World’s largest pit thermal storage in Vojens
In Vojens, Denmark, a 200,000 m³ pit thermal storage basin stores surplus solar heat from a 70,000 m² collector field. Using Solmax geosynthetics, the system reduces CO₂ emissions by 6,000 tons annually.

Bornhausen Landfill is in Seesen, a town in the district of Goslar, in Lower Saxony, Germany.
Solmax installed 150,000 m² (1.6 million ft²) of geosynthetics as part Kreiswirtschaftsbetriebe KWB Goslar’s groundwater protection landfill project. The landfill is Class II covering an area of 7.5 hectares with a gradient of up to 1:3. This geosynthetic layer helps to protect the surrounding environment. Waterproofing work began in March 2021 and was completed in June 2022.
The landfill is situated in the Harz Mountains, which experiences unpredictable and sudden rain showers that made the installation difficult. The geography of the area is also challenging because of long, steep slopes up to 120 m (394 ft) long. The installation team needed to work efficiently to make sure the geomembranes were not installed during rain.
Despite the unfavorable weather conditions and geometry, a total of 150,000 m² (1.6 million ft²) of geosynthetics were laid on the construction site in 2021.
Solmax supplied and installed GSE® HD with BAM-certification, 2,5 mm (1 mil) and FABRINET® with BAM-certification, which provides increased durability for filtration and drainage, and is suitable for a variety of field conditions and thickness requirements. The installation team consisted of one senior welding technician and two welding technicians plus additional helpers.

BORNHAUSEN LANDFILL, GERMANY

BORNHAUSEN LANDFILL, GERMANY
World’s largest pit thermal storage in Vojens
In Vojens, Denmark, a 200,000 m³ pit thermal storage basin stores surplus solar heat from a 70,000 m² collector field. Using Solmax geosynthetics, the system reduces CO₂ emissions by 6,000 tons annually.
Pit thermal energy storage in Gram, Denmark
In Gram, Denmark, a 122,000 m³ pit thermal energy storage with a 44,800 m² solar collector field provides 18,000 MWh of heat annually. Solmax geosynthetics ensure safe high-temperature storage and reduce CO₂ emissions by 3,700 tons per year.
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