The 20 MW district heating biomass boiler house in Šiauliai is a fully integrated, turn-key renewable heating solution designed to achieve high seasonal efficiency and ultra-low emissions. Commissioned in 2025, the plant combines robust biomass combustion technology with advanced flue gas heat recovery and emission reduction systems, enabling efficient and flexible heat production for the district heating network.

The total installed thermal capacity reaches 20 MW, with 15 MW provided by the biomass boiler and the remaining output recovered through a two-stage flue gas condensation system and absorption heat pump (AHP).

Main scope of supply and key systems

Moving Floor Fuel Storage and Fuel Handling System
The boiler house is equipped with a moving floor biomass warehouse, ensuring reliable fuel unloading, storage, and continuous feeding. The integrated fuel handling system provides controlled and stable fuel delivery to the furnace, supporting variable biomass quality and uninterrupted operation.

Moving Grate Biomass Furnace – 18 MW
The moving grate furnace forms the core of the combustion system, delivering efficient and complete burnout of wood biomass. The grate design allows gradual fuel movement, stable combustion, and effective ash discharge, even under fluctuating load conditions.

3-Pass Hot Water Boiler – 15 MW
A 3-pass hot water boiler is installed downstream of the furnace, designed for high heat transfer efficiency, low flue gas temperatures, and long service life. The boiler supplies hot water to the district heating network at the required operating parameters.

Two-Stage Flue Gas Treatment and Heat Recovery
The flue gas line incorporates a two-stage cleaning and heat recovery concept. High-efficiency dust removal is combined with advanced thermal energy extraction, significantly increasing overall plant efficiency.

SNCR System with Urea Reagent
Selective Non-Catalytic Reduction (SNCR) technology is implemented to reduce NOₓ emissions. Urea injection into the furnace ensures compliance with stringent environmental regulations while maintaining operational simplicity.

Two-Stage Flue Gas Condensers
The flue gas condensers recover both sensible and latent heat from the exhaust gases, boosting the plant’s total thermal output and substantially improving fuel utilisation.

Absorption Heat Pump (AHP)
An absorption heat pump further upgrades low-temperature heat recovered from flue gas condensation, allowing additional energy to be fed into the district heating system and maximising seasonal efficiency.

Ash Handling and Discharge System
Automatic ash extraction and conveying systems ensure clean operation, reliable residue removal, and simplified maintenance routines.

Automation and Control System
The entire boiler house operates under an advanced automation system, providing process control, performance optimisation, emissions monitoring, and safety management. This enables stable, efficient, and largely unmanned operation.

This project stands as a reference example of a high-efficiency, low-emission, turn-key biomass district heating plant, combining proven combustion technology with advanced heat recovery solutions to maximise renewable energy utilisation.