TL;DR
Get backup power and energy gear delivered free with Prime
- Fast, free delivery on millions of items
- Prime Video, Amazon Music and more included
- Member-only deals all year
A Utrecht University study modeled sharing a building’s existing grid connection among 58 apartments and found that its installed 70 kWh battery could generate a net annual benefit of €25,297, with an estimated 0.55-year payback. The result depends on a notional arrangement whose legal and contractual feasibility was not assessed; in the building’s current setup, the modeled payback is about 3.3 years.
A shared 70 kWh battery at a 58-apartment building in Utrecht could pay for itself in about 0.55 years if the apartments’ individual grid connections were consolidated into the building’s existing connection, a Utrecht University study estimates. The researchers stress that this is a modeled scenario: they did not determine whether the consolidation is legally or contractually possible.
The study examined a renovated 1970s, 10-story building owned by housing corporation Bo-Ex. It has 356.6 kWp of solar panels integrated into its roof and facade, heat pumps, and two batteries with a combined 70 kWh of storage and 60 kW of discharge power. About 175 kWp of solar capacity serves shared facilities, while 181.6 kWp sits behind individual apartment meters.
Using measured hourly data from 2022, the researchers modeled battery operation and included battery degradation costs. In the shared-connection scenario, all 58 apartments would be placed behind the facilities’ existing 110.4 kW connection. The combined solar exports would exceed that connection’s limit for 122 hours in a year, mainly around summer midday. The researchers found the installed battery could cover those modeled hours, allowing the building to avoid 58 individual connection charges.
At the study’s cited Stedin tariff of €350.45 per connection annually, dropping those 58 connections would save €20,326 a year. After capital and degradation costs, the modeled 70 kWh battery produces a net annual benefit of €25,297. The study puts the economic optimum near 280 kWh, with a net benefit of €32,829 a year and an estimated payback of 1.7 years. Those figures are model results, not observed savings from an implemented shared connection.
Connection Charges Drive the Payback
The study’s central finding is that, for this building, the largest modeled financial gain comes from avoiding individual grid-connection charges, not from fine-tuning when the battery charges and discharges. That matters to apartment owners and housing providers considering storage: the value of a battery may depend as much on how electricity connections are organized as on battery size or solar output.
The contrast with the building’s current arrangement is substantial. At present, the batteries serve shared facilities rather than all apartments. In that setup, optimized operation raises the facilities’ solar self-consumption from 37.4% to 53.4%, producing a modeled net benefit of €4,227 a year and a payback of about 3.3 years. The modeled connection-sharing case changes the economics chiefly by removing annual charges, although residents’ ability to choose suppliers and the treatment of shared energy remain unresolved issues identified in earlier project work.
The result is specific to one building, its tariff and its measured energy flows. It does not establish that other apartment buildings would see the same savings, or that residents can be moved onto a shared connection under existing rules.
Products Worth Considering
Jackery Solar Generator 1000 V2 with 100W Solar Panel, 1024Wh LiFePO4 Battery
Jackery Explorer 300 Portable Power Station with SolarSaga 100W Solar Panel
Samsung Galaxy Tab A11+ 11-Inch Tablet, 6GB RAM, 128GB Storage, Expandable, Gray
As an affiliate, we earn on qualifying purchases.
A Renovated Building Under Study
The building was renovated to an energy-positive standard in 2019 and 2020. During 2022 it consumed 200 MWh and generated 255 MWh, according to the study. Researchers compared modeled battery dispatch against measured hourly operation, and also considered the control system installed with the batteries, which was configured for solar peak shaving.
Across 7,895 hours with valid metering, the default control system produced 37.5% self-consumption at the shared facilities, compared with 37.7% in a simulation without a battery. Optimized dispatch of the same 70 kWh battery reached 52.8%. The researchers said the installed control had little opportunity to act because flows at the facilities did not approach the connection limit. They also cautioned that their optimization assumes perfect foresight, making it an upper bound rather than a guaranteed real-time result.
The study credits no revenue for exported solar electricity, a choice the researchers said reflects the expected end of Dutch net metering on January 1, 2027. It combines 2022 operating data with 2024 Stedin tariffs and an average household electricity price of €0.40/kWh for 2022. The researchers note that hourly data may make self-consumption figures slightly optimistic and that 2022 had above-average solar irradiation in the Netherlands.
“The connection-consolidation scenario is notional; the study did not assess whether it is contractually or legally possible.”
— Utrecht University researchers, as described in the study
Legal and Tariff Questions Remain
The main unanswered issue is whether the building can actually consolidate 58 apartment connections into its facilities connection under applicable contracts and rules. The study does not resolve that question. An earlier Apt-Bat project report said a June 2024 amendment to the Dutch Energy Act made energy sharing possible, but also identified residents’ right to choose their electricity supplier and unclear tax treatment as barriers for apartment buildings.
Other limits affect how broadly to apply the estimates. The analysis covers one building and one year of hourly data, while 2022 was sunnier than average. It uses 2024 grid tariffs alongside 2022 operating figures, and hourly intervals may obscure shorter-lived peaks. The study also finds no additional financial benefit from peak shaving at the site under Stedin’s capacity-bracket tariff: reducing modeled peak imports to about 56 kW does not cross a tariff threshold. Per-kilowatt capacity pricing would change that calculation, the researchers said.
Battery replacement costs also affect the modeled best size. Varying those costs by 50% in either direction moves the estimated optimum from 245 kWh to 350 kWh. The study reports that the 70 kWh system’s payback remains under one year across those replacement-cost variations in the shared-connection scenario, but that does not settle whether connection consolidation can be implemented.
The study does not announce a change to the Utrecht building’s electricity connections or a date for implementing one. The next practical step would be to establish whether residents, the building owner, suppliers and grid operator can agree on a shared arrangement that complies with rules on supplier choice, billing and tax. Until that is resolved, the 0.55-year payback should be read as a scenario result rather than a forecast of a scheduled project.
The wider market context may increase interest in the question. Dutch New Energy Research forecasts about 5 GWh of new storage across market segments by the end of 2026. The Netherlands Authority for Consumers and Markets has advised households to use more of their own solar power as feed-in charges affect returns after net metering ends. Neither development confirms that apartment connection sharing will be approved or adopted; the Utrecht study supplies an economic case for examining it, while the regulatory and contractual path remains open.
Key Questions
What did the Utrecht University study find?
It modeled a scenario in which 58 apartments share the building’s existing grid connection. In that case, the installed 70 kWh battery could help avoid individual connection charges, producing an estimated net annual benefit of €25,297 and a payback of about 0.55 years.
Is the building already using one shared connection?
The source describes connection consolidation as a notional scenario. It does not report that the building has switched to a shared connection or that the change has been approved.
How does the estimate compare with the current setup?
In the current arrangement, the batteries serve shared facilities. The study estimates a net benefit of €4,227 a year and a payback of about 3.3 years under optimized dispatch in that setup.
Why does the shared-connection model improve the economics?
The main modeled gain is avoiding 58 annual grid-connection charges, totaling €20,326 at the cited Stedin tariff. The researchers found that peak shaving added no savings at this site under the existing capacity-bracket tariff.
What remains unresolved?
The study did not assess whether consolidating the connections is legally or contractually possible. Supplier choice, tax treatment, the limits of applying a single building’s results elsewhere, and the performance of real-time controls also remain open questions.
Source: ess-news.com
