Any good sawmill aims to use as much of every tree as possible. But nature makes that easier said than done. Logs are round, not always straight, and are covered in bark. This means even the most technologically-advanced sawmills can only use around 60% of a log to create high-quality timber.
But what happens to the rest? The ‘waste’ products from timber production such as bark, shavings, sawdust and wood chips can’t be used to create lumber, but they aren’t worthless. In fact, these residuals have long been used to make paper, cardboard or fiber-board.
With the world growing increasingly digital the markets for residuals for pulp have been in decline. But with the growth of markets for biomass, in the form of sustainable wood pellets – which can utilize the same residuals for production of pellets and other parts of the process – there remains a sustained demand and market for this material.
As this market continues to grow, so will demand. Finding ways in which this market can be made more efficient today could lead to benefits in the long term.
A new collaboration between Drax Biomass and Louisiana-based Hunt Forest Products is helping do precisely this through investment in a co-location site in Urania, LA which will see a sawmill and pellet facility sitting side by side.
This innovative cooperation will help cut down costs, save time, reduce emissions, and deliver more efficiencies to the industrial wood pellet industry.
Creating a virtuous cycle
A healthy market for residuals is important for sawmills and it creates an additional revenue stream for their business.
However, even if buyers are available it can be expensive to transport light, loose materials such as bark, sawdust and so on, and this can mean they are trucked to landfills nearby or simply burned on site. Finding a buyer close to hand, however, can lower transport costs and reduce overall environmental impact.
In Urania, Hunt Forest Products is planning a new mill that will occupy 125 acres and sit right next to Drax Biomass’ existing pellet facility, LaSalle BioEnergy. Hunt’s new mill is located to take advantage of the abundant trees of sawlog size that fill the surrounding forests.
This new mill will aim to produce approximately 200 million board feet of lumber annually, use 850,000 tons of wood, and employ 110 people once fully operational. Naturally, the scale of the operation means it will also produce significant residuals, much of which will go to DBI’s pellet facility next door which is already equipped to process it.
The type of raw fiber that Hunt will deliver to us is perfect for making compressed wood pellets, a form of biomass suited for use in converted, former coal power stations. It’s already chipped and much of it will already be dried, meaning it can skip the early parts of the pelletization process and go straight to the high-pressure hammer mill.
“This lowers our carbon footprint, and is an incredibly efficient, cost-effective way to capitalize on wood residuals – it makes perfect sense for our business model,” says Richard Peberdy, VP, Sustainability at Drax Biomass.
In addition to helping lower the cost of production and, in turn, the cost of pellets and renewable energy, the local market for the residuals from the sawmill will help lower lumber production costs. This will help maintain the healthy market for wood from sustainably managed forests. The market for sawlogs has been shown to be a critical factor in providing revenue to forest owners, allowing them to invest in better forests for the future.
So, while the co-location of sawmill and pellet manufacturing facility may seem a small project, it is one that will have wider benefits – for the industry, the community and for the environment.
Heard of hog fuel? The name might not be immediately familiar, but it’s likely you’ve come across it somewhere, in some form.
A type of fuel made from the unprocessed waste debris, bark and organic matter produced as a result of commercial forestry, hog fuel is used to power things like boilers and dryers at industrial forestry facilities (as it is at Drax Biomass’ pellet manufacturing plants). However, it has wider uses, such as for lining flower beds and garden paths, too.
In short, it’s a valuable and versatile substance. But what else is there to know about hog fuel?
The most eye-catching thing about hog fuel is its name, and this has several possible origins. One is the instrument used to create it: a hammer hog – a machine made up of several spinning hammers that chip wood and wood fiber down into small, rough pieces. The other possible derivation is from Norway, where ‘hogge’ and ‘hogde’ literally mean ‘chopped’ (present and past tense respectively). There’s no consensus on which of these origins hog fuel owes its name to, however – instead, it’s likely indebted to both.
What it’s made of
Like its porcine cousin the sausage, hog fuel can be made from a wide array of ingredients. However, all come from the forestry and wood products industries and are all thought of as waste products. The rule is, if a wood product isn’t good for anything else, it’s good for hog fuel.
Hog fuel includes bark, wood chippings, shavings and sawdust – all plentiful by-products of forestry and saw mills. Because hog fuel is often piled up outside, on the ground, dirt and even ice (in cold enough climates) can end up in the mix. However, an increasing amount of hog fuel customers are moving hog fuel to hoppers and bins, or at least a cement pad, to reduce foreign debris.
How it’s used
The most common use of hog fuel is to power equipment used within the forestry industry. At Drax Biomass’ pellet facilities this means it’s used to fuel the massive dryers, which ensure wood chips have a moisture content of between 11.5% and 12% before being pelletized. Trucks travelling between forest and facility arrive at Drax’s pellet plants throughout the day to deliver it, helping ensure nothing goes to waste from properly managed forests.
However, it also has uses beyond as a fuel. Its toughness and resilience makes it a great material for flooring outdoor areas likely to sustain heavy impact, like paddocks, dog tracks, and pathways.
Hog fuel may not be the most glamorous part of the forestry industry – neither its name nor its physical characteristics make it particularly attractive. What is, however, is how it turns a plentiful waste product into a useful, renewable fuel.
Buddy Lewis began working in Mississippi’s forestry industry in the 60s. Back then, forestry was a very different game.
“When I first got started, workers would go out into the forest, cut the trees down with a chainsaw, put the logs over their shoulders and throw them into a truck,” he says. This was in 1968 – since then, a lot has changed.
“That business just doesn’t exist anymore. Now it’s all mechanized. One man on a machine can cut more trees in a day than 15 guys with chainsaws.”
Technology, it turns out, has transformed the forestry industry, just as it has transformed so many other sectors of the economy. So too have customers, and Lewis’ customers today include wood pellet manufacturer Drax Biomass, whose pellets are shipped around the world for use as a renewable, low-carbon fuel to generate electricity.
Yet despite the impacts from mechanization and a shifting customer base, Mississippi’s forests have long been accustomed to change.
Working the land
When Europeans first settled the heavily-forested US south, much of the land in Mississippi was converted to cotton production and cattle pasture. But after years of intensive agriculture, including past practices that damaged soil quality, timber re-emerged as the dominant crop.
“People found the land would no longer grow cotton or root crops,” Lewis explains. “The cattle market would come and go, but a lot of people just found it better and more profitable to grow trees.”
Today, roughly 65% of Mississippi is covered in forests, thanks in large part to the state’s ideal climate and growing conditions. When Lewis first entered the forestry industry in 1968, he quickly recognized the growth opportunities (both literal and figurative) and decided to become a landowner in addition to a timber trader.
“At any stage I could’ve made a living just buying and selling timber. I could’ve made a living without the land. But the opportunity came up,” he says. “If someone says, I’ll take $500 for this land, and you see land that can support at least $500 worth of timber on it, then it makes sense to take it,” he says.
This long-term mindset is common among landowners like Buddy. Not only does such a mindset encourage planting and harvesting decisions that yield a steady income stream over many years, but it also promotes sustainable land management practices that ensure the land remains forested for future generations.
Saw logs, pulpwood and chip-n-saw
Today, Lewis owns roughly 5,400 acres of land. He typically plants 500 trees per acre, and he harvests those trees in three stages. The most valuable trees are sold as ‘saw logs’. These are typically harvested at full maturity – around 25 years of age – and Lewis estimates that each acre will yield roughly 60–80 saw log-quality trees. The remainder will be harvested early as part of a land management regimen known as ‘thinning’. This practice encourages forest health and productivity, and it also support the landowner’s financial well-being by maximizing the number of saw-log quality trees per acre.
The first thinning is performed when a stand of trees reaches 12-14 years of age. During this process, Lewis and other landowners will typically remove between 50 and 65% of the trees on a given acre. The harvested material is referred to as ‘pulpwood’, and it was traditionally sold to paper mills. But in many parts of the South, the pulp and paper industry has consolidated and mills have closed, leading to a shortfall in demand for pulpwood in some markets. Fortunately for Lewis and other landowners, the wood pellet industry has since emerged as an alternative pulpwood buyer to ensure healthy demand exists for this material.
A second thinning is performed several years later, usually when the trees have reached 18 years of age. This harvested material is referred to as ‘chip-n-saw’, and is often sold to sawmills to produce small-dimensional lumber for construction.
A change of seasons
The closure of paper mills across Mississippi and other parts of the South has been hard on many local wood suppliers. And even though Lewis’ primary paper mill customer has remained in business, the addition of new markets – specifically pellets – has placed his business on sturdier ground.
“[Businesses] like Drax take a commodity we already have, and stabilize market demand for [biomass],” he explains.
Despite the many industry changes during his long career, forestry is a job Lewis wouldn’t swap for the world. “The greatest achievement is that I’ve been allowed to grow old in this business. I’m 71 years old and I work every day in the woods and I love it. I can’t conceive of doing anything else.”
What is soil? It’s something we take for granted, but how often have you stopped to consider exactly what it’s made of, how it works, and why it’s important?
Well, turns out it’s pretty important. The ‘pedosphere’ – as it’s scientifically known – sits alongside the atmosphere, the biosphere, the hydrosphere (the planet’s water systems) and the lithosphere (the earth’s crust and upper mantle) as one of the key elements of our ecosystem.
It plays a crucial role in maintaining the earth’s nutrient cycle, it helps manage the climate, and it’s home to one of the world’s richest biological diversities. Just one gram of soil contains billions of organisms – many of which are still obscure to science.
Sadly, however, it’s under threat. It’s estimated it takes roughly 500 years to form about 2.5 cm of topsoil (the dark, nutritious soil at the top, essential for plant growth). And because it’s not being created as fast as it’s being used – due to things like intensive farming practices – the world is at risk of running out of topsoil entirely.
But there are practices out there that are helping soil, one of which is forestry. Here are three ways forests and forestry are helping soil thrive.
A source of nutrients and habitats
An abundance of biological material is a key ingredient in healthy soil. Without it, soil wouldn’t really be soil, and it certainly wouldn’t be able to grow anything.
Forests continually contribute organic matter to the soil through natural mortality and leaf and branch fall. Responsible thinning and harvest of forests also assures that a component of the tree limbs, leaves, and bark, referred to as harvest ‘slash’, remains on the forest floor. As this woody material decays, it provides a valuable habitat for small animals, who also eventually die, decompose, and become part of the soil.
Healthy soils rely on the circle of life, and forests provide an ample stage for it to happen.
The soil’s structure
Not all soil is created equal. The more porous it is, the more able it is to absorb water and the better it can support other types of life. Rooting plants help this by burrowing through the soil, creating channels called ‘macropores’. The speed at which water is absorbed by soil is known as the infiltration rate, and it has been found that soils with these macropores can absorb water hundreds of times faster than unstructured soil.
Since trees tend to grow much thicker roots than other plants like grasses, they are better at creating macropores. The structure of these channels is further enhanced by the action of decaying organic material, which acts as a kind of glue and helps the soil maintain its shape.
The soil’s shield
Another major threat to healthy soils is soil erosion, which can arise due to any number of factors. High winds can strip soil’s top layer or rain and floods can run into topsoil surfaces and carry it away. And that runoff can have other knock-on effects, filling rivers with silt and disrupting aquatic ecosystems.
Forests can provide protection from these forces. Their cover provides a shield against high winds, while a covering of leaves and other organic matter can protect against impact damage from raindrops and slows water runoff. Slash again has a role to play in this. By providing a physical layer over the ground, this woody debris acts as a shield for the soil below it – not just against the elements but against any tools used in managing the land.
Soil is an integral part of any forest – without it, they simply wouldn’t be able to grow. But like much of the carefully balanced ecosystem, the relationship between soil and tree is a mutually beneficial one. At least one way we can keep soil happy is by keeping forests healthy.
The Amite BioEnergy pellet plant in Mississippi is a site of superlatives. The facility sits on an area bigger than 60 football fields and it can produce up to 450,000 metric tons of compressed wood pellets every year. Amid the bustle of employees and whir of heavy equipment, a single room offers a birds-eye view of it all: the control room.
The men and women inside this room have one of the most important jobs at the plant, and yet a large portion of that job simply involves staying alert and watching.
The wall of monitors
“You can’t let yourself become unfocused. Things can happen in the blink of an eye,” says Cole Wells, a Control Room Operator at Drax Biomass.
From his position inside the control room, Wells can monitor all aspects of the plant’s operations. The centerpiece of the room is a bank of 14 screens, each displaying information on a different step in the manufacturing process.
Wells and his fellow control room operators closely monitor a wide range of parameters, including: the temperature of the massive furnace, which reduces the moisture level in wood chips so they can be converted into pellets; the temperature and operating status of each of the 12 pellet mills; and the inventory within the storage silos that house the finished pellets.
The pellets produced at Amite BioEnergy are used to generate electricity at Drax Power Station in the UK. This process demands precision and accuracy. For example, the wood chips fed into the first stages of the pelletizing process should have a moisture level of between 11.5% and 12% – to ensure the finished product meets exacting design specifications.
Anything less can compromise the durability and performance of the pellet, so it’s essential for the control room to centrally monitor quality across the entire manufacturing process.
One of the control room operator’s most important responsibilities is to quickly identify when a piece of machinery is not operating properly. For this, Wells and his colleagues have the alarm screen.
Acting on alarms
Perhaps the most important visual in the control room is the alarm screen. It tracks plant performance against a set of alarm identifiers, such as high temperatures in critical equipment like the pellet mills.
When an alarm is triggered, the control room operator is immediately alerted. At this point, Wells springs into action.
“First of all I’m going to see what fault we have. Then I notify my operators to see if they can go out to find it,” he explains. The operator out on the plant floor will investigate to determine whether he can fix the fault. If he can’t, then Wells sends in the maintenance team. All of this must happen as quickly as possible – often in less than 10 minutes.
“If we have one fault it could lead to another, so before you know it you could be shutting down production,” says Wells. But tracking and acting on the alarms doesn’t just maintain production – it also keeps employees safe by ensuring that the plant equipment is functioning properly.
The inside of the control room is a very different environment from the rest of the plant. Wells, who began his career at Drax Biomass as an equipment operator, explains: “As a pellet mill operator you’re down [on the floor] turning wrenches. In the control room, it’s not as busy as far as turning wrenches, but you have to do a lot of thinking.”
This story was updated in August 2018 to reflect recent developments within Drax Biomass.
Consider the wood pellet. Drax Power Station in Yorkshire, England uses millions of tons every year to generate electricity. A significant proportion of those pellets are produced right here in the US at three facilities – one in Bastrop, Louisiana; one in Urania, Louisiana, and one in Gloster, Mississippi.
But before they can be used to generate electricity, they must be transported safely and efficiently across the Atlantic. And before that can happen, the pellets must first reach Drax Biomass’ port facility near Baton Rouge, Louisiana.
That initial journey requires both trucks and trains.
The road trip
The Amite BioEnergy pellet plant in Gloster, MS, lies roughly 60 miles from Baton Rouge. Because there is no rail infrastructure within four miles of the plant, it was decided that trucks were the best option for moving the pellets from plant to port.
“Each truck can carry 26.7 tons of pellets per load, and the journey takes around 90 minutes – accounting for the trucks slowing down when they pass through urban areas. It means that one driver can do three trips on any given day,” says Lloyd Wedblad, Director of Logistics at Drax Biomass.
LaSalle Bioenergy in Urania, LA, presented a different challenge as the end strategy is to move all production via rail. Since that plant didn’t have rail available, the temporary solution was to move the volume via road, with the help from local carriers and dedicated providers. Each truck can carry slightly more than Amite, 29.8 tons of pellets per load by using a Harvest permit.
LaSalle is currently building a rail connection and expects to move the first set of railcars to the port by the end of 2018.
Morehouse Bioenergy in Bastrop, LA, presented a slightly more challenging scenario, as the team needed to find a quick and economical way to transport pellets 221 miles to the port.
Riding the railway
A solution was found in the region’s robust rail infrastructure, which includes the short line Arkansas Louisiana Mississippi (ALM) railroad. Opened in 1908, the ALM line runs from the City of Monroe, Louisiana, to Bastrop, just south of the Arkansas state line.
The trains leaving Morehouse BioEnergy use closed-top grain cars rather than open-top coal cars to protect pellets from the elements. Unlike coal, if wood pellets get wet, they quickly deteriorate and cannot be used as fuel at the power plant.
“The cars are designed to carry 143 tons each. But because of local weight limits on bridges and sections of track along the route, we’re limited to 131.5 tons per car. One railcar equates to just under 4 truckloads of pellets,” says Wedblad.
Once the train arrives at the port, it takes around 24 hours to unload before making the return journey to Bastrop.
Morehouse BioEnergy is currently served by 45 car trains, but this will soon change – in a big way. A new railyard planned for the port will allow the team to begin shipping pellets on 80-car ‘unit trains’ – each nearly a mile long and capable of carrying almost double the volume of current trains. Unit trains will deliver major fuel and cost savings to Morehouse, as well as LaSalle BioEnergy and improve Drax Biomass’ overall supply chain efficiency.
Preparing for the overseas journey
The final stage of the pellets’ journey begins along the Mississippi River at the Port of Greater Baton Rouge. As the pellet-laden trucks arrive from Amite, they drive into a customized bay where they unload their cargo onto a conveyor belt in roughly six minutes before returning to the Gloster facility.
But the trains prove to be a more elaborate challenge – one that will get trickier still as the business transitions to 80-car unit trains. When a train arrives at the port, it is divided into several shorter car-lengths (‘cuts’) before each is routed into an unloading facility.
The cars deposit their cargo onto a separate conveyer belt, which – like the belt under the truck bays – moves the pellets into one of the port’s two 44,100ton storage domes.
Once the domes contain enough volume, a cargo vessel arrives for the transatlantic journey to the UK. Yet another conveyor belt moves the pellets from the domes to the dockside shiploader, which loads each cargo hold until the vessel is ready to sail.
A sustainable supply chain
Not only is this journey from plant to port one that is growing more and more efficient, it’s a sustainable one, too. The emissions associated with each stage of the journey is tracked to ensure the Drax Group supply chain is as low-carbon as possible.
Even with all supply chain emissions considered, the power generated all the way in Drax Power Station in the UK has a carbon emissions profile that is 80% lower than coal. Of all the journeys involved in powering the UK’s biggest single site electricity generator, perhaps the most impressive is how this transition from coal to renewable compressed wood pellets has been made.
“We’ve always had a wood industry,” says Kay King, Executive Director of Morehouse Economic Development Corporation, a non-profit organization based in the town of Bastrop focused on developing local businesses. “We’ve had a paper mill [right here in town] since the 1920s. Generations of people worked there. Fathers and sons.”
Bastrop and the surrounding Morehouse Parish sit in northeastern Louisiana near the Arkansas state line. For as long as anyone can remember, the community and its residents have relied on the land for their livelihood. Many of these residents have ties to farming, and many more have ties to forestry and forest products manufacturing.
“We had a paper mill culture here,” King explains. “Everything revolved around the international market for paper.” But that all changed in 2008 during the height of the global financial crisis, when International Paper – then the area’s largest employer – announced the closure of its mill in downtown Bastrop.
“When the last mill closed, the sky fell,” says King. “Economists said the town was going to go away.” The effects were felt not only by the employees, but also by the many local businesses that had supported the mill’s operations. The region’s forestry sector also suffered from this latest mill closure.
“It was devastating to the loggers and the community,” says Buck Vandersteen, Executive Director of the Louisiana Forestry Association. “People were wondering who was going to take care of the forest. The fear was that in the short run, it would be more susceptible to diseases and insects. And in the long run, nobody would invest in paper, so nobody would replant the timber.”
But in 2014, things began to turn around, starting with the construction of two large domes at the Port of Greater Baton Rouge, 200 miles south of Bastrop.
Building a biomass energy plant
“People were asking what NASA was building in Baton Rouge,” Vandersteen recalls with a chuckle.
A year earlier, Drax Biomass had announced plans to build two compressed wood pellet manufacturing facilities in Morehouse Parish and Amite County, Mississippi, as well as a storage and transit facility across the river from Baton Rouge.
They would source low-grade wood from the surrounding forests to produce compressed wood pellets, a form of biomass energy that is used to generate electricity at Drax Power Station in the UK. The two futuristic looking structures that appeared at the port facility are storage domes, used for holding pellets until they are loaded onto cargo vessels for a the long journey across the Atlantic.
In and around Morehouse Parish, Drax’s new wood pellet manufacturing facility is providing new opportunities for the region’s forests and the communities that depend on them.
“Forestry is an economic decision,” says Vandersteen. “If a landowner does not see an opportunity for profit, they’ll turn that land into a parking lot, a mall, or something else.” With the Drax Biomass plant in Morehouse Parish, the region’s landowners now have a greater incentive to retain and reinvest in their forests for the future.
More than money
Today, the pellet manufacturing facility’s impact extends well beyond the forestry sector. Since the facility was commissioned in 2015, the housing market has begun to rebound. Drax is also helping to connect the local economy to the wider region by reopening a stretch of railway that links Morehouse Parish to a mainline track running all the way to Baton Rouge.
Without Drax Biomass, the track would’ve been removed, explains King. “We would’ve never got it back. Drax has given us access to the world. It was there in pieces but they put that together and made it work.”
Most of all, the plant has brought jobs – sixty-five and counting, plus an additional 150 indirect jobs that support Drax’s operations. “It gives people the optimism of saying ‘I have a job.’ It brings rejuvenation,” Vandersteen says. “It brings hope.”
And while the plant’s benefits to the forestry sector and the local economy are clear, it’s the impact on the community’s optimism that will have the longest legacy.
Wood has been used as fuel for tens of thousands of years, but compressed wood pellets are different. Each is the size of a child’s crayon and weighs next to nothing. When produced in bulk, these pellets can be used by power stations to generate reliable, renewable electricity.
Wood pellets also have a positive economic impact on the communities in which they’re manufactured, as the pellet industry supports the many landowners and loggers whose livelihoods depend on a strong market for wood products.
At the Amite BioEnergy facility in Gloster, Mississippi, 450,000 metric tons of pellets are produced each year and shipped to the Drax Power Station in England to generate renewable electricity. This is the story of how those pellets are made.
1. Wood fiber arrives
Trucks arrive at the plant carrying one of the following loads: low-grade roundwood such as thinnings and diseased or misshapen trees; wood chips produced from harvesting residuals, including branches and treetops; sawdust and similar by-products from other wood product manufacturing operations; or bark. The roundwood is delivered to the woodyard where it is staged for processing, while the wood chips and sawdust and delivered directly to the woodchip pile. Meanwhile, the bark is delivered to a separate area where it is stored for use as fuel for the woodchip dryer.
2. Bark is removed
The roundwood in the woodyard is fed into a rotating drum debarker, which tumbles the logs against one another to dislodge the bark. A conveyor belt redirects the bark to a storage area for use as a fuel, while the debarked logs are readied for chipping.
3. The wood is chipped
The debarked logs must be chipped into small, uniformly-sized pieces before they can used to create pellets. A wood chipper at the end of the drum debarker uses multiple spinning blades to cut the logs into chips roughly 10mm long and 3mm thick. The chips are then delivered on a conveyor belt to the woodchip pile, where they await the next step in the manufacturing process.
4. Wood chips are screened for quality
The wood chips sometimes include unwanted material like sand, bark or stones. To remove this waste, the chips pass through a screener to ensure only properly-sized chips reach the dryer.
5. Drying the wood chips
The chips enter an industrial dryer, where they are exposed to a stream of super-heated air produced by burning the bark from the drum debarker. The dryer reduces the moisture level in the wood chips from 50% down to roughly 12% – a critical step in ensuring the quality and energy content of the finished pellets.
6. Dry wood chips are shredded into fiber
The dried chips are then fed into a series of hammer mills that contain spinning shafts mounted with hammers. The hammer mills shred the chips into a fine fiber, the last step before pelletizing.
7. The pellets are formed under extreme pressure
The wood fiber is then fed into the pellet mill where a rotating arm forces the material through a metal die containing a number of uniform small holes. The intense pressure heats up the wood fiber and binds it together as it passes through the die. This process forms the compressed wood pellets.
8. The pellets cool down
The newly formed pellets are then transported to large storage silos, where they can cool and harden while awaiting shipment to the port facility.
9. The journey begins
The pellets are finally loaded on trucks and driven to the Baton Rouge Transit Facility, where they’re stored in specially designed and constructed domes that can safely hold 40,000 metric tons. This is the final stop in the pellets’ journey before being shipped to the UK to be used at Drax Power Station.