Swedish Biomass Plant Gains Island-Mode Capability With Turbine and Battery Upgrade

A municipal heat plant in Gislaved, Sweden, has evolved from a straightforward biomass boiler into a local energy resilience hub — without constructing an entirely new power station. The 2025 expansion added a second turbine and a battery storage system, building on equipment that operator Gislaved Energi has run since 2021.

The facility has relied on heat from wood chip combustion to drive a 200 kW Organic Rankine Cycle (ORC) turbine since 2021. Last year a second ORC unit rated at 99.9 kW was commissioned alongside a 500 kW / 1,000 kWh battery. The two turbines combined are capable of generating close to 1,100 MWh of electricity per year.

The primary aim of the upgrade was island-mode operation — the ability to keep the plant running when the external grid fails. During an outage, the turbines continue generating electricity while the battery maintains stable voltage and frequency. Provided fuel reaches the boilers, the station acts as an oversized uninterruptible power supply while still delivering heat to local residents.

Under normal grid conditions the combined system creates additional revenue streams: the battery trades on price arbitrage and provides ancillary services to the grid, while the turbines reduce the facility’s own electricity costs. The Gislaved project demonstrates how integrating proven technologies can substantially strengthen the energy resilience of municipal infrastructure without building from scratch.

Source: Bioenergy International