TenneT concludes ‘first of its kind’ time-limiting contract for 1.2GWh battery

Transmission system operator TenneT and Dutch green energy supplier GIGA Storage have concluded what they are calling the first-ever time-limited contract, allowing the GIGA to connect a 300MW/1,200MWh battery to the power grid.

The partners call the contract an important step forward in more efficient use of the existing electricity grid.

The new agreement gives GIGA Storage the right to take electricity from the grid or feed it back at least 85% of the time.

The new contract type developed as part of the ‘Landelijk Actieprogramma Netcongestie’ (National Grid Congestion Action Programme), allows GIGA Storage to connect its battery project, GIGA Leopard with a capacity of 300MW and storage capacity of up to 1,200MWh, in Delfzijl to the electricity grid.

According to TenneT, the contract ensures that scarce grid space is used more efficiently; a necessity as congestion on the grid now means that connections with a full and fixed transmission right are not always possible.

The grid operator also says the new contract is attractive for customers because they can get a discount of up to 65% on transmission tariffs.

TenneT CEO Manon van Beek commented in a release: “This agreement with GIGA Storage is a crucial step in improving the efficiency and reliability of our current electricity grid.

“With this time-based form of contract, we can make better use of the available capacity and connect more customers who use the grid outside peak hours.”

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According to TenneT and GIGA, the battery helps keep the power grid stable by providing extra power when needed. This can be cheaper and more efficient than switching on traditional power plants.

The battery also stores electricity when prices are low so that it can be used later when demand is higher. As a result, green power is better utilised and energy remains affordable.

Said Ruud Nijs, CEO of GIGA Storage: “With this new contract, we show that by working together, we can come up with very good solutions. By listening carefully to each other we really take the energy transition a step forward and make a significant contribution to a more sustainable and stable energy supply.”

The new agreement with TenneT will start on 1 October 2025.

To complement the current firm transmission law, the Netherlands Authority for Consumer and Markets ACM) gave the green light to time-based and time-block contracts in July 2024.

Time-based contracts enable the connection of large consumers to the electricity grid, where the connection is available for a minimum of 85% of the time.

According to TenneT, this type of contract is only for their large business customers, who pay a reduced transmission tariff and possibly make room for other parties on the waiting list.

These new contract types are particularly interesting for companies, states the operator, who do not have ‘24/7′ business processes and are offered by grid operators as an alternative to the existing fixed transmission right.

TenneT adds that, as per their position paper on BESS, to ensure a stable electricity grid in the coming years, more flexibly deployable power in the form of batteries, among other things, is needed.

The operator specifically cites the capability of battery tech to maintain stability in the grid, including for voltage management, dynamic stability, control and reserve power and redispatch.