Green Transition

From useless plastic waste to valuable oil

Researchers and business people have developed a new technology that can make oil from plastic waste that cannot be recycled. This oil can be used to make new plastic and other oil-based products. The technology was recently utilized in a new commercial facility in West Zealand, Denmark.

The research project RePlastic has focused on using pyrolysis for the chemical recycling of dirty and mixed plastic waste. Illustrator Benny Box.
Caption: Pyrolysis can transform plastic waste into an oil that can be used as an additive in the petrochemical industry where it can replace new crude oil.

From test reactor to industrial facility 

When RePlastic launched in January 2020, the goal was to form the basis for a technological solution that could be commercialized within a few years for the benefit of the green transition. The aim was to attract investors for the primary project partner, Waste Plastic Upcycling (WPU), which specializes in converting plastic waste into different types of oil that the industry can use in the production of new products.

Things have been moving really fast since then, because the technology is scalable and there is a demand for new technologies that can handle the different fractions of our plastic waste. Already during the research project, WPU has found investors, built an industrial pyrolysis facility, and hired employees. 

“We’re experiencing a lot of interest in robust and financially attractive technologies such as WPU’s, both nationally and internationally. The fact that plastic waste doesn’t have to be treated before the pyrolysis process with us makes a big difference, both financially and in relation to the assessment of potential environmental impacts and resource consumption,” says Niels Bagge, CEO of WPU.

Because the pyrolysis technology minimizes the resource-intensive sorting and purification, the is a great potential for making the process more sustainable. However, exactly what role pyrolysis technology will play in our waste system in the future depends on many factors.

“Pyrolysis technology definitely has potential in terms of recycling some of the more difficult plastic waste. In the future, we need to make sure to take into account both the choice of materials in products, the management and processing of waste in the waste system, and reusing it for new raw materials for industries. Using pyrolysis for mixed plastic fractions can play an important role in the plastic cycle,” says former DTU Professor Thomas Fruergaard Astrup, who assessed the sustainability of plastic recycling and pyrolysis technology in the RePlastic project.


One method for chemically recycling plastic is pyrolysis. The word pyrolysis comes from the Greek words for "fire" (pyro) and "to split" (lysis).

In pyrolysis, the plastic waste is heated to high temperatures in an oxygen-poor environment, resulting in gasification. The gas is then condensed into pyrolysis oil. Without oxygen, the plastic will not burn. Pyrolysis is already being used to chemically transform materials such as wood into charcoal or agricultural waste into fuel.

The resulting pyrolysis oil can be used as an additive in new plastic products or as a sustainable addition to fuel. Thus, it has the potential to supplement or replace fossil oil or bio-oils made on agricultural land.


RePlastic—Thermal recycling of plastic waste reject—works with less pure plastic types that cannot be recycled mechanically. 

RePlastic is a collaboration project between two universities, DTU and Roskilde University, and five industrial partners. The research project is headed by DTU Chemical Engineering and has a total budget of DKK 12.7 million, of which 8.9 million was granted by Innovation Fund Denmark.

The primary business partner is Waste Plastic Upcycling (WPU), which specializes in converting plastic waste into different types of oil that the industry can use for the production of new products.


Funding: Innovation Fund Denmark

Duration: 3 years (01/04/2020 – 31/03/2023)