IN Brief:
- KSS Verkko, ISSOY, and Synergi tested residential EV charging flexibility with 150 drivers.
- The pilots examined simultaneous starting and stopping of charging loads for distribution-network support.
- Customer motivation was driven more by local grid support than pilot compensation alone.
Synergi, KSS Verkko, and Imatran Seudun Sähkönsiirto have tested residential EV charging flexibility in Finland, using 150 drivers to examine how aggregated household charging can support distribution network operation.
The pilots tested the simultaneous starting and stopping of EV charging loads. The work assessed whether remote-controlled household flexibility could help local networks manage peak demand and reduce some reinforcement pressure as electrification increases demand on distribution assets.
KSS Verkko’s transmission capacity needs are expected to nearly double by 2033, while Imatran Seudun Sähkönsiirto faces similar long-term demand growth. The pilots were supported by the Finnish Energy Authority’s flexibility incentive for the 2024 to 2027 regulatory period, which allows distribution system operators to allocate up to 1% of grid operations revenue to market-based flexibility development.
Customer feedback showed that 37% of participants joined mainly to support the local electricity network, while 30% were motivated by energy-cost optimisation. Only 10% identified pilot compensation as the main reason for participating. That response suggests household flexibility can be built around service value and local grid contribution, rather than payment alone.
The tests moved EV charging from a passive load into a managed distribution asset. At household level, each individual vehicle provides a small amount of flexibility. Aggregated across a local network, charging behaviour can alter evening peaks, transformer loading, voltage conditions, and reinforcement requirements. Distribution operators are increasingly working with that level of controllability as EVs, heat pumps, solar PV, and household batteries appear behind the meter.
Depot and fleet charging are developing along a parallel route, though with larger loads and tighter operating windows. Fraunhofer ISE has modelled electric truck depot charging with PV, battery storage, and energy management, keeping fleet electrification within an existing 2MW grid connection. The modelling, set out in Fraunhofer models lower-cost truck charging, shows how storage and control systems can reduce cost while managing site import limits.
Residential EV flexibility operates under different constraints. Vehicles must be available when households need them, control signals must respect user preferences, and participation must remain simple enough to continue beyond a trial. Aggregation platforms therefore need to coordinate charging without creating unacceptable inconvenience, while DSOs need confidence that response will arrive at the right location, at the right time, and with sufficient reliability.
Location is central to the value of this type of flexibility. National balancing markets can aggregate response across wide areas, but distribution constraints are often tied to specific feeders, transformers, or neighbourhoods. A response that helps one part of a network may do little elsewhere. Effective local flexibility depends on network data, customer location, forecast demand, controllable load, and operating rules that allow DSOs to use flexibility without compromising security of supply.
That direction is also visible in network innovation programmes. Ofgem’s latest energy network innovation round covers enhanced system visibility, control, dynamic modelling, and high-energy demand point integration. The themes in Ofgem opens energy network innovation round show flexibility and data moving into routine network operation rather than remaining separate trial categories.
EV charging will continue to increase electricity demand, but its effect on distribution networks will depend heavily on how that demand is managed. Uncontrolled charging can create local peaks. Coordinated charging can absorb renewable output, shift demand away from constrained periods, and defer reinforcement where response is reliable enough. The Finnish pilots add another operational reference for a distribution system becoming more decentralised, more digital, and more dependent on controllable demand.
