In a throughput hungry industry, biomass producers have long been keen to create as much fuel as possible to maximise their return on investment from capital equipment. But as shredding technologies continue to advance at pace, operators are finding their ROI now comes from different design features — and they’re benefitting the planet in the process. Gary Moore, sales director of UNTHA UK, explores…

Of course it makes sense that the more of a material you can process — and therefore the harder you can make an investment work — the more profitable your operation should become. It’s basic economics. 

Things are no different in the biomass market. Wood processors have long strived to achieve the highest possible throughputs from their shredding technologies, so they can handle a greater volume of input material, create as much on-spec product as they can for resale, and accelerate the payback period from their asset investment. Again, it’s a case of simple maths, and of course the more waste wood that can be transformed in the process, the more renewable fuel we have to utilise as a society, and the tidier sites will become as stockpiles don’t begin to mount.

The challenges of high speed wood shredding

The challenge arises however, in the way such wood shredding machines have traditionally been designed. To achieve high throughputs, many shredders have — perhaps unsurprisingly — been engineered to run at high speeds. Yet while this may satisfy capacity targets — certainly in the early days of a shredder’s life — biomass producers have also found themselves creating a disproportionately high volume of over-sized (non-spec) product which must be re-shredded, and large amounts of non-saleable fines which are subject to costly disposal fees. The machines are also subjected to higher wear rates, meaning disruptive breakdowns become more frequent and operational costs rise due to the excessive purchase of parts and unplanned maintenance. Then there’s the fire risk. The drive train becomes hotter when a shredder runs at higher speeds, therefore the danger of the wood — a highly combustible material — catching alight, rockets. So too do insurance premiums.

This is not to say that these factors prohibit the investment in such machines. Many high speed biomass shredders have been sold globally, with an influx of American machines, for instance, continuing to come onto the UK market, even in recent years. It’s simply a case that biomass producers have accepted all of these operational implications as par for the course in wood waste shredding. But why should this be the norm, when engineering advancements could change the face of what’s possible, when creating biomass or any other alternative fuel?

Slow speed shredding — a feasible alternative?

The emergence of slow speed biomass shredders was met with some scepticism to begin with, because they operate — and sound — extremely different to their higher speed counterparts. But that doesn’t mean they’re not up to the job. Quite the opposite, in fact.

Utilising a higher torque drive, modern biomass shredders can now operate at slower speeds without any detrimental impact on throughputs. The slower speed of the UNTHA XR3000C, for example, combined with special biomass cutter, cutting configuration and gear reducer, means customers can achieve the same impressive throughput figures, yet a higher grade output. Usually in a single step. There are also less fines, less overs, less dust and therefore a significantly reduced fire risk. Lower wear reduces the whole life cost of the machine, the likelihood of unplanned breakdowns plummets, and the net capacity of the biomass line rises, as uptime is higher. 

Greener biomass production

Importantly, and this point will only grow in relevance over the coming years, the XR is also an electrically driven machine. Its Eco Power Drive hit the headlines when the technology was first launched, not least due to its ability to lower fuel consumption and the associated costs by typically 50% — compared to diesel hydraulic machines — therefore further accelerating the ROI on the shredder. Some biomass customers closed the loop completely and powered their XRs using green energy created on their own sites.

The current cost of electricity has lessened the money saving benefits of the Eco Power Drive, but still operators benefit from a cleaner, greener way to produce their biomass. And given we’re producing an alternative fuel to protect the planet in the first place, surely it makes sense that the machines themselves pack a greater sustainability punch.

The search for flexibility 

With quick interchangeable screens, the XR has introduced a new degree of flexibility for biomass manufacturers too, ensuring this machine can handle the full range of waste wood grades to create various on-specification biomass materials.  Such operational versatility — and the opportunity to satisfy the fuel requirements of different offtakers — has never been so important, particularly given the pressures of the economic climate.

Another iteration of the machine has also been engineered — the XR3000RC for green waste. This is likewise a single shaft shredder, with two knife rows. However, unlike the aforementioned technology which requires a ram assist for dealing with bulky wood waste, this isn‘t needed when processing green materials such as trees, shrubs and brush wood. The result is once again a high quality biomass product, or a landscaping mulch material for operators who prefer to pursue that offtaking route.

A market rich with change?

Despite the fiscal climate that we hear about so frequently on the news, the market is ripe with change at the moment. Rising logistics and distribution activity means levels of packaging waste arisings are high — particularly when it comes to wooden crates — and the construction, regeneration and demolition industries remain extremely busy. Such activity is generating more A, B and C wood that can be converted into biomass. 

Demand for biomass shredders is therefore strong, and many machines that have previously been deemed an affordable investment due to their initial purchase price, are now being actively swapped out for technologies that can stand the test of time. The initial capital investment may be higher, but so too is the ROI potential — not to mention the potential environmental gain.