The operation of the Battery Energy Storage System to start during the summer

Hitachi Energy and TVO signed in the summer of 2021 a turnkey contract on a Battery Energy Storage System with an 85 MW output. The Battery Energy Storage System is designed to support, fort its part, the overall energy system in case of any production disruptions at the Olkiluoto 3 plant unit (OL3) and thus to reduce the impact of power fluctuations on the national grid.

The construction of the Battery Energy Storage System started in the summer of 2021 with earth construction works after the Municipality of Eurajoki had granted the project a building permit. TVO's BESS project comprises five equipment halls which will house the battery sets and the power electronics needed to connect the batteries to the grid. A station building with a control room and an electrical equipment room will also be erected on the site, as well as auxiliary and switching transformers and a high-power main transformer.

Battery Energy Storage System is activated in response to an operational occurrence at OL3 plant unit

In addition to the construction of the actual Battery Energy Storage System, the project entails an extension of TVO's existing 110 kV open switchyard for connection of BESS to the national grid and a new 110 kV cable connection between BESS and the 110 kV switchyard.

–The BESS project has reached the commissioning testing phase. At the same time, final installations are ongoing on the site. The extension of the 110 kV switchyard has been completed and the switchyard as well as the BESS main transformer which is supplied through it have been taken in service. The commissioning tests of BESS proceed in small packages, one block at a time. The final testing phase consists of performance and network tests that cover the entire Battery Energy Storage System, Project Manager Jarkko Latva from TVO describes the current worksite status.

The operation of the Battery Energy Storage System is to start during the summer. The EPC (Engineering, Procurement, and Construction) delivery model covers all the work phases from earth construction to the Battery Energy Storage System and the extension of the switchyard.

The BESS project currently employs on the worksite a staff of ca. 20–30 persons from Hitachi Energy and their subcontractors. TVO's own personnel is in charge of the design of connections and implementation to other necessary, existing TVO systems.

The Battery Energy Storage System will contribute, for its part, to securing an uninterrupted supply of electricity in Finland. The primary purpose of the Battery Energy Storage System is to serve as backup power capacity which is activated in case of unexpected production disruptions at the OL3 power plant unit. TVO has invested in its own battery storage and offered it to Fingrid as part of the OL3 system protection scheme.

The modern battery storage about to be taken in service in Olkiluoto is one of the largest in Europe. The batteries which are activated in response to any production disruptions at the OL3 plant unit have a capacity to supply electricity for about 45 minutes. Longer energy storage times are still a long way away.