A new life is being sought for Estonian oil shale waste

22.09.2025
A new life is being sought for Estonian oil shale waste. 22.09.2025. Estonia’s oil shale – kukersite – has for decades been the country’s main energy source. It has been burned in power plants and used in oil production. However, direct combustion no longer meets environmental standards, and oil production doesn’t extract the full value from the resource. At the same time, EU strategic documents emphasize that access to critical raw materials is increasingly important for the green and digital transitions and for economic resilience. Fragrances from kukersite TalTech’s Industrial Chemistry Lab (TKL) was established in 2017. In cooperation with the company Kerogen OÜ, projects Kerox I–III were launched. The most recent, Kerox III, was awarded TalTech’s Development Project of the Year in 2024. It resulted in a technology that enables kukersite to be converted—without intermediate steps such as oil or energy production—into valuable chemical compounds: aliphatic dicarboxylic acids. This significantly shortened process reduces environmental impact and improves product competitiveness across various industries. While the Kerox project focused on aliphatic acids, the TemTa project, launched in 2024 under a thematic research and development program initiated by the Estonian Research Council and co-funded by the European Union and the Estonian government, expands the scope. It is now exploring how to derive aromatic carboxylic acids—highly valued raw materials in the chemical industry—from kukersite. One of the targets is 3,5-dimethoxytoluene, a fragrance ingredient that could be produced from kukersite through just a few processing steps. Another major goal is to find uses for waste from the oil shale industry. At current mining levels, nearly six million tons of waste rock are generated annually—about half a ton for every ton mined. Most of it is landfilled. However, studies show that kerogen found in deposited waste rock could be used to produce base chemicals. This means that instead of extracting raw materials from new deposits, the chemical industry could rely on existing waste. As a result, comparable economic output could be achieved with significantly less resource consumption. Europe with less dependency The aim of the project is to develop chemical transformations and technological solutions that enable more efficient conversion of kerogens from various sources and better utilization of mineral resources. The knowledge gained also contributes to research on phosphorite and metal ores, which generally don’t focus on oil shale layers. A renewed perspective on the potential of waste rock would allow oil shale to be valorized as a byproduct, thereby supporting the circular economy principle: one industry’s waste becomes another’s raw material. The results would extend beyond Estonia—oil shale is more widespread than oil or coal, and its processing residues can be found from China to Brazil. The plan is to establish a new, modern, and sustainable branch of the chemical industry in Estonia, which would reduce Europe’s dependence on imported chemicals. The potential products could be used in polymers, construction foams, pharmaceuticals and cosmetics, and lubricant additives. This would lower the EU’s import needs and raise the profile of Estonia’s chemical industry. The project aligns with the goals of the European Green Deal and Estonia’s oil shale strategy and could provide strong momentum for a knowledge-based industrial sector. The project “Sustainable Valorization of Organic Components of Estonian Mineral Resources and Secondary Raw Materials into Chemicals” (TEM-TA128, 1.04.2024–31.12.2028) is co-funded by the European Union and the Ministry of Education and Research.
TalTech senior researcher Kristiina Kaldas is exploring ways to utilize oil shale waste and develop a more sustainable chemical industry. Photo: TalTech

TalTech senior researcher Kristiina Kaldas is exploring ways to utilize oil shale waste and develop a more sustainable chemical industry. Photo: TalTech

Under the leadership of Kristiina Kaldas, senior researcher at the Department of Chemistry and Biotechnology at Tallinn University of Technology, efforts are underway to give new life to oil shale industry waste and to develop a more sustainable chemical industry.

Estonia’s oil shale – kukersite – has for decades been the country’s main energy source. It has been burned in power plants and used in oil production. However, direct combustion no longer meets environmental standards, and oil production doesn’t extract the full value from the resource. At the same time, EU strategic documents emphasize that access to critical raw materials is increasingly important for the green and digital transitions and for economic resilience.

Fragrances from kukersite

TalTech’s Industrial Chemistry Lab (TKL) was established in 2017. In cooperation with the company Kerogen OÜ, projects Kerox I–III were launched. The most recent, Kerox III, was awarded TalTech’s Development Project of the Year in 2024. It resulted in a technology that enables kukersite to be converted—without intermediate steps such as oil or energy production—into valuable chemical compounds: aliphatic dicarboxylic acids.

This significantly shortened process reduces environmental impact and improves product competitiveness across various industries.

While the Kerox project focused on aliphatic acids, the TemTa project, launched in 2024 under a thematic research and development program initiated by the Estonian Research Council and co-funded by the European Union and the Estonian government, expands the scope. It is now exploring how to derive aromatic carboxylic acids—highly valued raw materials in the chemical industry—from kukersite. One of the targets is 3,5-dimethoxytoluene, a fragrance ingredient that could be produced from kukersite through just a few processing steps.

Another major goal is to find uses for waste from the oil shale industry. At current mining levels, nearly six million tons of waste rock are generated annually—about half a ton for every ton mined. Most of it is landfilled. However, studies show that kerogen found in deposited waste rock could be used to produce base chemicals.

This means that instead of extracting raw materials from new deposits, the chemical industry could rely on existing waste. As a result, comparable economic output could be achieved with significantly less resource consumption.

The industrial chemistry group researching oil shale valorization at TalTech’s Industrial Chemistry Lab. Photo: TalTech

The industrial chemistry group researching oil shale valorization at TalTech’s Industrial Chemistry Lab. Photo: TalTech

Europe with less dependency

The aim of the project is to develop chemical transformations and technological solutions that enable more efficient conversion of kerogens from various sources and better utilization of mineral resources. The knowledge gained also contributes to research on phosphorite and metal ores, which generally don’t focus on oil shale layers. A renewed perspective on the potential of waste rock would allow oil shale to be valorized as a byproduct, thereby supporting the circular economy principle: one industry’s waste becomes another’s raw material.

The results would extend beyond Estonia—oil shale is more widespread than oil or coal, and its processing residues can be found from China to Brazil.

The plan is to establish a new, modern, and sustainable branch of the chemical industry in Estonia, which would reduce Europe’s dependence on imported chemicals. The potential products could be used in polymers, construction foams, pharmaceuticals and cosmetics, and lubricant additives.

This would lower the EU’s import needs and raise the profile of Estonia’s chemical industry. The project aligns with the goals of the European Green Deal and Estonia’s oil shale strategy and could provide strong momentum for a knowledge-based industrial sector.

The project “Sustainable Valorization of Organic Components of Estonian Mineral Resources and Secondary Raw Materials into Chemicals” (TEM-TA128, 1.04.2024–31.12.2028) is co-funded by the European Union and the Ministry of Education and Research.