Tag: technology

This is how you unload a wood chip truck

30 June 2017

Sustainable bioenergy
Truck raising and lowering

A truck arrives at an industrial facility deep in the expanding forestland of the south-eastern USA. It passes through a set of gates, over a massive scale, then onto a metal platform.

The driver steps out and pushes a button on a nearby console. Slowly, the platform beneath the truck tilts and rises. As it does, the truck’s cargo empties into a large container behind it. Two minutes later it’s empty.

This is how you unload a wood fuel truck at Drax Biomass’ compressed wood pellet plants in Louisiana and Mississippi.

What is a tipper?

“Some people call them truck dumpers, but it depends on who you talk to,” says Jim Stemple, Senior Director of Procurement at Drax Biomass. “We just call it the tipper.” Regardless of what it’s called, what the tipper does is easy to explain: it lifts trucks and uses the power of gravity to empty them quickly and efficiently.

The sight of a truck being lifted into the air might be a rare one across the Atlantic, however at industrial facilities in the United States it’s more common. “Tippers are used to unload trucks carrying cargo such as corn, grain, and gravel,” Stemple explains. “Basically anything that can be unloaded just by tipping.”

Both of Drax Biomass’ two operational pellet facilities (a third is currently idle while being upgraded) use tippers to unload the daily deliveries of bark – known in the forestry industry as hog fuel, which is used to heat the plants’ wood chip dryers – sawdust and raw wood chips, which are used to make the compressed wood pellets.

close-up of truck raising and lowering

How does it work?

The tipper uses hydraulic pistons to lift the truck platform at one end while the truck itself rests against a reinforced barrier at the other. To ensure safety, each vehicle must be reinforced at the very end (where the load is emptying from) so they can hold the weight of the truck above it as it tips.

Each tipper can lift up to 60 tonnes and can accommodate vehicles over 50 feet long. Once tipped far enough (each platform tips to a roughly 60-degree angle), the renewable fuel begins to unload and a diverter guides it to one of two places depending on what it will be used for.

“One way takes it to the chip and sawdust piles – which then goes through the pelleting process of the hammer mills, the dryer and the pellet mill,” says Stemple. “The other way takes it to the fuel pile, which goes to the furnace.”

The furnace heats the dryer which ensures wood chips have a moisture level between 11.5% and 12% before they go through the pelleting process.

“If everything goes right you can tip four to five trucks an hour,” says Stemple. From full and tipping to empty and exiting takes only a few minutes before the trucks are on the road to pick up another load.

Efficiency benefits

Using the power of gravity to unload a truck might seem a rudimentary approach, but it’s also an efficient one. Firstly, there’s the speed it allows. Multiple trucks can arrive and unload every hour. And because cargo is delivered straight into the system, there’s no time lost between unloading the wood from truck to container to system.

Secondly, for the truck owners, the benefits are they don’t need to carry out costly hydraulic maintenance on their trucks. Instead, it’s just the tipper – one piece of equipment – which is maintained to keep operations on track.

However, there is one thing drivers need to be wary of: what they leave in their driver cabins. Open coffee cups, food containers – anything not firmly secured – all quickly become potential hazards once the tipper comes into play.

“I guess leaving something like that in the cab only happens once,” Stemple says. “The first time a trucker has to clean out a mess from his cab is probably the last time.”

How space tech helps forests

20 April 2017

Sustainable bioenergy
Satellite view of the Earth's forests

Can you count the number of trees in the world? Accurately, no – there are just too many, spread out over too vast an area. But if we could, what would we gain? For one, we would get a clearer picture of what’s happening in our planet’s forests.

They’re a hugely important part of our lives – not only for the resource they provide, but for their role in absorbing carbon dioxide (CO2). So properly understanding their scale and what is happening to them – whether increasing or decreasing – and designing strategies to manage this change is hugely important.

The trouble is, they exist on such a vast scale that we traditionally haven’t been able to accurately monitor them en masse. Thanks to space technologies, that’s changing.

A working forest

The view from up there

As far back as World War II, aerial imaging was being used to monitor the environment. In addition to using regular film cameras mounted to aeroplanes to follow troops on the ground, infrared film was used to identify green vegetation and distinguish it from camouflage nets.

As satellite and remote sensing technology developed through the 20th century, so too did our understanding of our planet. Satellites were used to map the weather, monitor the sea, and to create topological maps of the earth, but they weren’t used to track the Earth’s forests in any real detail.

But in 2021 the European Space Agency (ESA) will launch Biomass, a satellite that will map the world’s forests in unprecedented detail using the first ever P-band radar to be placed in Earth orbit. This synthetic aperture radar penetrates the forest canopy to capture data on the density of tree trunks and branches. It won’t just be able to track how much land a forest covers, but how much wood exists in it. In short, the Biomass will be able to ‘weigh’ the world’s forests.

Over the course of its five-year mission, it will produce 3D maps every six months, giving scientists data on forest density across eight growth cycles.

The satellite is part of ESA’s Earth Explorers programme, which operates a number of satellites using innovative sensor technology to answer environmental questions. And it’s not the only entity carrying out research of this sort.

California-based firm Planet has 149 micro-satellites measuring just 10cm x 30cm in orbit around the Earth, each of which beams back around three terabytes of data every day. To put it another way, each satellite photographs about 2.5 million square kilometres of the Earth’s surface on a daily basis.

The aim of capturing this information is to provide organisations with data to help them answer the question: what is changing on Earth? When it comes to forests, this includes identifying things like illegal logging and forest fires, but the overall aim is to create a searchable, expansive view of the world that enables people to generate useful insights.

Rocket flying over the earth

Keeping the world green

All this data is not only vital for developing our understanding of how the world is changing, it is vital for the development of responsible, sustainable forestry practices.

From 2005 to 2015, the UN rolled out the REDD programme (Reducing Emissions from Deforestation and forest Degradation), which, among other functions, allows countries to earn the right to offset CO2 emissions – for example through forestry management practices. Sophisticated satellite measurement techniques not only let governments know the rate of deforestation or afforestation in their respective countries, it can also help them monitor, highlight and encourage responsible forestry.

Satellite technology is increasingly growing the level of visibility we have of our planet. But more than just a clearer view on what is happening, it allows us the opportunity to see why and how it is happening. And it’s with this information that real differences in our future can be made.

4 amazing uses of bioenergy

5 April 2017

Sustainable bioenergy
Large modern aircraft view of the huge engine and chassis, the light of the sun

Bioenergy is the world’s largest renewable energy source, providing 10% of the world’s primary supply. But more than just being a plentiful energy source, it can and should be a sustainable one. And because of this, it’s also a focus for innovation.

Biomass currently powers 4.8% of Great Britain’s electricity through its use at Drax Power Station and smaller power plants, but this isn’t the only way bioenergy is being used. Around the world people are looking into how it can be used in new and exciting ways.

algal blooms, green surf beach on the lakePowering self-sufficient robots 

What type of bioenergy?

Algae and microscopic animals

How’s it being used?

To power two aquatic robots with mouths, stomachs and an animal-type metabolism. Designed at the University of Bristol, the 30cm Row-Bot is modelled on the water boatman insect. The other, which is smaller, closer resembles a tadpole, and moves with the help of its tail.

Both are powered by microbial fuel cells – fuel cells that use the activity of bacteria to generate electricity – developed at the University of the West of England in Bristol. As they swim, the robots swallow water containing algae and microscopic animals, which is then used by their fuel cell ‘stomachs’ to generate electricity and recharge the robots’ batteries. Once recharged, they row or swim to a new location to look for another mouthful.

Is there a future?

It’s hoped that within five years the Row-Bot will be used to help clean up oil spills and pollutants such as harmful algal bloom. There are plans to reduce the tadpole bot to 0.1mm so that huge shoals of them can be dispatched to work together to tackle outbreaks of pollutants.

multi-coloured water ketttlesPurifying water

What’s used?

Human waste

How’s it being used?

The Omni Processor, a low cost waste treatment plant funded by the Bill and Melinda Gates Foundation, does something incredible: it turns sewage into fresh water and electricity.

It does this by heating human waste to produce water vapour, which is then condensed to form water. This water is passed through a purification system, making it safe for human consumption. Best of all, it does this while powering itself.

The solid sludge left over by the evaporated sewage is siphoned off and burnt in a steam engine to produce enough electricity to process the next batch of waste.

Is there a future?

The first Omni Processor was manufactured by Janicki Bioenergy in 2013 and has been operating in Dakar, Senegal, since May 2015. A second processor, which doubles the capacity of the first, is currently operating in Sedro-Woolley, Washington, US and is expected to be shipped to West Africa during 2017.

Closer to home and Drax Power Station, a similar project is already underway. Northumbrian Water was the first in the UK to use its sludge to produce renewable power, but unlike the Omni Processor, it uses anaerobic digestion to capture the methane and carbon dioxide released by bacteria in sludge to drive its gas turbines and generate power. Any excess gas generated is delivered back to the grid, resulting in a total saving in the utility company’s carbon footprint of around 20% and also multi-millions of pounds of savings in operating costs.

Jet plane leaves contrail in a sunset beautiful sky, copy space for textFlying across the Atlantic

What’s used?

Tobacco

How’s it being used?

Most tobacco is grown with a few factors in mind – taste and nicotine content being the most important. But two of the 80 acres of tobacco grown at Briar View Farms in Callands, Virginia, US, are used to grow tobacco of a very different sort. This tobacco can power aeroplanes.

US biofuel company Tyton BioEnergy Systems is experimenting with varieties of tobacco dropped decades ago by traditional growers because of poor flavour or low nicotine content. The low-nicotine varieties need little maintenance, are inexpensive to grow and flourish where other crops would fail.

The company is turning this tobacco into sustainable biofuel and last year filed a patent for converting oil extracted from plant biomass into jet fuel.

Is there a future?

In the hope of creating a promising source of renewable fuel, scientists are pioneering selective breeding techniques and genetic engineering to increase tobacco’s sugar and seed oil content.

In 2013, the US Department of Energy gave a $4.8m grant to the Lawrence Berkeley National Laboratory, in partnership with UC Berkeley and the University of Kentucky, to research the potential of tobacco as a biofuel.

Fukushima Japan

Powering repopulation of a disaster zone

What’s used?

Wood exposed to radiation by the Fukushima nuclear meltdowns

How’s it being used?

Last year it was announced that German energy company Entrade Energiesysteme AG, will set up biomass power generators in the Fukushima prefecture that will generate electricity using the lightly irradiated wood of the area.

It’s hoped they will help Japan’s attempts to repopulate the region following the 2011 earthquake, tsunami and nuclear accident. Entrade says its plants can reduce the mass of lightly irradiated wood waste by 99.5%, which could help Japanese authorities reduce the amount of contaminated material while at the same time generating sustainable energy.

Is there a future?

The prefecture aims to generate all its power from renewable energy by 2040 through a mix of bioenergy and solar power.

This is how you make a biomass wood pellet

6 October 2016

Sustainable bioenergy
Compressed wood pellets

Wood has been used as fuel for tens of thousands of years, but this wood – a compressed wood pellet – is different. It’s the size of a child’s crayon and weighs next to nothing, but when combined with many more it is a smart solution to generating cleaner electricity compared to coal.

Wood pellets like these are being used at Drax Power Station to generate electricity and power cities. Not only are they renewable and sustainable, but because they are compressed, dried and made from incredibly fine wood fibres, they’re also a very efficient fuel for power stations.

This is how a compressed wood pellet is made at the Drax Biomass Amite BioEnergy Pellet Plant in Mississippi.

The wood arrives to the yard

Wood arrives at the plant via truck and is sent to one of four places: the wood storage yard, the wood circle (where wood is primed for processing), the piles of sawdust and woodchip, or straight into processing.

Bark is removed and kept for fuel

Logs are fed into a debarker machine, which beats the logs together inside a large drum to remove the bark. The bark is put aside and used to fuel the woodchip dryer, used later in the process.

Thinned wood stems become small chips

The logs – low-value fibre from sustainably managed working forests – need to be cut down into even smaller pieces so they can then be shredded into the fine material needed for creating pellets. Inside the wood chipper multiple blades spin and cut the logs into chips roughly 10mm long and 3mm thick. The resulting chips are fed into the woodchip pile, ready for screening.

Chips are screened for quality and waste is removed

Chipped down wood can include waste elements like sand, remaining bark or stones that can affect pellet production. The chips are passed through a screener that removes the waste, leaving only ideal sized wood chips.

The biggest hairdryer you’ve ever seen

The wood chips need to have a moisture level of between 11.5% and 12% before they go into the pelleting process. Anything other than this and the quality of the resulting pellets could be compromised. The chips enter a large drum, which is blasted with hot air generated in a heater powered by bark collected from the debarker. The chips are moved through the drum by a large fan, ready for the hammer mill.

Wood pellet Hammer Mill

Small woodchips become even smaller woodchips

Inside the hammer mill there’s a spinning shaft mounted with a series of hammers. The wood chips are fed into the top of the drum and the spinning hammers chip and shred them down into a fine powdery substance that is used to create the pellets.

Putting the chips under pressure – a lot of pressure

The shredded woodchip powder is fed into the pellet mill. Inside, a rotating arm presses the powdered wood fibre through a grate featuring a number of small holes. The intense pressure heats up the wood fibre and helps it bind together as it passes through the holes in a metal ring dye, forming the compressed wood pellets.

Resting and cooling down

Fresh pellets from the mill are damp and hot, and need to rest and cool before transporting off site. They’re moved to large storage silos kept at low temperatures so the pellets can cool and harden, ready for shipping.

One of the biggest domes you’ve ever seen

This is the final stage before shipping. Specially designed and constructed storage domes are used to store the wood pellets after they are transported to the Mississippi River, Louisiana and before they make their way across the Atlantic to the UK.