Talum 1, Slovenia

Talum 1 was built in 2020 on the site of aluminium producer Talum in Kidričevo. Twelve Tesla Megapack units provide 15 MW of connected power and 30 MWh of storage capacity. The battery was formally opened on 8 October 2020. At the time it was the largest battery in Slovenia and the wider region, and the first Megapack system in that part of Europe.

NGEN chose the site because Talum already had the infrastructure and transmission connections that a system of this size needs. For decades the smelter had been Slovenia's largest single electricity consumer, taking roughly a tenth of national demand.

Talum 1 joined the same portfolio as Jesenice from its first day of operation. NGEN's software dispatched both batteries as a single resource, giving around 30 MW of capacity for secondary frequency control.

Few substations hold enough spare capacity to connect a system of this size, and the reinforcement needed to create it is a heavy cost for a network operator to carry alone. Finding a connection point is usually the hardest part of siting large storage.

Talum was an exception. Aluminium electrolysis draws a large, steady load, and the site's grid connection was sized for it. Talum also operates a closed distribution system, so it runs connection procedures within its own network and decides on available capacity and suitable connection points itself.

What the power system needed was changing as well. As wind and solar take a larger share of generation, the constraint moves from how much electricity can be produced to how quickly supply and demand can be brought back into balance. In 2020 that balancing still came almost entirely from conventional power plants.

Talum 1 sits inside Talum's closed distribution system and connects at medium voltage. The twelve Megapack units set the physical limits: 15 MW for two hours. How that capacity is used is decided by NGEN's platform.

The platform monitors grid and market conditions and adjusts charging and discharging accordingly. It dispatches Talum 1 with Jesenice and NGEN's other assets as one portfolio, which provides secondary frequency control to ELES and trades on the electricity market. The battery is monitored around the clock from NGEN's control centre in Žirovnica.

First Megapack system in the wider region

Talum 1 was the first Tesla Megapack installation in this part of Europe and the largest battery in Slovenia when it opened.

Two sites, one resource

Talum 1 and Jesenice operated as one resource with around 30 MW of capacity. At the opening, NGEN said this covered about half of Slovenia's secondary control requirement.

Existing infrastructure put to work

The battery uses connection capacity and infrastructure that were already in place at an industrial site.

The start of a storage hub

Talum 1 was the first battery at Kidričevo. Talum 2 followed in 2022, and Talum 3 is due for commissioning in 2026, which will bring the site to 105 MW / 210 MWh.