Forestry waste turned into transport fuels and chemicals

VTT Technical Research Centre of Finland has developed a new technique based on gasification, which offers a sustainable way to turn forest industry by-products — such as bark, sawdust and forestry waste — into transport fuels and chemicals. The technique is said to reduce carbon dioxide emissions by approximately 90% compared to fossil fuels.

The new approach uses gasification to turn biomass into intermediate products — liquid hydrocarbons, methanol or methane — in production units integrated with communal district heating plants or forest industry power plants. The intermediate products are processed further in oil refineries to make renewable fuels or chemicals.

According to the International Energy Agency, modern bioenergy plays a key role in building a cleaner and more sustainable energy system. Bioenergy is needed, in particular, for reducing emissions from air transport and shipping and as a backup fuel for road transport as more electric cars are introduced. The use of forest industry by-products as raw materials does not impact on the carbon sink effect of forests, and they do not compete against forest industry raw material procurement or food production.

VTT developed and piloted the new gasification process and evaluated the competitiveness of plants based on the technique in the course of a recently concluded project called BTL2030. The distributed generation process developed by the project team makes efficient use of the energy content of biomass. Approximately 55% of the energy content is turned into transport fuels and a further 20–25% can be used to provide district heating or to produce steam for industrial processes.

The process is based on VTT’s low-pressure, low-temperature steam gasification technology, simplified gas purification and small-scale industrial syntheses. Thanks to the small-scale approach, the heat generated by the process can be used throughout the year, and the process can be fuelled with local waste. The small scale has also made it easier for VTT to secure funding for its first plant.

The BTL2030 project team estimates that the production costs of transport fuels made from domestic waste would amount to €0.8–1 per litre of petrol or diesel. The technology is set to become considerably more competitive as the costs of the raw materials of competing technologies increase, and the process is expected to be highly competitive at least from the year 2030 onwards. Even in the short term, the ultimate competitiveness of the technique hinges on the prices of crude oil and carbon dioxide quotas as well as the taxation of renewable transport fuels.

In addition to transport fuels, the biomass gasification technique can be used to produce renewable raw materials to replace oil and natural gas in various chemical industry processes. Synthesis gas applications, on the other hand, could help in the attainment of several circular economy goals, such as close-loop recycling of plastics and other packaging materials.

The development of gasification technology is set to continue through two EU Horizon 2020 projects coordinated by VTT. The projects focus on gas purification and increasing the efficiency of synthesis technology and aim to demonstrate the performance of the entire biofuel chain at VTT’s Bioruukki piloting centre in Espoo, Finland. Another solution under development is a flexible hybrid process based on biomass and solar and wind energy, which can either be run on just biomass or be boosted with electrolysis. This provides an efficient way to store solar or wind energy as a renewable fuel and could as much as double the renewable fuel output of the biomass sources available.

Image caption: The development of gasification technology takes place in VTT's Bioruukki piloting centre in Espoo, Finland. Image credit: VTT.

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