Fusebox continues to scale up grid flexibility across the Baltics. We recently prequalified an additional 2 MW of mFRR up capacity and 1 MW of mFRR down capacity in Estonia, strengthening our commercial and industrial portfolio and adding a new BESS-specific portfolio. At the same time, we successfully added another 1 MW of mFRR up capacity in Lithuania, reinforcing our presence in a high-value market where mFRR prices are approximately three times higher than in Estonia.

“Growing our portfolio is one thing. Making sure every single megawatt can deliver on command is where the real challenge and value lies,” says Donatas Braziulis, Head of Portfolio at Fusebox.

Estonia: Tested, Verified, Activated

The Estonian prequalification process was conducted by Elering, Estonia’s transmission system operator. The test simulates real market conditions. Assets must respond to a 15-minute activation signal by reaching full output in 5 minutes, remaining stable for at least 10 minutes, and returning to baseline once the signal ends.

For instance, if a portfolio starts at 0 MW and is dispatched to -3 MW (feeding power into the grid), it must return to 0 MW afterward. The test is closely monitored to ensure genuine responsiveness.

“We passed on the first attempt. That speaks to how mature our platform is. Running the test is the easy part. The challenge lies in the months of technical and regulatory preparation behind the scenes,” says Donatas.

We now operate two mFRR up portfolios in Estonia:

  • A 1 MW residential portfolio designed for private customers who trade on higher price volatility
  • A 3 MW commercial and industrial portfolio composed of batteries, generators, PV systems, and industrial loads

These portfolios can now be activated up to 20 times per day, enabling over 2.1 GWh of traded flexibility each month across Estonia and Lithuania.

Lithuania: High-Value Market, Strong Entry

Fusebox also achieved prequalification for an additional 1 MW in Lithuania, where regulatory market prices are currently about three times higher than in Estonia. This gives our team a powerful entry point into a market where flexible capacity can deliver stronger returns with each activation.

“Lithuania offers a great environment to show the real-world value of flexibility. It’s also an excellent use case for potential SaaS clients who want to see a portfolio already trading, not just theory. It’s always easier to sell results than promises,” says Donatas.

This move not only diversifies our regional presence, it also reinforces our ability to operate effectively across different regulatory and market frameworks.

What’s Next

We’re continuing to grow. Plans are already underway to further expand both our mFRR up and down portfolios in Estonia and Lithuania, with more megawatts in the pipeline and new client assets being onboarded every month. In parallel, we’re also working on launching our first aFRR portfolio, opening up a new chapter in real-time balancing services for our partners.

“We’re not just adding megawatts. We’re building responsive, revenue-generating portfolios that support the grid and prove the commercial value of flexibility,” says Donatas.

Fusebox continues to unlock real-time flexibility for TSOs and asset owners through proven technology, efficient operations, and market-ready capacity.

Want to explore how your assets can generate new value? Reach out and let’s make it happen.