charge when doing so helps manage network conditions. At other times, the same assets could participate in wider system balancing and market activity, with revenues used to reduce household energy costs.
The defining feature is firmness. Existing flexibility schemes can provide valuable demand response, but not every flexible asset is available in the right location, at the right moment, or with enough operational certainty to relieve a specific substation. A battery connected behind a meter in the right part of a low-voltage network can be more useful to a local constraint than a larger asset elsewhere on the system.
E.ON has set out further detail in its report on how batteries can reduce fuel poverty and limit grid costs.
The proposal reflects a distribution system that is becoming more active and less predictable. Local electricity networks were originally designed around one-way flows from higher-voltage systems to homes and businesses. As more customers add generation, storage, electric heating, and charging loads, power flows become more variable, local peaks become sharper, and voltage management becomes more complex.
Reinforcement remains essential, but the delivery chain is constrained. Transformers, cables, switchgear, roadworks, outages, civil works, and skilled installation teams all require time and coordination. Where demand growth arrives faster than reinforcement can be delivered, firm local flexibility can reduce peaks, manage voltage conditions, and support additional connections while permanent works are planned or completed.
E.ON’s own infrastructure spending shows the scale of the wider challenge. The company’s €1.4bn first-quarter investment in energy infrastructure included major spending across European networks, energy retail, and customer solutions. Capital investment is increasing, but networks also need operational tools that can respond to constraints without waiting for every physical upgrade to be completed.
That operational shift is already visible elsewhere on the UK system. The launch of MW Dispatch enables distribution-connected assets to help manage transmission constraints, drawing smaller and more distributed resources into active system operation. Firm household batteries would apply a similar principle at local network level, where constraints can be highly specific and voltage-sensitive.
Battery-supported charging provides another example. Allye Energy’s MAX300 depot charging system uses storage to increase charging output where grid capacity is limited. Across homes, depots, and grid-scale sites, batteries are increasingly being used to separate instantaneous electrical demand from available network capacity.
The technical requirements are significant. Distribution networks would need reliable dispatch arrangements, robust metering, clear baselines, cybersecurity controls, maintenance processes, customer protections, and commercial structures that reward flexibility where it reduces network cost. Battery availability during constraint periods would need to be dependable enough for network planners to include it in operational assumptions.
If those conditions are met, local batteries could become part of the distribution planning toolkit rather than a consumer technology operating in isolation. Reinforcement would still provide the durable capacity required for electrification, while firm locational flexibility would help manage the transition more precisely.
