Battery ensured 30% increased grid capacity

Eidsiva Vekst's battery service Peak Shaper has installed a 1 MW/1 MWh battery in Tensio's network in Lierne in Trøndelag. In the test, a load bank was used that can draw 1.1 MW for various tests over three days.

The testing ended with a constant load of 1 MW being connected for six hours. The operating mode that was used to achieve this is the same that Peak Shaper and Tensio have used for over 2,000 hours straight through the 2023/2024 winter season. The long-term test confirms that Peak Shaper's battery has properties that provide better utilization of the grid beyond the battery's own active effect.
In December 2022, Tensio and Peak Shaper installed a battery in a weak point in the 22 kV grid at Lierne where they have struggled with low voltage levels for periods. The point in question is near a land-based breeding facility, the industrial bakery Baxt and Li Skifer far out on a radial, 42 kilometers from the nearest transformer station.

R&D project

The battery was set up as an R&D project by Tensio, which leases the battery service from Peak Shaper. The purpose of the project was to see if batteries can help solve the voltage challenges Tensio experienced in the grid.

The battery was set up with voltage support in October 2023, and it has worked to raise the voltage continuously until today. After the battery delivered very promising results throughout the winter, it was decided to test whether the increased voltage level from the battery was enough to connect more load to the grid.

Twelve different tests

Over three days, twelve different tests were carried out, with, among other things, varying degrees of voltage support, different loads and error handling tests.

One of the main discoveries was that the Peak Shaper was able to charge the battery with an output of 600 kW while supporting the grid. During this test, 1.1 MW was consumed from the load bank without the voltage falling below the limit value for the delivery requirement.

In total, in this experiment there was an increased load from the transformer in Nordli of approx. 1.7 MW. This corresponds to a load increase of approx. 50 percent  compared to if the battery and load bank were not connected.

Not too low voltage level

The basic load on departure, without battery and load bank, was between 3 and 3.5 MW, and in heavy load up to 4.2 MW. Based on the fact that the voltage during the testing had a consistently higher voltage level than if both the load bank and the battery had been disconnected, Tensio is confident that the increased load of 1 MW does not lead to too low a voltage level, even in periods of heavy load.

Together with Tensio, Peak Shaper has gradually improved the layout of how the battery should be operated in order to support the network as best as possible. Already in September, published test results were used to improve the setup for operating the batteries through the winter.

After the testing in Lierne before Easter, Peak Shaper and Tensio are ready with a third version of the operating parameters that provide an even better voltage support and less loss than before. There is also already a plan for a fourth version, which is expected to provide further improvements.

The graph shows

As shown in the graphic figure, the battery works with the voltage support parameters used throughout the winter. The following can be read from the figure:

1. The battery works with voltage support parameters that are used throughout the winter.
2. at 09.00 The cargo vessel is started and consumes 1MW.
3. at 12.00 The battery is set to use the new and improved voltage support parameters.
4. at 12.45 Due to a human error, V2 of the parameters is reactivated.
5. at 13.30 The V3 parameters are reactivated again.
6. at 15.00 The cargo vessel is stopped after 6 hours in continuous operation.
7. at 15.05 The battery voltage support is stopped

From the graph, it can be seen that both the battery and the load vessel significantly affect the voltage in this network. One can also read that with the help of the battery's support, the voltage quality is maintained at a relatively similar voltage level compared to the reference voltage. The reference was taken at a time when both the battery and the cargo vessel were disconnected. Without the voltage support from the battery, the voltage level in the grid would be lower than the limit Tensio uses when planning new load.

Contribute with reactive effect

The main key to voltage support in weak grids is to compensate with reactive power to keep the voltage up. Since reactive power is generated in the inverter, and is not the same as active power, which is stored in the battery, it opens up the possibility of being able to charge the battery at the same time as supporting the voltage.

This means that the battery can be used for other tasks in parallel with the voltage support. The battery at Lierne offers 1 MW to the flexibility market, while also working with voltage support, which means that the rent of the battery can be reduced.

Computer simulation

Computer simulation using NETBAS has throughout the pilot project been an important tool for choosing the right parameters in the preparation of tests. It has been repeatedly shown that the computer simulations give a good indication of how the grid responds to the battery's deliveries. The use of computer simulation has also given Tensio and Peak Shaper good learning on how batteries can be dimensioned to work with voltage support. We can now say with great certainty what effect the battery can give in a network, and what size should be chosen at different locations in the network.

Complete battery service

In addition to starting work on analyzing the large amounts of data this test has provided, Peak Shaper is working on realizing more battery deliveries for completely different tasks. Experience from the various applications will enable us to offer a complete battery service that spans many different areas of use. In addition to our own projects, we also try to have a dialogue with other actors who work with batteries in the network.

Arva's "Smart Senja" project is one such player with large batteries in the network that provide voltage support. The way they use the battery to support the grid is somewhat different, but it is inspiring and instructive to see how they use the technology compared to what we do.