Waste-to-energyExplore how Gren transforms waste into energy that supports local communities and reduces landfill.
Explore how Gren transforms waste into energy that supports local communities and reduces landfill.
Turning waste into a valuable resource
Bottom ash reuse
Leading the circular transition
Gren Lietuva is pioneering the reuse of bottom ash – a by-product of non-hazardous waste-to-energy processes – as a sustainable and locally available construction material.
This initiative supports Lithuania’s transition to a circular economy, where nothing goes to waste and every material finds a new purpose.
Building the future
Through research, innovation, and partnership, Gren proves that circular solutions are not just a vision – they are already shaping Lithuania’s infrastructure today.
With every kilometre of road and every bike path built, Gren is transforming waste into value and helping create a cleaner, more sustainable future for everyone.
1 million
tonnes of waste transformed into valuable construction material
248,000
tonnes of bottom ash reused
Environmental benefits
Reusing bottom ash delivers measurable benefits:
- Reduces landfill waste and CO₂ emissions
- Lowers the demand for extracted natural materials
- Promotes local, sustainable material use
- Contributes to national circular economy and climate goals
Gren’s bottom ash complies with strict environmental criteria: metal content ≤5%, organic carbon ≤3%, ignition loss ≤6%, and controlled leaching values. Before reuse, the material is conditioned for approximately three months to ensure stability and environmental safety.
From energy recovery to infrastructure
Each year, the Gren Klaipėda plant processes non-recyclable waste to generate clean energy for homes and businesses. About 25% of this waste becomes bottom ash, which Gren prepares for reuse instead of disposal.
Between 2021 and 2025, Gren has reused approximately 248,000 tonnes of bottom ash, equivalent to nearly 1 million tonnes of waste processed through circular use. What once would have gone to landfills is now the foundation of Lithuania’s roads, bike paths, and industrial sites.
Projects across Lithuania
Gren’s bottom ash has been successfully used in multiple infrastructure projects, including:
- Jurbarkas (2021) – Lithuania’s first pilot road section (9,000 tonnes).
- Dumpiai (2021) – processing and site development (21,900 tonnes).
- Vėžaičiai, Tauragė, Pagėgiai, Šilutė (2022) – platform and road foundation construction.
- Klaipėda (2024) – Lithuania’s first urban bike path built with bottom ash.
These projects demonstrate how circular materials can safely and effectively replace imported natural aggregates, reducing both environmental impact and material costs.
Science and recognition
Gren collaborates closely with the VILNIUS TECH Road Research Institute, whose studies have confirmed that bottom ash meets all environmental and engineering requirements for use in unbound road base layers.
This innovation was recognised with the 2024 Baltic Road Award for Scientific Innovation, acknowledging Lithuania’s leadership in applying circular economy principles to road engineering.
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Waste-to-energy
