Towards a climate neutral EU:
efficient allocation of EU funds

Solar Thermal District Heating Plant at Salaspils Siltums, Latvia

Organisation: Green Liberty Website: Added: June 22, 2022
Project start date: February 08, 2018
Project end date: January 07, 2020


Filter, in cooperation with Arcon-Sunmark A/S, delivered the largest solar thermal district heating plant in all of Eastern Europe. This award-winning feat of engineering resulted in a 1,720-panel solar field providing an annual output of 12,000 MWH, combined with a 3 MW biomass-based boiler. The main purpose was to reconstruct and convert a conventional district heating plant into a  modern, renewable energy-based district heating plant. The common problem of solar thermal energy-level fluctuations throughout the year has been solved with an 8,000-m3 accumulator tank that stores energy using glycol heat exchange. The previous systems have been integrated with the new installed technology and will serve as a backup heat source during maintenance works to ensure a steady and constant heat supply. The newly installed systems include a 3 MW biomass-based boiler that provides extra heating during winter time. All the additional heat sources have been integrated and synchronised with the existing heating network. This ambitious and successful project has received nationwide recognition for its feat of engineering, while the Salaspils Siltums district plant won the prestigious Latvian 'Grand Prix' construction award over 162 rival nominees. Having claimed the 'Largest and most significant project of the year' award, the winner receives year-round national media attention (Dienas Biznes,,, Source:

Financial data

Total costs: EUR 8,619,565. EU Cohesion Fund co-financing; EUR 2,700,555.



Monitoring and communication of project results by data sharing. Example: Salaspils Siltums' Solar News, a monthly publication.

Wider adoption of non-emission technologies in district heating to decrease the share of woody biomass.

Information sources

Websites & personal communication

Other info

European Climate Initiative (EUKI)
This project is part of the European Climate Initiative (EUKI). EUKI is a project financing instrument by the German Federal Ministry for Economic Affairs and Climate Action (BMWK). The EUKI competition for project ideas is implemented by the Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) GmbH. It is the overarching goal of the EUKI to foster climate cooperation within the European Union (EU) in order to mitigate greenhouse gas emissions.