Blog by Mark Luntley – Energy4All
“Each silo can hold 2,300 tonnes of woodpellets produced” our guide explained as we walked around a freezing site.
It was towards the end of an hour trip around Ecopower’s woodpellet plant. Our guide was Karel Derveaux – who works with Ecopower – the cooperative that operates the facility.
About a dozen of us were touring one of Ecopower’s key projects – and the Belgian Renewable energy cooperative were justifiably proud. On the outskirts of the industrial area around municipality of Tessenderlo Ecopower entered the “green heat” business, constructing a facility with a production capacity of up to 40.000 tonnes/y of wood pellets for domectic heating, taking in up to 80,000 tonnes of sustainable wood a year. The factory machinery is powered by the electricity from the adjacent power station, with spare heat from aerocondensor used to dry the wood for the pellets production.
The wood used as raw material for the pellets production is most coming from less than 50Km and none further than 150km much coming, when feasible, via the adjacent canal. “There are a lot of woods in Belgium” Karel noted “but we also use sawmill waste and offcuts”. The aim to create a circular process – nothing is wasted. The power station uses low grade woodchips, for instance by chipping forestry remains, roots of trees, woods taken out of composting facilities, ect.. Therefore the energy produced by the power station, both the electricity as the heat, is effectively “green”
The wood comes in “wet” in large logs that are stored on site. “Why not let it dry naturally in the woods?” I asked. “We try to minimise the number of times the log cutters enter the woods to not disturb the habitat” Karel explained.
The logs are picked up in three tonne batches, their barks – which give too much ashes when burned – are stripped. The wood bark is packaged and sold for use in gardens..
The logs then enter the factory where they are chipped and hammer milled prior to being dried. The driers use 100,000 m³ of air an hour – heated by the waste heat from the adjacent combined heat and power station. “We use 5 MW of thermal energy to operate the plant – energy that would have otherwise been wasted” it was explained.
Once dried the wood fibers have to be handled carefully – being so flammable as to be almost explosive. The dried wood fibers was held in a sealed area.
The dried wood fiber is then processed in two ways. Either as briquettes, or as pellets. The pellets are ideal for automatic stoves – where they are fed into a hopper.
“We’ve put a lot of effort into quality control” Karel explained – dusty pellets don’t burn as well and can cause boilers to malfunction. The resulting woodchip is sold in transparent packaging so people can see the quality of the wood pellets.
The pellets and briquettes have very low humidity so are incredibly energy dense. One small pack of briquettes has 50KWh of energy, the equivalent to5 litres of heating oil, and a pallet holds 1,000kg of briquettes.
“We organise regular factory visits where people can come and see what we are doing” Karel explained. “People can see that we source wood ethically, that we operate efficiently and that we really work hard to produce a high-quality and sustainable product.” This helps Ecopower build a successful market share in woodchip in a crowded market.
My last question as we left the plant was “can we buy your cooperative wood pellets in the UK?” Karel smiled before explaining “sadly not” the transport costs would add too much in financial and environmental costs.
His parting words. “You need to do something like this in the UK”