Finnish EV pilot shows flexibility can ease grid strain

Distribution system operators (DSOs) in Finland have demonstrated that residential electric vehicle (EV) charging flexibility could become a viable tool for managing local grid constraints.

Their findings were taken from a pilot involving 150 EV drivers, with the test showing strong consumer participation and rapid response times.

It was conducted by KSS Verkko and Imatran Seudun Sähkönsiirto (ISSOY) in partnership with flexibility platform provider Synergi.

They tested the simultaneous starting and stopping of EV charging loads to assess whether aggregated household flexibility could help distribution networks manage peak demand and potentially avoid unnecessary grid infrastructure investments.

The trials come as Finnish DSOs face growing pressure from electrification and rising grid capacity requirements.

According to Synergi, KSS Verkko’s transmission capacity needs are expected to nearly double by 2033, while ISSOY faces similar long-term challenges.

The projects were supported by the Finnish Energy Authority’s flexibility incentive for the 2024 to 2027 regulatory period, which allows DSOs to allocate up to 1% of their grid operations revenue towards developing market-based flexibility solutions.

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One of the most notable findings was that households were motivated more by supporting their local electricity network than by financial compensation.

Post-pilot surveys found that 37% of participants cited helping the local grid as their primary reason for joining, compared with 30% who were motivated by energy cost optimisation.

Only 10% said the pilot compensation itself was their main incentive, challenging a long-held assumption that consumers would only engage in flexibility programmes if financial rewards were substantial.

For further insights on the project, we spoke to Jyri Tompuri, Development Manager at KSS Verkko, and Antti Hämmäinen, CEO and co-founder of Synergi.

Project deep dive 

What prompted the move from theory to live residential flexibility pilots when many European DSOs are still hesitating?

JT: We did not want to wait until flexibility becomes a forced solution to an urgent problem. By piloting early, we can learn in a controlled environment, understand customer behaviour, test operational models and build the capabilities needed to use flexibility as part of future grid planning. For a DSO, that practical learning is more valuable than remaining at the level of theoretical discussion.

AH: From our perspective, a few things came together. The Finnish Energy Authority's flexibility incentive allocates 1% of a DSO's grid operations revenue specifically for developing market-based flexibility solutions during the 2024-2027 regulatory period. That created a concrete budget line to approach DSOs. So, their financial risk of testing local flexibility dropped significantly.

Then, the larger motivations for DSOs were related to transmission capacity needs. KSS Verkko's transmission capacity needs are expected to nearly double by 2033. ISSOY faces the same structural pressure. When you see that trajectory and you know traditional reinforcement alone won't keep pace cost-efficiently, testing alternatives becomes rather urgent.

Lastly, Finland's mature energy market helped too. Consumers here are used to spot-price contracts and dynamic tariffs. The behavioural foundation for flexibility participation already existed. What was missing was someone to run the operational layer, from household recruitment to activation testing to reporting, so the DSOs could focus on what the results meant for their grid planning.

How significant is the Finnish Energy Authority’s 1% flexibility incentive in de-risking innovation for DSOs?

JT: The incentive is not the only driver, but it is an important enabler. It supports DSOs in developing flexibility capabilities early, before flexibility is urgently needed in day-to-day grid operations or investment planning.

Were you expecting “supporting the local grid” to rank above direct financial compensation as a motivation for households?

JT: I expected the financial incentive to be the main driver. The fact that supporting the local grid ranked so highly was a positive surprise and shows that local responsibility can be a real motivator for households.

AH: The strength of it surprised us. The flexibility industry has assumed for years that you need large financial incentives to move consumers. But it seems consumers are more aware of the challenges facing the energy system than we give them credit for, and they want to take an active role with their home energy assets in alleviating those pressures.

It also makes sense that households investing in new energy technologies like EVs and heat pumps want to test new tools and benefit from services that optimise their devices. Thirty-seven per cent of our pilot participants named supporting the local grid as their primary motivation, ahead of financial benefits from energy optimisation at 30%. Only 10% cited the pilot compensation.

What the data points to is a consumer segment that wants to be engaged and involved on a local level. For anyone designing flexibility programmes, that changes the starting assumption.

Does this challenge the assumption that consumers will only participate in flexibility markets if the financial rewards are substantial?

JT: It partly challenges the assumption. Financial incentives still matter, but if participation is effortless and charging costs can also be optimised in other ways, customers may see flexibility as a broader benefit. That is encouraging for the wider use of residential flexibility.

How quickly were the EV charging loads able to respond during the down-regulation tests, and why is that speed important for grid operations?

JT: The response was surprisingly fast, around one minute in the down-regulation tests. For a DSO, that is important because grid capacity can change quickly in operational situations. Fast EV charging flexibility could become a useful tool for managing local load when the network needs support at short notice.

What did the pilots reveal about EVs as a flexibility resource for managing local network congestion?

JT: The pilot showed that EVs can become a significant local flexibility resource as EV adoption grows. A single vehicle has limited impact, but aggregated charging loads can become meaningful for managing local peaks. For DSOs, EVs are both a new source of load and a potential flexibility resource.

What kinds of grid constraints or bottlenecks were the pilots specifically designed to address?

JT: The detailed use cases are still being defined. The primary purpose of the pilot was not to solve one specific, predefined grid bottleneck, but to understand in practice what kind of residential flexibility potential exists in our network area and how it could later be targeted to local grid needs.

From a distribution grid perspective, relevant use cases could include transformer-level capacity constraints or situations where EV charging creates local peak loads. Even a relatively small amount of controllable load can be valuable if it is in the right part of the network and can be activated at the right time.

At the same time, because of the limited scale of the pilot, the grid need and the available flexibility resource do not necessarily yet meet perfectly. That is an important learning. To use flexibility effectively, DSOs need better visibility into both the location of flexibility resources and the actual capacity and loading conditions in the network.

As EV adoption grows in specific areas, it may create new local peaks, but it also increases the available flexibility potential. That is why it is important to develop readiness now: to understand where flexibility can create the most value, how it should be activated, and how its impact can be reflected in grid planning and operations.

How scalable is this model beyond a 150-driver pilot? Could it work at city or national level?

JT: I believe the model can be highly scalable, especially because it is software-based and does not require heavy additional hardware installations. At city level, aggregated EV charging could become a meaningful local flexibility resource. At national level, the key challenge is not only the amount of flexibility, but whether it can be targeted to the right location and time from the grid’s perspective.

AH: The pilot was scoped to validate the approach, not to test scale. Scale really becomes a question of operational execution. For example, the Synergi app is already used by thousands of Finnish households spread across multiple DSO areas. A city-level deployment is identical to what we ran in Kouvola and Imatra but on a national level it would require broader coordination and collaboration between more players and expanding the operational scope of the pilots: finding EV owners in a specific grid area, recruiting them, getting them through onboarding, and keeping them engaged in the programme.

What were the biggest technical or operational challenges during the pilots?

JT: The pilot showed that the technical activation of flexibility can be relatively straightforward. The more demanding task for a DSO is turning flexibility into an operational tool: identifying the local need, forecasting it and activating the resource at the right time and place.

Did the pilots expose any regulatory gaps or barriers that still need to be addressed before flexibility can scale commercially?

JT: The pilots did not show that regulation prevents action, but wider commercial scaling requires a clearer flexibility market. DSOs need a model where flexibility can be bought and sold transparently, targeted to real local grid needs, and verified in practice. This is ongoing work and requires joint development across the sector.

Could local flexibility markets become more important than traditional grid expansion in some regions?

JT: Flexibility should not be seen as a replacement for grid investment. DSOs still need to reinforce the network to secure long-term capacity and reliability. But flexibility can provide more room to manoeuvre it can help time investments better, target reinforcements more accurately and manage individual peak-load situations more cost-effectively.

Were there concerns around customer trust, privacy, or control over household energy assets?

JT: Customer trust is key to flexibility. Although no major concerns came up during the pilot phase, cybersecurity, transparency, and the customer’s sense of control must be ensured before flexibility for households can be scaled up.

What business models could emerge for DSOs, aggregators, and consumers if flexibility becomes mainstream?

JT: It will be interesting to see how the flexibility market and business models develop. With smart decisions, I believe flexibility can become a win-win-win model: customers benefit from easy participation and optimisation, aggregators can build scalable services, and DSOs gain a new tool for managing peaks and planning investments more efficiently.