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Ancillary services from Bredhälla contribute to a balanced electricity grid

January 15, 2024, 13:39
Energy storage enables the transition to renewable energy production and plays a central role in the electricity system of the future. In Uppvidinge municipality in the south of Sweden, we are developing the Bredhälla BESS (Battery Energy Storage System), our first energy storage project.

The main purpose of the project is to deliver ancillary services to Svenska Kraftnät, so that the electricity grid can remain balanced at an even frequency of 50 Hertz. By fast charging or discharging of the batteries, Bredhälla will compensate for imbalances caused by a surplus or deficit in electricity production in the system. Bredhälla can also trade electricity on the market, thereby helping to reduce extreme peaks in electricity prices in the south of Sweden.

Twenty battery containers

Bredhälla has a capacity of 43 MW, distributed among 20 battery containers, all of which are now in place. OX2's construction project manager, Federico Vignera, gives an update on the construction project, which has been divided into two distinct phases.

– Kanonaden, our civil engineering contractor, was first on site and carried out groundworks, dug cable trenches, put up fences, built roads and more. Their work was completed at the beginning of the summer. When they left the project site, Nidec arrived and the installation of the containers began, says Federico Vignera.

Testing the system

Nidec is a leading supplier of BESS solutions. During the fall, they have installed and connected all the containers. In the first week of January, the so-called "cold commissioning" began. This means that all containers are energized, and the system's functionality is tested, but without any power being passed between the system and the grid.

– In the next phase, "hot commissioning" will be carried out. That means we test the system's connection to the electricity grid. We will also carry out tests to handle the ancillary services to support the frequency containment of the Swedish national grid. These tests include FCR (Frequency Containment Reserve), FRR (Frequency Restoration Reserve) and FFR (Fast Frequency Reserve). This is done to qualify as a supplier of ancillary services to Svenska Kraftnät, says Federico Vignera.

Strict safety routines

From a work environment perspective, Bredhälla differs from, for example, the nearby wind farms Karskruv and Marhult insofar as the project is confined within a fence, there are no tall cranes necessary for the installation, and the transport of the containers is done by standard trucks. Another difference is working with electrical high voltage. Federico Vignera explains:

– The batteries are partially charged when they are delivered and installed in the racks, which means that when you plug in a battery, the voltage rises to very high levels. To mitigate the risk of electrical accidents and fire, strict safety routines have been implemented for all works at the site, with regular health and safety inspections and meetings with all the contractors.

– Furthermore, all workers must wear special personal protective equipment for this type of work and only trained personnel can perform the electrical installation. We feel secure in the skills of the workers on site and in our safety routines, concludes Federico Vignera.

Monitoring environmental aspects

As on all OX2 construction sites, environmental aspects are critical. An environmental plan was established at the beginning of the project and its outcome is monitored daily by the site managers, with support from external specialists.

The plan is for Bredhälla BESS to be completed and commissioned by the spring of 2024.

Construction Project Manager, Energy Storage
Federico Vignera