Romania’s imbalance costs are creating a new commercial incentive: suppliers need controllable flexibility to avoid imbalance costs (“penalties”) when delivery overshoots forecasts. Delta Green argues this is the country’s defining opportunity – ‘it’s not for ancillary services from very beginning but it’s for imbalance’ – and that household PV and batteries can be aggregated and dispatched as a practical response, with part of the avoided imbalance costs shared back to participating households. Once there is enough households in the block, it can be used for ancillary services.
Delta Green is a Czech based company positioning itself as a technology provider for retail suppliers, built to connect household assets and turn them into a controllable “virtual battery” that can be activated when imbalance prices spike. In a conversation with Energynomics, cofounder Jan Hicl put it this way: “50,000 different prosumers the supplier will see in his system as one unit, a virtual power plant they will operate as they like”.
Imbalance hurts everyone – and households matter
Jan framed the core operational problem in simple portfolio terms: retailers forecast delivery based mainly on weather, but reality usually overshoots. “There’s nothing they can do about it these days”, he said, adding that “everyone usually makes the very same mistake”. When that happens, “the prices of the imbalance are peaking and it really hurts everyone”.
The business logic is straightforward: when a supplier’s portfolio is long against its forecast, it can pay participating households a small fee to temporarily curtail PV export (or dispatch batteries) so the supplier moves back toward its contracted position. Because the imbalance penalty at peak moments can be very high, the supplier can afford to share only a fraction of what it would otherwise pay – so the avoided penalty can be much larger than the household payment. As Jan put it: “By lowering this, retailer can save a lot of money because the “penalty” is a lot, while payment for turning it off it’s just very little”. Thus, the incentive is a revenue-share: the prosumer is paid for flexibility (temporary curtailment or dispatch), funded from the supplier’s avoided imbalance costs.
Why Romania looks different
Jan also argued Romania is one of the few European exceptions where PV-only households can still carry meaningful market value through controlled curtailment. “In Romania it works very well with just PV panels”, he said. PV-only curtailment value could be “like 20 euros a month”, market revenues. Finally, household sharing depends on the agreement with the supplier.
For batteries, the bigger point is not only revenue but functionality. “The battery is a holy grail for the flexibility because it can deliver both directions”, he said – exporting to grid and consuming from grid.
Making use of the household assets
Delta Green’s go-to-market is retailer-led. Jan explained that they “provide a technology to a third party which is usually an energy supplier who uses the technology to control or steer the households”.
A gateway, as small as a box of chocolate, is deployed at the household. It is connected to the Wi-Fi network and that’s all.
This packaging matters because the Romanian prosumer conversation is not only about economics, but also about trust. Delta Green’s practical response is to make the value exchange visible and auditable. Jan’s point is that the customer’s payment is in a certain way “a bonus on top”. However, in real life it represents a replacement for the revenue they lose when export is curtailed – and it can be set so the customer is better off than if the PV had kept exporting.
In his simplified example, the retailer tells the prosumer: if you keep exporting normally, you would earn a certain amount from selling that energy to the grid. If we temporarily stop (or reduce) your export to help the retailer avoid a costly imbalance situation, we will pay you a higher amount than you would have earned from exporting. The curtailment payment is funded from the retailer’s avoided imbalance costs, so it can afford to share part of that saving with the household. The practical outcome is that the prosumer sees a clear trade: less export at that moment, but more money overall – which helps build trust because the value exchange is transparent.
A “virtual battery” with constraints, not chaos in the household segment
On the platform side, the concept is to abstract thousands of heterogeneous homes into one controllable asset. The end customer can set “comfort preferences”, such as how much battery capacity remains reserved for self-use versus trading. “They can set some preferences how much of the battery they want to keep for themselves [and] how much for the trading on the market”, Jan said.
These preferences are “reflected to the virtual battery”, which is then presented to the retailer in an intentionally simple operational model. The goal is that retailers “don’t need to care about what’s happening in the household. We do that for them”, Jan says.
Activation is tied to market conditions: “We monitor data and when we see that there is a big price peak in the imbalance, we can automatically activate the virtual battery”.
Thousands of households in the Czech Republic
Delta Green’s reference point for adoption is the Czech Republic, where “most of the Czech market retailers are already using our platform”, and where onboarding started with E.ON and scaled to “almost 10,000 customers”. Replication is not instant, because selling the idea to the suppliers “is not easy” and then “they have to build the marketing machine and the operations machine and sell it to the end consumers”.
This suggests that for Romania, the bottleneck might be less the technology and more the ecosystem’s ability to package a credible offer, educate customers, and execute at scale through supplier channels.
Engage value-sharing model
In our conversation, we repeatedly returned to the same strategic point: imbalance is not just a technical topic; it is becoming a social and political issue. The relationship is at times tense and bitter between parts of the prosumer community and the actors expected to manage the system day to day – DSOs and suppliers. The conversation changes when households are treated as contractual flexibility providers, not as uncontrolled injections that create risk for someone else’s balance sheet.
In Delta Green’s framing, the practical pathway is a retailer-led contract and technology stack that makes households steerable without destroying their own self-consumption logic, while sharing enough value to overcome fear and inertia. And, looking forward, the same logic can extend to EV flexibility: once bidirectional charging is available, “the EVs can be a very big asset helping to the grid”, Jan said.
