Demand for biomass from power and heat generators as well as heavy manufacturing sectors — such as steel, cement, lime, sustainable aviation fuels and biofuels — is expected to increase significantly in the coming years, as these sectors seek alternatives to fossil fuels. Carbonised biomass, also referred to as torrefied pellets, has the potential to meet a large part of this increased demand, International Biomass Torrefaction Council (IBTC) president Michael Wild told Argus.
First, let us set the ground with regards to terminology — there are various terms used to describe what is widely referred by the industry as torrefied pellets. What is the difference between carbonised, torrefied, black pellets, biocarbon, biochar etc?
All the aforementioned names describe different stages along the carbonisation curve of biomass. A different term is used when the biomass is treated with a different level of devolatilisation.
Torrefaction for devolatilisation of 0-35pc follows Pyrolysis up to 70pc and above that biochar or biocarbon with up to 100pc devolatilisation. The demarcation is not clear and the industry is missing a clear definition. In the IBTC, we see the term "biocarbon" as the most inclusive expression, as all these processes have concentrated carbon in the solid product.
What are the key differences between white and black pellets? Does either have advantages over the other?
The actual term "black pellet" is an artificial and meaningless name that originally was invented by technology provider Zhilka for their brownish steam exploded products.
But there are key differences between densified thermally treated wood and untreated wood. The former has a higher net calorific value, increased energy density per tonne and per m3, can be made to measure to clients' wishes, has better grindability, better water resistance, an overall supply chain with a lower carbon footprint, and is more easily applied to a much broader spectrum of uses.
What is the current carbonised biomass production capacity — existing and planned or under construction? And where do you expect capacity to be in the coming three years (2025-27)?
I would say approximately 750,000-1mn t/yr of production capacity is currently active or in a commissioning phase. In the next 24 months I expect 500,000 t/yr of capacity to be added.
Numbers may increase in the future because of demand in not just the power sector, but the metallurgical industry, which is enormous and cannot be satisfied sufficiently with other types of biomass. For example, the new co-firing obligations in India and Indonesia mean that power plant operators explicitly demand torrefied products for technical reasons. But this is a 120mn t/yr market, and it will be more than a challenge to meet this demand sufficiently.
There was momentum for carbonised pellets about a decade ago, but most of the announced volumes did not materialise. What is different this time?
Momentum first came from carbonised biomass demand for co-firing in European power plants only. While torrefaction technology companies discovered more, the interest of the power utilities weakened, for political and other reasons.
The renaissance of torrefied biomass almost a decade later is characterised by the matured technologies that are available on an industrial scale. There is also much broader interest in the products, both geographically and by sector.
In which countries and regions is consumption of carbonised biomass concentrated? And what support is given to the sector in different regions?
Europe, Japan, the US, Canada and Brazil consume the most. We do not see a general difference in support between untreated and thermally-treated biomass in utilisation.
What are some of the challenges preventing certain industries from producing or using carbonised biomass?
Currently I am afraid that the production capacity on line is a limiting factor.
But having said so, I also should highlight that some of the consumers are themselves not completely clear about what product they want and can realistically be produced. So, a joint effort by consumers and producers' additional product standards needs to be developed.
How is carbonised biomass affected by the EU's revised renewable energy directive (RED III), or any other regional or national legislation?
Mostly the same as any other biomass. The only substantial difference is that through thermal treatment, a lot of the agricultural by-products that were not utilisable to date can be upgraded through torrefaction or carbonisation to fulfil requirements by consumers. In this respect, torrefaction can also help to mitigate the restrictive effect of some surprising political conditions put on the biomass sector.
Does South America have a role to play in the carbonised pellets market?
Absolutely. A crucial role on the one hand as a producer and exporter of carbonised biomass, but even more so as a consumer internally.
What is the difference between carbonised pellets and briquettes?
As a product the only difference is the shape. The chemical specifications of both products are identical.
The small pellets are relatively uniform while there is a wide variety of production techniques and shapes of briquettes — extruder, roller presses, piston press-cylinders, pillows, octagons, oval balls, etc. In general, briquetting consumes less power per output unit than pelletising. And since the biocarbon is so easy to grind, almost all consumers can handle briquettes just as well as pellets. In this respect, the lower production costs of briquettes are an advantage.
