IN Brief:
- Delta Capacity has reached financial close on two Finnish batteries, each rated at 125MW/300MWh.
- Société Générale provides senior financing, with Finnvera supporting one facility through a counter-guarantee.
- Sungrow is supplying storage equipment, while Centrica Energy has partial tolling agreements for both projects.
Delta Capacity has reached financial close on two Finnish battery energy storage projects with a combined capacity of 250MW/600MWh. Construction is under way at Kärppiö in Teuva and AKKU One in Lapinlahti, each rated at 125MW/300MWh. Société Générale is providing senior debt financing for both installations, which are targeting commercial operation in the fourth quarter of 2027.
The French bank is acting as sole senior lender, agent, security agent and hedge provider under the financing arrangements. Finnish export credit agency Finnvera is providing a counter-guarantee supporting one of the facilities. The total debt amount has not been disclosed, although the financing commitments establish funding arrangements for projects that have already moved into construction.
Delta Capacity is developing Kärppiö alongside Strioga Family Foundation, while AKKU One is being developed in partnership with Covenergo. The two installations have separate investment structures and delivery teams, with Delta Capacity responsible for construction management and long-term asset management across both assets.
At Kärppiö, the developer has appointed Sungrow to supply the battery storage equipment, with NEPower responsible for electrical infrastructure and substation works. Despro provides local engineering services. These responsibilities form part of the construction programme established before the latest financing milestone, with the contractors now working towards completing the installation and its grid connection.
AKKU One was acquired from Helios Nordic Energy as a project ready for construction. Its electrical and infrastructure works are assigned to NYAB, with Rejlers providing technical support during construction. Ampner is responsible for grid connection studies and compliance verification, while GreenPowerMonitor, part of DNV, is supplying energy management, monitoring and data acquisition systems.
The division of responsibilities reflects the range of equipment required to bring a large battery into service. Battery containers store electrical energy, while power conversion systems manage the flow between the direct-current equipment and the alternating-current network. Transformers provide the voltage interface, with switchgear and protection equipment isolating electrical faults and maintaining the conditions specified by the network operator.
Each project’s 125MW power rating describes its nominal maximum output, while its 300MWh capacity represents stored energy. Dividing the two figures gives a nominal discharge duration of 2.4 hours at full rated power. The actual period available for sustained export will depend on operational reserves, conversion losses and the battery management limits applied to the installed equipment.
The distinction between power and energy capacity influences both the electrical design and the services a project can supply. A battery may provide rapid changes in active power during frequency disturbances, or charge and discharge over longer periods to respond to electricity market conditions. The energy remaining in the system and the available converter capacity determine which services can be delivered at any particular time.
Centrica Energy has entered partial tolling agreements for both Finnish developments. The arrangements build on the companies’ existing relationship and provide a commercial route for the batteries to participate in electricity trading and flexibility markets. The detailed contract prices and allocation of dispatch rights have not been disclosed.
Tolling agreements can give an electricity market participant defined rights to manage the operation or commercial output of a storage installation. Depending on the contract, the asset owner may receive payments associated with availability or other agreed services, while the tolling counterparty manages part of the exposure to electricity market prices. The exact balance of responsibility depends on the individual commercial terms.
Partial tolling allows different revenue arrangements to apply to portions of a battery’s commercial capability. Those commitments must remain compatible with the physical equipment, because a single installation cannot exceed its inverter power rating or discharge more energy than is available. Controls therefore need to coordinate the dispatch instructions associated with contracted services and other market opportunities.
Finland’s electricity system includes substantial wind generation, whose output changes with weather conditions. Battery installations can respond to short-term variations in electricity supply and demand, including changes that require balancing services. Their ability to deliver those responses depends on network connection conditions, state of charge and the operating limits of the battery and its converters.
Both installations will need to complete commissioning and network compliance testing before commercial dispatch begins. Electrical verification must establish that the equipment can charge and discharge within the permitted connection limits and respond correctly to protection and control instructions. Communications between the battery management system, power conversion equipment and the wider plant controller are also required for coordinated operation.
Delta Capacity previously commissioned the 70MW/160MWh Ånge battery in Sweden, which entered commercial operation in June 2026. Centrica Energy provides optimisation services for that installation, giving the companies an established operating relationship before the Finnish projects enter service. The new developments increase the nominal power and energy capacity associated with their Nordic storage activities.
Financial close follows earlier equipment procurement and commercial agreements, allowing construction to continue under the newly established debt arrangements. The remaining programme includes delivery and installation of the storage equipment, completion of the substations and electrical connections, and testing of the integrated control systems. Both Kärppiö and AKKU One are scheduled to enter commercial operation in the final quarter of 2027, subject to completion of those works.
