Forestry by-products previously used for energy production are increasingly being processed into products with higher added value. If we take the most optimistic future scenario, as the possibilities for using forestry products increase, the electrical capacity required to be sourced from other supplies could be equivalent to the output of approximately three standard nuclear power plants.
Only about half of the wood used in pulp production ends up as the desired final product, with the rest being burned to generate energy. Part of this renewable energy is used within the mill itself, and the surplus is sold as heat to local district heating networks and as electricity to the national grid.
It is important to remember a strict requirement: the forestry sector must produce goods that ensure longer-term carbon storage, as the carbon stored in wood is immediately released into the atmosphere during energy production. A second driving force behind these processes is the market: the more (“further”) a raw material is processed, the higher its price.
The European Forest Institute (EFI) and ETLA Economic Research (Etla) have jointly conducted a study titled FutureForest 2040, concluding that the most optimistic scenario for forestry product development will reduce energy production from forest products by an amount equivalent to the capacity of three or even five nuclear power plants (for example, the capacity of Finland's newest nuclear power plant, Olkiluoto 3, which is 1600 MW). Correspondingly, there will be an increase in demand for energy, which is undoubtedly necessary for the production of more modern wood-based products.
Developing new products in the forestry sector is the main task of Professor Ali Harlin (Ali Harlin) of the VTT Technical Research Centre of Finland. He believes that the estimates in the aforementioned study are sufficiently realistic. "I would say that covering the energy deficit will require approximately three times the capacity of Olkiluoto 3," reckons A. Harlin.
Many products based on bioplastics are already available
One by-product of pulp production is tall oil, which can be not only burned but also processed into renewable fuel, which in turn is an important component of Finland's climate strategy regarding road transport. This is linked to the requirement for the mandatory replacement of a specific portion of fossil fuels with renewable fuel. In Finland, renewable transport fuels are produced by UPM and Neste.
According to A. Harlin, forest industry companies such as UPM do not produce renewable diesel solely for sale. “This is clearly a product development project,” explains A. Harlin.
Thanks to specific regulations (such as distribution mandates), there is a stable market for diesel, and sales revenue allows for further product development.
“The formula is as follows: diesel is sold for one dollar per litre, whereas oil products are sold for five dollars,” explains A. Harlin. Furthermore, every litre of a highly processed product means that one litre less of oil is burned as transport fuel.
For example, the UPM biorefinery in Lappeenranta, eastern Finland, produces renewable diesel used as transport fuel, while bio-naphtha derived from tall oil can be used as a biocomponent for petrol and as a raw material for the production of various types of plastics, such as polypropylene, polyethylene, and polyvinyl chloride (PVC).
Plastics made from bio-naphtha can be used in various ways, for example, as polyethylene coating for milk cartons from the dairy company Arla, protective gloves from Jokasafe, moisturiser jars for the cosmetics company Lumene, Dyneema ropes, and Tarkett floor tiles.
Materials made from UPM BioVerno naphtha are also used for automotive interiors, raincoats, and carpets. UPM uses it to produce Raflatac Forest Film adhesive tape and UPM Formi EcoAce biocomposite, which in turn is used by the sparkling water manufacturer Mysoda Woody.
Biomaterial cannot meet all demand
According to Ali Harlin, it makes no sense to use all extractives to produce other raw materials, as pulp production processes also require energy. “The production process of pulp mills requires four-fifths of the energy contained in the extractives,” says A. Harlin.
In addition to using extractives in the production of diesel and lignin, the forest industry is well aware of how to separate lignin from them. In fact, lignin could become a primary product instead of pulp. It is also used in the production of carbon fibres; Ali Harlin also mentions the use of lignin in concrete (as a plasticiser). “The more plastic the concrete is, the easier it is to pour. An additional advantage, thanks to lignin, is that concrete can bind more non-fossil carbon,” explains A. Harlin.
Lignin has long been used in the production of wood adhesives, although their market, even internationally, is very small. “Another use is carbon products, such as battery materials and carbon fibres. None of these can be produced in large quantities, but what is produced increases revenue quite well,” emphasises A. Harlin.
Metsä Group reports that its Kemi bioproduct mill, upon completion of construction work, will increase the production of biochemicals, including tall oil and turpentine, by 50,000 tonnes per year. As is known, tall oil and turpentine are by-products used to manufacture other high-added-value products.
Ali Harlin points out that the use of biomass will not be a silver bullet that will resolve all the climate problems caused by the disproportionate use of fossil resources.
“The volume of biomass that can be obtained at a reasonable cost will not be large,” he emphasises. Global biomass production is not sufficient, particularly to meet the demand for energy. “Biomaterials should be used in the manufacture of high-performance products, because their production will always be expensive,” concludes A. Harlin.