TNO boosts market opportunities for bio-based building materials made out of fibre

Bio-based building materials

The built environment is responsible for 38% of all CO2 emissions in the Netherlands¹, with 11% of this relating to materials. Using bio-based building materials reduces CO2 emissions in the short term, as far less CO2 is emitted during the production process than during that for fossil-based materials. There is also the added effect of keeping the carbon stored in the material for longer.

Both of these aspects are essential to make construction completely carbon-neutral by 2050. Wood is the best-known and most widely used bio-based building material, currently accounting for 2% (by weight) of materials in the Dutch construction industry. With other bio-based materials making up just 0.1%, there is still plenty of potential for other raw materials to help boost that share.

New revenue models

Joost Vette specialises in developing building materials out of fibres at TNO. ‘Fibre crops such as hemp, straw, and flax are crucial for the Netherlands to produce substantial volumes of bio-based materials. As we don’t have large forests here, we have little wood of our own – but thanks to our prominent agriculture and horticulture sectors, we’re global leaders in the efficient production of biomass.’

‘The ‘Nationale Aanpak Biobsed bouwen’ programme encourages farmers to produce biomass for the construction industry. Supplying residual waste as a source for bio-based building materials could be an additional source of income for horticulture businesses. I’m convinced that bio-based developments will lead to new revenue models for biomass in the Netherlands, so we’ll be able to achieve our climate targets while still meeting our economic objectives.’

Producing board materials from bell pepper plants

Besides primary agricultural crops such as straw, hemp, and flax, waste streams can also be harnessed to produce board and insulation materials using fibres.

‘There are plenty of agriculture and horticulture businesses that produce waste streams and would happily explore how they can play their part in the circular economy,’ Vette says. ‘These include horticulturalists and growers from the Westland region, but also government agencies such as Water Boards and municipalities that could supply cuttings from maintaining their green spaces.’

‘One particular raw material that we are currently studying is the bell pepper plant – a promising source of fibre simply because of how common it is, Vette notes. ‘The Netherlands produces around 50,000 tonnes of residual waste from tomato and bell pepper plants every year. At TNO, we’re currently researching ways to use these fibres in construction materials.’

Binderless pressing

Vette has not chosen the easiest material to work with. ‘The easiest way to stick pieces of wood together is to glue them, but there are substances in some raw materials that can act as a binder, doing away with the need for glue. Bell pepper plant fibres contain lignin, which – under the right conditions – can be extracted to stick the fibres together again. We call this binderless pressing.’

With the right pre-processing, this involves pressing the boards together using either high pressure or a high temperature, without adding any binder. ‘We’re looking at which method yields the best results. For example, steaming the fibres first makes them open up more.’

On top of binderless pressing, we are also working with partners to investigate the use of bio-based adhesives, which may be suitable for certain types of board material.

Building up the market

Ambitious start-ups are working hard on developing promising new building materials made out of fibre crops. However, Vette notes that little progress has been made in building up the market. ‘There’s no shortage of innovative power in the Netherlands when it comes to entrepreneurs who want to help the construction sector go carbon-neutral, but many of them lack access to capital or specific knowledge they need to produce new materials in larger volumes, which is essential for parties in the construction industry to gain experience in using them on the job.’

‘I know this from my own experience: before joining TNO, I had my own bio-based start-up, Fairm, that developed insulation material using mycelium as a binder. It was a promising product, but unfortunately it never moved past the scaling-up phase.’

Working together on scalable solutions

Through TNO BioBuilt we are looking to work with parties both large and small to bring promising developments to fruition.

Vette: ‘With TNO BioBuilt, we want to offer market parties an accessible innovation centre where we can jointly develop both products and production processes until they’re ready to be deployed in the field. We offer a processing site for reclaimed timber, as well as a small-scale production facility for cross-laminated timber (CLT) and bio-based board and insulation materials made out of fibre crops. Ideally, we want to combine these techniques to create promising new bio-based materials.’

‘We’re also capable of generating prototypes for use in pilot projects. Finally, we’re using the production lines to map out processes, calculate their environmental impact, and extensively industrialise and potentially automate them.’

Also want to collaborate in TNO BioBuilt?

Together with market parties, Vette wants to continue working on various techniques at the BBMIC until a promising product is ultimately created that can be used in construction. ‘Ideally, we want these bio-based variants to become a fully-fledged alternative to common chipboard and fibreboard like OSB and MDF, because those are used in large volumes. Another promising product is hybrid CLT, for which fibre streams can be used. But we’re not there just yet.’

Vette expects TNO BioBuiltto play a prominent role in scaling up these kinds of innovative applications. ‘At TNO, we have a unique combination of expertise on materials, construction processes, and certifications. Our partners at BioBuilt have easy access to that knowledge, helping them to develop products that work faster.’