Dennis Williams | Commercial Director | Associated Energy Services (AES) | mail me |
Pressure is mounting for local manufacturers to replace fossil fuels with biomass. They need to reduce their carbon footprints and mitigate carbon taxes. Switching to biomass power is one of the key pathways under discussion.
Market requirements and the drive to switch to biomass are growing. In practice, however, adoption is not as prolific as many believe.
The exception to the rule
Currently in South Africa, biomass is mostly used for own-energy generation. Sugar mills use bagasse and sawmills use timber residues. Industrial thermal energy applications, such as steam, remain the exception. Despite this, over 10% of our current client base uses biomass for steam generation.
Interest in alternative fuels such as biomass is also growing among another 20 to 30% of clients. Switching to biomass power could unlock significant opportunities for this group.
Multinationals with stringent global carbon reduction targets face the most pressure to change. Food manufacturers supplying sustainability-conscious retailers also face this pressure. These multinationals often assume decarbonisation in South Africa is as easy as in other regions. That is not the case. South Africa has a constrained energy mix and relatively cheap coal.
Every user aims to access gigajoules of energy with a consistent and repeatable fuel specification. This allows them to select suitable technology, maximise efficiency and achieve the lowest possible steam cost.
Each biomass type has different technical characteristics. In general, biomass has low energy and bulk density. Moisture content reduces the realisable calorific value of the fuel. Particle size and processing must match a suitable combustion system, which is a critical consideration.
In some cases, silica entrained within the biomass complicates ash clinkering and combustion. In agricultural biomass, ash chemical composition can cause slagging or fouling in heat transfer systems. Designers must accommodate this in combustion or boiler system planning.
Innovative integration
Retrofitting existing energy plants is possible. This usually involves re-using the boiler heat exchange component of the steam plant and adding a combustion system suited to the fuel. Examples include gasifiers or Dutch ovens with step grates.
New technologies are also emerging. These include bio-digesters with Combined Heat and Power(CHP) plants and waste heat recovery. Gasification and pyrolysis solutions are additional options. With proper heat recovery, these systems can generate usable steam on the back end.
Companies must also consider more than capital investment. They need storage space and logistics for transporting biomass, which is often bulky.
The biggest impact, however, comes from the cost of technology change. A new boiler system is usually required. The main benefit is that CO2 emissions from biomass combustion are deemed carbon-neutral. This creates a substantial carbon footprint and carbon tax benefit compared with fossil fuels. Switching to biomass power therefore offers both environmental and economic advantages.
Stand-out steam success stories
Despite challenges, several clients have achieved notable successes with biomass for thermal energy needs:
- A FMCG client has used a state-of-the-art Belgian biomass boiler for over 10 years. The unit provides 6 to 8% higher efficiency compared with lower-cost waste heat boilers. However, it costs about 40% more in capital. While operational costs increased, the plant met decarbonisation requirements.
- A dairy client introduced a biomass boiler to reduce fuel oil usage. They saw a substantial drop in their carbon footprint and will benefit from significantly reduced carbon tax liabilities.
- A food manufacturer installed a biomass hot water solution to offset liquid fuels. The plant has run for 18 months and ties to a planned production expansion. This project will reduce operating costs while greening the overall energy mix.
The future of biomass
Companies considering biomass should partner with an experienced service provider. The provider should be technology- and fuel-agnostic, with proven project execution and operations expertise. Companies must also remain open-minded, clear about their goals, and willing to act decisively to make progress.
Reliable biomass supply is essential to prevent untenable cost escalations as more firms adopt this energy source. Typical biomass resources include timber and timber residues. Agricultural residues such as sunflower husks, corn cobs, peach or apricot pits, macadamia shells, straw and plant fibres are also viable.
Novel applications include using vegetation for land rehabilitation and cultivating energy crops. Some suppliers now formalise offerings to ensure quality, specification and cost consistency. As traditional options like timber residue get absorbed, new alternatives will be required.
The process then repeats. Specifications must be defined, quality parameters set, suitable technologies identified and economics recalculated. Complexity increases as cheaper biomass options are absorbed first and later alternatives cost more.
