In brief
The 100 MW / 200 MWh Antares battery storage facility in Waddinxveen has entered commercial operation. Directly connected to the Dutch high-voltage grid, the project demonstrates how large-scale batteries can support the integration of renewable electricity and provide flexibility for an increasingly electrified economy.
On 5 October 2026, Dutch energy storage developer Return announced the start of commercial operations at its Antares battery energy storage system (BESS) in Waddinxveen, South Holland.
The facility provides 100 MW of power and 200 MWh of energy storage capacity and is connected directly to TenneT’s 150 kV high-voltage network. Following construction, grid connection, commissioning and extensive testing, Antares became operational ahead of schedule.
From variable renewable electricity to flexible supply
As the Netherlands expands wind and solar generation, the electricity system increasingly requires flexibility to balance generation and consumption.
Antares can absorb electricity when supply is abundant and return it to the grid when demand or market conditions justify discharge. With 200 MWh of nominal storage capacity, the system could theoretically deliver its rated 100 MW for approximately two hours, disregarding operational limitations and conversion losses.
Unlike a power plant, the battery does not generate electricity. Its contribution lies in shifting energy over time and responding rapidly to changes in the electricity system.
Integration into the high-voltage grid
The direct connection to TenneT’s 150 kV network allows Antares to participate in electricity markets and provide large-scale flexibility.
The project was technically implemented with Alfen and SPIE Nederland. Its construction and grid integration required coordination with TenneT, followed by commissioning and operational tests.
Antares is designed to support the integration of variable renewable energy and improve the flexibility of the Dutch electricity system. Whether it reduces local congestion in practice depends on grid conditions and operating strategies.
Commercial operation and investment
The project represents an investment of approximately €85 million. Financing was arranged with participation from ING, Meewind and Nationaal Groenfonds.
Return has also concluded an agreement with Vattenfall covering 50 MW of Antares‘ power capacity, allowing the energy company to incorporate battery flexibility into its electricity portfolio.
The facility illustrates the emergence of battery storage as an operational and commercially integrated component of Europe’s energy infrastructure, rather than merely a technology demonstration.
W2E perspective
Antares is an example of the infrastructure required for Europe’s transition towards a more renewable and electrified energy system.
Large batteries can help accommodate fluctuations in wind and solar generation, reduce the need for other short-term balancing resources and improve the use of existing electricity infrastructure.
However, the environmental benefits cannot be derived from installed capacity alone. They depend on when the battery charges and discharges, the electricity generation displaced, round-trip efficiency and the operational role of the storage system.
The next indicators to watch include annual energy throughput, actual operating patterns, contributions to grid balancing and congestion management, and independently assessed greenhouse-gas impacts.
Antares demonstrates that grid-scale battery storage is becoming an established part of Europe’s electricity infrastructure.
Category: European News – Power Industry
Country: Netherlands
Location: Waddinxveen, South Holland
Developer/operator: Return
Commercial operation announced: 5 October 2026
Power rating: 100 MW
Energy storage capacity: 200 MWh
Nominal full-power duration: 2 hours
Grid connection: TenneT, 150 kV
Investment: Approximately €85 million
Technical partners: Alfen, SPIE Nederland
Commercial partner: Vattenfall (50 MW capacity agreement)
Sources
- Return – Antares is live: 100 MW / 200 MWh battery enters commercial operation, 5 October 2026.
- Return – Construction of Antares battery storage in Waddinxveen, 24 April 2025.
- Return – Vattenfall agreement and battery storage portfolio, 31 August 2026.