ifeu study: More targeted use of renewable raw materials

The bioeconomy can be a central building block for the transformation of our largely coal, oil and gas-based economy. However, renewable raw materials and synthetic carbon compounds are scarce and expensive. They should be used in areas such as the chemical industry - not as energy sources. For the shift from a fossil-based economy to a bioeconomy to succeed, fossil carbon must also become more expensive. The ifeu now presents the results of four trend-setting studies.

"Carbon compounds will continue to be needed in the chemical industry and, in the medium term, in parts of the transport sector. Here we can use biomass and other renewable carbon sources for chemicals, bio-based products or fuels, replacing fossil carbon in the form of oil and gas," says ifeu project manager Dr Heiko Keller. "Bioeconomy provides much more than fuels from agricultural biomass," adds Nils Rettenmaier, also project manager and expert on
Biomass and Bioeconomy at ifeu. However, the resources of the bioeconomy are a scarce commodity. Cultivation areas for renewable raw materials are limited by food production and the protection of biodiversity.

Such cultivated biomass can no more cover the long-term demand for carbon than can biogenic residues. Defossilisation of the economy needs framework conditions. In order to build a stable market, the bioeconomy would need fair competitive conditions in which its advantages over products made from
fossil CO2 sources are taken into account, according to the experts. Thus, in the long term, products from biogenic raw materials can prevail over the hitherto cheaper fossil raw materials through a higher CO2 tax. In addition, sufficient green electricity and hydrogen must be available in the medium term.

"If the right course is set, the bioeconomy can make a significant contribution to defossilisation," says Rettenmaier. "It is an important piece of the puzzle in the transformation towards a climate-friendly society.

For large parts of the economy, ways to say goodbye to fossil fuels are now foreseeable - for example with electric cars and heat pumps instead of combustion engines and gas heating. But a complete decarbonisation of the economic system is neither possible nor sensible. Therefore, ifeu is researching technologies that make sustainable renewable carbon available. The reports from four recently completed large-scale projects provide valuable new insights.

(Re)activating arable land that is hardly usable for other purposes
In the EU, there is a lot of unused arable land and some special sites such as post-mining areas. With the cultivation of frugal biomass on these so-called marginal areas, the increasing competition for land use can be mitigated. In the MAGIC project, ifeu has identified boundary conditions that must be met for sustainable implementation:
- Care must be taken not to endanger biodiversity, which can be high on parts of these areas, through use.
- Imposing conditions on subsidies that are necessary anyway can be a solution to this conflict of goals.

Detailed recommendations can be found in the report on MAGIC at
https://www.ifeu.de/projekt/magic

Converting biomass residues into products needed in the long term
Many residual materials such as straw or green waste from landscape conservation (so-called lignocellulosic residues) are not used to a large extent. Others, such as forest residues, are currently burned primarily for energy use. However, heat can and should be generated in the medium term, for example via heat pumps using green electricity. The scarce renewable carbon is too precious for these decarbonisable applications. New technologies are now being developed so that these residues can be efficiently converted into products such as chemicals or aviation fuel in the future.

The UNRAVEL project investigated how new processes and value chains for chemicals and building materials (insulating foam boards, bitumen sealing membranes, etc.) can be established. From a sustainability point of view, decisive progress was made:

- The process can now flexibly use different residual materials at constant product quality - depending on sustainable availability.
- The energy efficiency of the main process (organosolv) was significantly increased.
- A technical bottleneck has been identified that has so far been responsible for the fact that residual materials that are currently hardly used in particular can be converted less efficiently.

Concrete further steps on how the process could be further developed in a future-proof manner, both from a raw material and product perspective, are listed in the reports (link: https://www.ifeu.de/projekt/unravel).
Lignocellulosic residues can also serve as a feedstock for bio-oil by means of pyrolysis. A process developed in the BioMates project uses green hydrogen to prepare the bio-oil for easy feed into petroleum refineries. Partial replacement of petroleum in refineries with bio-oil can reduce greenhouse gas emissions in the relatively short term. This is urgently needed from a sustainability perspective. In the long term, the share of refinery products for chemicals, aviation and marine fuels in particular could be expanded. The sustainability assessment is available at https://www.ifeu.de/projekt/biomates available.
Synthetic hydrocarbons
In the eForFuel project, it was not biomass that was investigated as a carbon source, but the synthesis of hydrocarbons from CO2 from industrial point sources (here: blast furnace gas) as well as the air. This can be converted to formic acid in an electro-biorefinery using renewable electricity and water and fermented in a bioreactor with the help of microorganisms. The end products are synthetic fuels such as propane and isooctane. Main findings from this project:

- Renewable carbon can be obtained in far greater quantities if it comes from CO2 instead of plant biomass. However, even in this case, efficient use is crucial, because harnessing it requires a great deal of energy.
- Many improvement options could be identified. However, some development work is still needed before it is ready for the market.

Details and reports are available at https://www.ifeu.de/projekt/eforfuel available.

Source: ifeu-PM of 15.2.2023