Making silk purses from hog fuels: A Golden Opportunity to Add Value via new solid biofuels standards : Biofuels Digest


By Patrick Olivier BSc. Forestry, MBA, Lee Enterprises Consulting Inc.

Special to The Digest

In 2015, the Canadian Standards Association adopted and published a series of CAN/CSA – ISO 17225 Solid Biofuels Standards based on the harmonization of European and ISO standards.  The objective of the series, as stated in the ISO Standard, is “to provide unambiguous and clear classification principles for solid biofuels and to serve as a tool to enable efficient trading of biofuels, enable good understanding between seller and buyer, and for communication with equipment manufacturers”.  In the USA an initiative is underway to develop a national woodchip standard.

A value-add

A broad industry adoption of these standards could revolutionize the forest biomass supply chain converting biomass from a low grade, low cost commodity to a highly differentiated added value product.  Think about the status quo in the forest industry in most of North America today.  A buyer specifies the purchase of ‘hog fuel’ measured by weight with scant regard for quality other than some contractual, loosely defined restraints to provide ‘chips’ free of dirt or tramp metal for a limited term and at some local market driven price point.  Under these circumstances, the seller’s incentive is to maximize the weight in every form possible and let the seller do the hard work of processing the ‘hog fuel’ turning it into a consistent feedstock suitable for the plant.  After all, ‘hog fuel’ is often considered to be at the bottom of the barrel in terms of what is recoverable from the tree, with no further value to be extracted, and it usually contains everything that has been left behind once the good wood has been removed.

These new standards would suggest otherwise.  As we have learned from past experience, not least from the lumber industry where grading systems have been applied, the overall average price of the commodity graded by specified quality attributes is always higher than a straight ‘mill run’ grade.  How might this play out in the biomass supply chain and market place?

Lowest hanging fruit

The lowest hanging fruit is to be had by drying biofuel.  Consider the quality attribute of moisture content. CAN/CSA-ISO 17225-4 together with CAN/CSA-ISO 18134 1, 2, & 3 provide standardized methodologies and test procedures for the determination of moisture content. The adoption of these standards will provide satisfaction to both buyer and seller.  Lower moisture content should translate to higher prices for the seller for most applications – combustion, gasification, CHP, wood pellets, and most bio-liquids.  A seller who is able to dry the fibre either passively through seasoning in roundwood form, or actively through the introduction of biomass dryers, should be able to make the business case for the cost for the improvement with the resulting return on investment.  The buyer, in turn, is guaranteed a consistent product resulting in higher efficiencies and better control of emissions.  And everyone benefits from the lower transportation costs as the movement of water is eliminated from the equation.

An interesting quality attribute is in the specification of ash content.  A buyer wishing to minimize ash disposal and meet environmental refuse and landfill regulations has a way of achieving this through specification within the CAN/CSA-ISO 17225-1 standard, which defines classes, grades, and fuel properties.  The ash content of biomass can vary considerably in different parts of the tree, with lower levels in heartwood than sapwood, and much higher levels in bark. The ash content of typical BC wood ranges from 0.2 to 3.0%. However, bark can contain 3.5% or more ash depending on the wood species, the handling procedures, and the amount of soil contamination resulting from harvesting activities.  A seller trying to meet a tight ash content specification has options.  Eliminate dirt, rocks, and bark through proper handling or screening and the ash content should be lower, with a corresponding higher price.  If the bark can be sold elsewhere, where its higher energy content is beneficial to another buyer, then the supply chain is better diversified and commercial risks associated with one buyer – one seller markets are avoided.

Solving the particle size challenge

Particle size is another challenging quality attribute for bioenergy and bio-liquids processes particularly where the seller is sourcing raw material in the form of a whole tree, log or bolt, or slash pile for conversion to a feedstock.  Generally speaking, most buyers are looking for specific particle sizes that allow them to optimize their conversion process.  If they are able to purchase a tightly specified particle size, eliminating as much of the fines or overs as possible, then they can and will pay a higher price.  CAN/CSA-ISO 17225-4 provides a classification system for defining the main fraction of the biofuel while limiting the fine and coarse fractions to specified parameters.  The pulp mill industry has perfected this process and dominates the market for clean chips, paying high prices for the on grade product with incentive bonuses for exceeding conformance as measured through a chip quality index.  It should not be very difficult to apply the same principles to ‘hog fuel’.  As always, best practices dictate that the seller applies due diligence in the maintenance of comminution equipment, cutter heads, hammers, anvils, and knives in order to best achieve target particle size distributions and for good measure, minimize energy consumption costs.

CAN/CSA-ISO 17225-1 provides a hierarchical classification and grading of woody biomass by origin and sources.  The specifier can now provide greater clarity for the buyer and seller on what part of the tree the biomass originates from and from what part of the supply chain it is sourced from.  Categories for whole trees with or without roots, stem wood only, bark only, logging residues, by-products of wood processing plants, and recycled wood are provided for.  The elimination of unwanted fractions is a distinct benefit for the buyer but provides other market opportunities for the seller.  Competition for the same fraction by competing buyers benefits the seller.

It’s a broad standard

These standards are broad enough to accommodate implementation throughout the supply chain.  CAN/CSA-ISO 17225-2 covers wood pellets and 17225-3 covers briquettes.  A pellet manufacturer has a better shot at meeting the standard, including application of the CANplus mark, if its suppliers in turn conform to CAN/CSA-ISO 17225-4 for graded wood chips.  A biomass power plant has a better chance of optimizing operations if appropriate classes of biofuel are available that enable them to improve plant efficiency to shape the load through fuel blending, allowing them to meet time of day peak demand or to back off during off-peak periods.  Bio-diesel plants have a better chance of optimizing conversion efficiencies if the right specification of feedstock is delivered through the front end of the plant.

There are other benefits that may manifest themselves as the standards become more widely used.  Health and safety aspects of biomass processing and handling can naturally be built into such management systems.  Local authorities may regulate fuel specifications to ensure emissions targets are met. The documentation arising from the implementation of these third party monitored, methodical quality management systems will be useful in proving due diligence in satisfying monitoring requirements.  Best practices for biomass storage, transportation, and handling are a natural add-on to the system.  Selection of biomass processing equipment will be enhanced by ensuring that equipment manufacturers are able to design and meet specifications and be held to account for performance against a known standard. These standards are long overdue.

The industry needs to start thinking about how these standards might best be rolled out and made to work.  So let’s think for a moment of W. Edwards Demming’s iconic statement: “Defects are not free. Somebody makes them, and gets paid for making them”.  And remember that every defect that was once in the tree is now somewhere in your ‘hog fuel’.

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