Tag: technology

Why does electricity have a sound?

11 April 2018

Electrification

On cold, misty mornings, the powerlines, pylons and transformers that make up Great Britain’s electricity system sometimes sound a little different. Stand in a field under a powerline and, in the right conditions, the usual sounds of the countryside might be interrupted by the crackling of electricity.

This buzzing crackle, which can be referred to as a corona discharge, occurs when there’s a change from the normal conditions of a power line’s insulators enabling the electric current to partially conduct along it or through the surrounding air to earth. This can come as a result of weather conditions or deterioration of the insulators.

It’s just one of the instances where electricity changes from an unseen force powering our lights and devices to something we can hear, see and even smell.

Why can we hear electricity?

The source of electricity’s sound is also determined by one of its inherent properties: frequency. Frequency is the measurement of multiple occurrences from events, such as sound waves from vibrations, over a period of time. Any equipment that has a frequency causing mechanical parts to undergo repeated change can be audible.

For example, if we hit a cymbal with a drumstick we can hear a crash because of the frequency of the vibrations the mechanical part (in this case the cymbal) makes. We hear a guitar because its strings are plucked and pulled to create vibration at different frequencies. And we can hear an audible hum in a transformer because electric currents affect its internal structure and cause vibrations.

The buzzy tone this creates can be referred to as ‘mains hum’ and is ever present, although not always perceptible to the human ear. It becomes audible, however, when electricity (specifically alternating current – AC) is applied to a transformer.

Transformers are made of lengths of copper or aluminium, which are wound around a steel laminated core. When AC is applied it magnetises the core and causes steel laminations in the transformer to expand and contract in a process known as magnetostriction. Although only small physical changes, these movements are enough to cause vibration, which in turn creates an audible hum.

The crackling overhead

With more than 7,200 km of overhead powerlines humming away constantly around the country, corona discharges are inevitable and common.

This happens when part of the insulators on a high-voltage line begins to deteriorate, is exposed to weather conditions, is damaged or contaminated, allowing electricity to partially flow along it. The surrounding air becomes electrically charged through a process known as ionisation and causes molecules to become charged and collide.

It’s these collisions in the air that make the corona audible. It can also be visible and gives off a distinct smell of ozone, the gas produced when air is ionised.

Although not dangerous to someone on the ground below, if the insulator on the powerline is left to deteriorate further it can fail completely, leading to earth faults that trip power systems.

Making use of electric hums

The sounds electricity creates may seem like a nuisance but they can also have important uses. One of the most innovative applications is in forensic analysis.

A technique called Electric Network Frequency (ENF) enables forensic scientists to validate audio recording by observing the frequency of the mains hum picked up by audio recordings, which is not audible to humans.

By comparing the frequency of the hum in a recording to a database of the country’s frequencies at given times, it’s possible to verify when and in which country the recording took place and detect any editing.

It highlights not only an innovative use of electricity, but just how pervasive and consistent a presence it is. So, while the ebb and flow of electricity through our lives often goes on without thought, it is always there, humming away while it powers modern life in Great Britain.

 

Bitcoin’s electricity consumption problem

2 March 2018

Electrification

Bitcoin is having a breakout year. Its price fluctuations are making headlines all over the world and major investment banks are finally beginning to take it seriously. In short, bitcoin is no longer a fringe currency – it’s becoming a major player.

But for all the advantages it and other decentralised currencies offer, such as low-transaction fees and no intermediaries, there’s a fundamental problem at their core: they use an extraordinary amount of electricity.

According to bitcoin analysis site Digiconomist, the bitcoin network now uses more than 52 terawatt hours (TWh) every year – more than the whole of Portugal, Ireland or Peru. If this rate of growth continues, it’s forecast that by July 2019 it is expected to use more electricity than the US.

So, while bitcoin may be heralded as a saviour from the monopolies of big banks, what does its incredible appetite for electricity spell for the world’s power networks?

Why does bitcoin use so much electricity?

Bitcoin might be an entirely digital currency, but it still needs to be ‘created’, and this requires a process called bitcoin mining.

Bitcoin is a decentralised network, meaning transactions are carried out directly between parties without any central authority. Instead, bitcoin securely records all its transactions through a network made up of thousands of users’ computers.

Bitcoin mining is essentially the process of recording and adding these transactions to the public network or ledger – known as the blockchain. Every 10 minutes, each pending bitcoin transaction is converted into a complex mathematical problem that needs to be solved.

This is where the ‘mining’ computers come in, which use high-powered processing hardware to tackle the mathematical equations and ‘solve’ each transaction. The first miner to successfully crack one of these problems adds that bitcoin transaction to the ledger and is rewarded with an amount of newly ‘mined’ bitcoins – currently set at 12.5 bitcoins (BTC), worth roughly $140,000.

This process isn’t a quick one and relies on large numbers of high-powered computers to solve the problems. One of the largest bitcoin mining rigs in the world – in Ordos, Inner Mongolia –  is made up of eight buildings crammed with 25,000 machines, all cranking through calculations 24 hours a day.

Unsurprisingly, this huge amount of processing power uses a lot of electricity. It also requires a huge amount of space and generates a lot of heat, all of which have sent bitcoin miners around the world in search of cheap electricity, plentiful space and cold weather.

The search for cheap tech power

Iceland and Sweden have become popular destinations for bitcoin mining thanks to its climate (which keeps computer equipment from overheating) and plentiful electricity. In fact, in Iceland, mining is set to reach 840 gigawatt hours (GWh) this year – more than the 700 GWh used by the country’s households.

Iceland’s high level of geothermal and hydroelectric power means these mining operations have a low environmental impact. However, the same can’t be said of the largest bitcoin miner in the world: China.

While it has an abundance of hydropower and an increasing renewable capacity, a large amount of China’s electricity still comes from coal – 72% of its total generation came from the fossil fuel in 2015. This raises concerns around the environmental impact of bitcoin’s increasing electricity needs.

Digiconomist estimates the emissions of just one large-scale, coal-powered bitcoin mining operation (e.g. the operation in Ordos) could fall between 24-40 tonnes of carbon dioxide (CO2) per hour – roughly the same as flying a full Boeing 747-400 for the same period.

However not everyone is convinced the network is as energy intensive as reports suggest, and part of the challenge is that – despite knowing how many bitcoins are in existence – there’s no precise way of knowing how much mining is going on.

What is known, however, is that even as cryptocurrency prices fluctuate, mining is increasing. In short, bitcoin’s incredible appetite for electricity isn’t going anywhere soon. But could it get cleaner?

Moving towards cleaner mining

Some companies are tackling the problem of making bitcoin more sustainable by bringing it off grid and linking it directly to cleaner sources of power, much like how tech companies are striking deals with local renewable suppliers when locating data centres.

Hydrominer, for example, is placing mining hardware directly into hydropower stations, while HARVEST aims to use dedicated wind turbines to power mining, which takes pressure off national grids and their electricity sources.

However, a more fundamental change could be possible: making the protocol used to create bitcoins less energy-intensive.

Ethereum, arguably the main rival cryptocurrency to bitcoin, this year switched from proof-of-work-based mining to proof-of-stake. This means coin creation is not depended on high-powered computers cranking through calculations, but instead through owners validating their stake in the cryptocurrency and ‘voting’ on block creation.

Another alternative is Chia Network, which harnesses unused hard drive storage space for blockchain verification Chia ‘farmers’ for offering storage space for the network.

Both have significant ground to cover to catch the market leader, however, so the more pressing question remains: What’s next for bitcoin? And what will happen as the number of available bitcoins decreases?

The future of bitcoin

Like gold there are a limited number of bitcoins that can ever be mined – 21 million to be precise. This means the reward for bitcoin mining halves roughly every four years as they become more abundant. The next drop is scheduled for 2020 when the reward will slide to 6.25 BTC.

But this doesn’t mean they’re getting easier to mine. In fact, it is growing increasingly difficult, and this means more computer power and a need for even more electricity, which in turn means higher overheads.

A report from JP Morgan estimates the price of mining a single bitcoin has grown tenfold in the last year to $3,920,  a change that could send miners in search of cheaper utilities. More than this, the added stress on grids could lead to a growth in dirtier (and cheaper) fossil fuels which can generate and power mining operations around the clock.

This could mean that as mining becomes more difficult and rewards drop, it will be controlled by fewer, larger-scale operators which can absorb the spiraling costs. Either way, it’s expected they will be forced to reduce their electricity consumption (or at least the cost of it) to remain economical as the rewards they earn cover less of their expenses.

Ultimately, however, if cryptocurrency is set to play a positive role in our future it must become less electricity intensive and work with evolving energy systems to be as sustainable and progressive for the environment as it could be for the global economy.

The history of the pylon

16 February 2018

Electrification

Pylons are one of the most recognisable and perhaps divisive symbols of Great Britain’s electricity system.

There are plenty who decry these metal giants as blotches strung across the country’s green and pleasant landscape. But time has turned the 1930s designs of Great Britain’s pylons into something of a modernist classic, even beloved by some.

What pylons symbolise, however, is more than just the modernisation of the country in the first half of the 20th century. They also represent the promise of safe and reliable electricity for all. There are now more than 90,000 pylons across Great Britain and while the energy system continues to evolve, pylons have changed little since they first went up outside Edinburgh in the 1920s. 

Miesbach to Munich

The first successful attempt to transmit electricity over long distances using overhead wires took place in 1882. German engineer Oskar von Miller and his French colleague Marcel Deprez successfully transmitted 2.5 kilowatts of electricity 57km along a telegraph line.

The simple iron line transmitted a 200 volt current from a steam engine-powered generator near Miesbach to the glass palace of Munich, where it was used to power the motor for an artificial waterfall. The line failed a few days later, and even though it may be a world away from today’s 800,000 volt ultra-high voltage transmission lines, this first trial laid the foundation for the way we move energy today.

Egypt to Edinburgh

Jump to 1928 and there was something new arising on Edinburgh’s horizon. The first “grid tower” was erected here on July 14th as part of the recently established Central Electricity Board’s ambitious project to create a “national gridiron”.

Connecting 122 of Great Britain’s most efficient power stations to consumers was a mission that required 4,000 miles of cables, mostly overhead. Sir Reginald Blomfield was called in to tackle this grand challenge.

Blomfield adopted a design submitted by the American firm Milliken Brothers for the “grid towers” that would criss-cross the country. A staunch anti-modernist – as he made clear in Modernismus, his attack on modern architecture – Blomfield looked to ancient Egypt to name his steel towers.

In Egyptology, a pylon is a gateway with two monumental towers either side of it. These represented two hills between which the sun rose and set, with rituals to the sun god Ra often carried out on the structures. It was an epic name to match the grand ambitions of creating a national grid.

By September 1933 the last of the initial 26,000 pylons that made up the National Grid were installed, less than a third of the 90,000 that make up the system today. The grid was now ready to operate, on time and on budget.

Around the world to underground

As the energy system continues to evolve Great Britain’s pylons are changing too. In 2015, the National Grid unveiled a new Danish-designed pylon that shifts away from the classic industrial tower to a T-framed ski-lift style model designed to minimise the visual impact of the pylons on the landscape.

Another approach also being adopted is burying cables underground. The process of digging tracts and burying cables for thousands of miles could cost as much as £500 million but could help preserve areas of natural beauty while ensuring the whole country has access to the safe and reliable electricity it has come to expect.

As with all change, these announcements have caused a surge in nostalgia for the pylon remembered from childhood car journeys across the country.

Around the globe electricity pylons are now ubiquitous and are being pushed to new technological limits. In 1993 Greenland became home to the longest stretch of overhead powerline between pylons in the Ameralik Span, while China’s Zhoushan Island Overhead Powerline Tie set the record for the world’s tallest pylons in 2010 with two 370-meter towers.

Despite the advancements, it’s notable how little these structures have changed from the those first installed around the world. The proposed humanoid sculptures of Icelandic architecture firm Choi+Shine bare a resemblance to the original skeletal towers of the 30s. And it shows just how successful those original pylons have been at delivering much-needed electricity to homes and businesses around the country.

What will electricity look like in 2035?

14 February 2018

Electrification

The year is 2035. Cars cruise clean streets without the need for a driver, our household appliances are all connected and communicate with one another, and all of it is powered by electricity – specifically low-carbon electricity.

It’s been 10 years since Great Britain’s last coal power station shut down, and across the country wind turbines are generating more electricity than fossil fuels and nuclear energy combined, pushing carbon emissions to a new low.

This isn’t a vision of a green-minded sci-fi novel, this is the forecast for Great Britain in less than 20 years’ time. This sustainable, low-carbon future of 2035 is a significant evolution from today in 2018 and it comes despite a rising population, a continued shift to urban living and an expected rise in power demand. 

Great Britain gets power hungry

If we transport back to the here and now of the late 2010s, it would be easy to expect electricity demand to drop by 2035. In fact, since 2005 electricity demand has been on a steady decline as a result of more efficient appliances and the decline of heavy industry.

By the mid-2020s, however, this trend is expected to reverse. But with the likelihood that appliances will grow more efficient and no sign of heavy industry coming back to British shores, what will drive this growing demand?

Two of the major contributors will be the electrification of transport and the heating system. With the government setting 2040 as the end date for the sale of diesel and petrol vehicles, preparations are already underway for a fully electrified transport network – but it won’t just be restricted to roads.

Train networks and even potentially planes could switch from fossil fuels to electric, increasing demand from the transport sector by 128% between 2015 and 2035. Electric vehicles (EVs) alone are predicted to add 25 terawatt hours (TWh) of electricity demand by 2035, according to a report by Bloomberg New Energy Finance. However, this will be dependent on significant investment in the necessary charging infrastructure to enable a decarbonised transport network across the country.

Added to this will be extra demand from a shift in how we heat our homes. If planning goes ahead and pilot projects are completed, low-carbon, electric heating is expected to begin rolling out in the next decade and will involve the phasing out of gas boilers in favour of electric heat pumps. But as with EV adoption, this will require major government investment and incentives to grow electric heating beyond the 7% of UK homes that use it today.

An electrified heat network will add a greater strain on the electricity system, particularly in winter months when demand is high. The result is a forecast increase of 40 GW in demand during peak times – the mornings and the evenings.

These peak times for electricity consumption will be the greatest test for the grid as intermittent renewables meet more and more of the country’s demand. It raises the question: how we will cope with cold, still and dark November evenings? One solution is the growing role of large scale electricity storage.

By 2035 technological advances are expected to bring electricity storage to 8 GW of installed capacity – double the size of Drax, the UK’s biggest power station. It is also likely that the abilities of EVs as electricity suppliers (delivering excess electricity back to the grid once plugged in overnight) will play an increasing role in meeting demand.

But to ensure this is possible, it will require advances in another sector with a great impact on our power system: technology. This is not just about how technology could enable advances, but how much electricity it’s likely to use.

The internet of everything and a smarter grid

By 2035, chip manufacturer ARM predicts there will be more than one trillion internet of things (IoT) devices globally. This smart technology will be able to turn everything from your morning coffee maker to your bed into intelligent machines, gathering masses of data that can be used to optimise and personalise daily life.

Powering all these devices, let alone the vast plains of servers holding all the data they gather, is one of the great challenges for the IoT industry. However, as much as smart devices will demand energy, they will also help save it.

Thanks to smart, connected devices, traffic lights will turn off when there are no cars, offices will turn off lights when there is no one in a room and homes will understand your energy needs better and tailor appliance usage to your habits. At a larger scale, the introduction of artificial intelligence will allow the entire grid to connect and work in harmony with every one of the billions of devices taking energy from it.

A fully-intelligent system like this will allow grid operators to smooth out peaks in demand by, for example, charging EVs overnight when there is less demand. It means that while there will be an overall greater demand for electricity in 2035, the ‘shape’ of demand may differ from the accentuated peaks of the current system.

Renewable reaction to demand

At its heart, the increasing electrification of our transport, utilities and technology has been driven by a few specific goals, one of which is lowering our reliance on fossil fuels and reducing carbon emissions. It’s positive, then, that all projections towards 2035 have us making significant strides towards this vision.

Coal will have been completely removed from the electricity system, while gas generation will drop to just 70.8 TWh – down from the 112.2 TWh expected in 2018, according to Bloomberg’s forecast. In its place, wind will become the greatest source of our electricity producing 138.5 TWh in 2035, up from 52.3 TWh in 2018. The watershed year for wind power will come in 2027 when wind first overtakes gas to become the biggest contributor to the grid thanks to significant increases in capacity.

Nuclear will still play an important role in the energy mix, contributing 45.8 TWh, while solar will more than double in generation from 12 TWh in 2018 to 25 TWh in 2035 – the same amount of power produced by all of California’s solar panels in 2016.

The results of this continued move to lower carbon sources will be significant. Carbon emissions from electricity in 2035 are expected to be 23.81 gCO2/MJ (grammes of carbon dioxide per megajoule) – less than half what is expected in 2018. And while there will be many major changes in the electricity system over the next 17 years, it is this that is perhaps the most important and optimistic.

5 incredible numbers from the world’s largest biomass port

26 January 2018

Sustainable bioenergy

Since its origins the Port of Immingham has held close links with the UK’s rail and energy networks.

It was the Humber Commercial Railway and Dock company, along with the Great Central Railway, that first established the dock, completing it in 1912 to serve its primary purpose of exporting the most important fuel of the time: coal.

Today, Immingham is the UK’s largest port by tonnage, and while these transport connections endure, they’ve changed with the times. The port is now connected to modern rail infrastructure and helps run a renewable energy system.

Immingham is one of a number of UK ports that receives shipments of wood pellets which are used to generate renewable electricity at Drax Power Station in Yorkshire. With 20,000 tonnes of wood pellets arriving at Drax every day, here are the numbers that tell the story of how the port of Immingham keeps more biomass coming in than any other in the world:

£135 million revamping for renewables

The port began to get serious about renewable energy in 2013 when an investment of around £135m kick-started the creation of the Immingham Renewable Fuels Terminal – the largest biomass handling facility in the world.

Developed by the Associated British Ports as part of a 15-year deal with Drax, the revamp of the former coal port saw an update of its unloading, storage, rail and road facilities to make it biomass-ready.

Getting those 60,000 tonnes of biomass pellets from ship to train to Drax requires tight supply chain systems designed especially for this task.

2,300 tonnes of biomass unloaded every hour

A key component of Immingham is its continuous ship unloaders. Replacing the port’s grab cranes in 2013, these two structures use a combination of suction and an Archimedes screw to discharge 2,300 tonnes of biomass an hour from docking ships.

The continuous unloaders are bespoke for Immingham and designed to keep operating at a constant rate as the Humber’s tide rises and falls. Biomass is drawn up through the unloaders to a conveyer that then takes it all the way from the jetty to one of the port’s eight silos.

120 Olympic-sized swimming pools of storage

Unlike coal, which can be stored in the open air, biomass must be kept dry. Immingham stores wood pellets in eight silos, each capable of holding 25,000 tonnes of biomass.

With the port doubling its storage space from four silos in early 2016, the site’s total capacity now comes in at 336,000m3 – the equivalent of more than 120 Olympic-sized swimming pools.

Here the biomass can be stored for any time between a couple of days and a couple of months, depending on Drax’s demand.

72 trains heading to Britain’s biggest power station every week

The next leg of the journey for the wood pellets sees them moved along the conveyer to board Drax’s specifically designed trains.

Immingham’s rail facilities and Drax’s train wagons were developed to automate the loading process for maximum efficiency. Trains slow down to half a mile per hour as they enter the loading bay where sensors and magnets open the hatch doors of the wagons and close them when they’re full.

The automation of this process allows a 25-wagon train to be filled in just 37 minutes. In total, 12 trains can pass through each day, meaning the port can send 72 trains to Drax every week.

With each hopper’s full load at 71.6 tonnes of compressed wood pellets, each train can carry between 1,700 and 1,800 tonnes. It takes the total biomass reaching the power station from Immingham to a maximum of 130,000 tonnes each week.

£400 million added to the local economy

Drax’s contribution to the Yorkshire and Humber region includes 3,650 jobs and a £419.2 million economic impact.

This is primarily the result of the impact made by Drax Power Station to the region, however, its support of other businesses along its supply chains means its economic contribution is felt far beyond its Selby site.

In 2016, Drax indirectly supported 1,800 jobs in Yorkshire and the Humber region at facilities such as Immingham. Its indirect economic contribution came to £117 million, as the region’s biomass industry became increasingly important.

Find out about another major UK port that has been transformed thanks to renewable energy. How does biomass get shipped to the UK? Read the story of one of the US ports sending wood pellets to UK shores.

How electricity is made

25 January 2018

Power generation

Every morning we take electricity as a given. We switch on lights, charge phones and boil kettles without thinking about where this power comes from.

The electronic devices and appliances that make up our daily routines are not particularly energy intensive. Boiling a kettle only uses 93 watts, toasting for three minutes only requires 60 watts, while cooking in a microwave for five minutes takes 100 watts.

However, when people are waking up and making breakfast in almost 30 million households around the UK, those small amounts soon create a significant demand for electricity. On a typical winter’s morning, this combined demand spikes to more than 45 gigawatts (GW).

So this is what it takes to power your breakfast – from the everyday toaster in your kitchen backwards through thousands of miles of cables to the hundreds of thousands of tonnes of machinery in wind farms, hydro-electric dams and at power stations such as Drax where electricity generation begins.

The grid 

The journey starts in the home where all our electricity usage is tracked by meters. These are becoming increasingly ‘smart’, displaying near real-time information on energy consumption in financial terms and allowing more accurate billing. There are already 7.7 million smart meters installed around the UK, but that number is set to triple this year, paving the way for a smarter grid overall.

What brings electricity into homes is perhaps the most visible part of the energy system on the UK’s landscape. The transmission system is made up of almost 4,500 miles of overhead electricity lines, nearly 90,000 pylons and 342 substations, all bringing electricity from power stations into our homes.

Making sure all this happens safely and as efficiently as possible falls to the UK’s nine regional electricity networks and National Grid. Regional networks ensure all the equipment is in place and properly maintained to bring electricity safely across the country, while National Grid is tasked with making sure demand for electricity is met and that the entire grid remains balanced.

The station cools down

One of the most distinctive symbols of power generation, cooling towers carry out an important task on a massive scale.

Water plays a crucial role in electricity generation, but before it can be safely returned to the environment it must be cooled. Water enters cooling towers at around 40 degrees Celsius, and is cooled by air naturally pulled into the structure by its unique shape.

This means those plumes exiting from the top of the towers are, rather than any form of pollution, only water vapour. And this accounts for just 2% of the water pumped into the towers.

Drax counts 12 cooling towers, each 114 metres tall – enough to hold the Statue of Liberty with room to spare. Once the water is cooled it is safe to re-enter the nearby River Ouse.

The station’s bird’s-eye view

The control room is the nerve centre of Drax Power Station. From here technicians have a view into every stage of the power generation process.  The entire system controls roughly 100,000 signals from across the power station’s six generating units, water cooling, air compressors and more.

While once this area was made up of analogue dials and controls, it has recently been updated and modernised to include digital interfaces, display screens and workstations specially designed by Drax to enable operators to monitor and adjust activity around the plant.

The heart of power generation 

At the epicentre of electricity generation is Drax’s six turbines. These heavy-duty pieces of equipment do the major work involved in generating electricity.

High-pressure steam drive the blades which rotates the turbine at 3,000 revolutions per minute (rpm). This in turn spins the generator where energy is converted into the electricity that will eventually make it into our homes.

These are rugged pieces of kit operating in extreme conditions of 165 bar of pressure and temperatures of 565 degrees Celsius. Each of the six turbine shaft lines weighs 300 tonnes and is capable of exporting over 600 megawatts (MW) into the grid.

One of the most important parts of the entire process, turbines are carefully maintained to ensure maximum efficiency. Even a slight percentage increase in performance can translate into millions of pounds in savings.

Turning fuel to fire

To create the steam needed to spin turbines at 3,000 rpm, Drax needs to heat up vast amounts of water quickly and this takes a lot of heat.

The power station’s furnaces swirl with clouds of the burning fuel to heat the boiler. Biomass is injected into the furnace in the form of a finely ground powder. This gives the solid fuel the properties of a gas, enabling it to ignite quickly. Additional air is pumped into the boiler to drive further combustion and optimise the fuel’s performance.

Pulveriser

How do you turn hundreds of tonnes of biomass pellets into a powder every day? That’s the task the pulveriser take on. In each of the power plant’s 60 mills, 10 steel and nickel balls, each weighing 1.2 tonnes, operate in extreme conditions to crush, crunch and pulverise fuel.

These metal balls rotate 37 times a minute at roughly 3 mph, exerting 80 tonnes of pressure, crushing all fuel in their path. Air is then blasted in at 190 degrees Celsius to dry the crushed fuel and blow it into the boiler at a rate of 40 tonnes per hour.

The journey begins: biomass arrives

Biomass arrives at Drax by the train-load. Roughly 14 arrive every day at the power station, delivering up to 20,000 tonnes ready to be used as fuel.

These trains arrive from ports in Liverpool, Tyne, Immingham and Hull and are specially designed to maximise the efficiency of the entire delivery process, allowing a full train to unload in 40 minutes without stopping.

The biomass is then taken to be stored inside Drax’s four huge storage domes. Each capable of fitting the Albert Hall inside, the domes can hold 300,000 tonnes of compressed wood pellets between them.

Here the biomass waits until it’s needed, at which point it makes its way along a conveyor belt to the pulveriser and the process of generating the electricity that powers your breakfast begins.

The wooden buildings of the future

22 January 2018

Sustainable bioenergy
Wooden building with blue sky background

When we think of modern cities and the buildings within them, we often think of the materials they’re constructed from – we think of the concrete jungle.

Since the 19th century, steel, glass and concrete enabled the building of bigger and more elaborate buildings in rapidly-growing cities, and those materials quickly came to define the structures themselves. But today that could be changing.

New technologies and building techniques mean wood, a material humans have used in construction for millennia, is making a comeback and reducing the carbon footprint of our buildings too.

Return of the treehouse

Civilisation has been building structures from wood for longer than you may realise.

Horyu-ji Temple in Nara, Japan

The 32-metre tall Pagoda of Horyu-Ji temple in Japan, was built using wood felled in 594 and still stands today. The Sakyumuni Pagoda of Fogong Temple in China is nearly twice as tall with a height of 67 metres. It was built in 1056.

Today, wood is once again finding favour.

The 30-metre tall Wood Innovation and Design Centre of the University of British Columbia (UNBC) in Canada was completed in October 2014 and is among the first of this new generation of wooden buildings. And they’re only getting bigger.

This year, the completion of the 84-metre, 24-storey HoHo Tower in Vienna will make it the tallest wooden building in the world. But this will be far surpassed if plans for the Oakwood Tower in London are approved. Designed by a private architecture firm and researchers from the University of Cambridge, the proposed building will be 300-metres tall if construction goes ahead, making it London’s second tallest structure after The Shard. And it would be made of wood.

Falling back in love with wood

Wood construction fell out of favour in the 19th century when materials like steel and concrete, became more readily available. But new developments in timber manufacturing are changing this.

Researchers in Graz, Austria, discovered that by gluing strips of wood with their grains at right angles to each other the relative weakness of each piece of wood is compensated. The result is a wood product known as cross-laminated timber (CLT), which is tougher than steel for its weight but is much lighter and can be machined into extremely precise shapes. Think of it as the plywood of the future, allowing construction workers to build bigger, quicker and lighter.

Glued laminated timber, commonly known as glulam, is another technology technique enabling greater use of wood in more complex construction. Manufactured by bonding high-strength timbers with waterproof adhesives, glulam can also be shaped into curves and arches, pushing wood’s usage beyond straight planks and beam.

These dense timbers don’t ignite easily either. They are designed to act more like logs than kindling, and feature an outer layer that is purposefully designed to char when exposed to flame, which in turn insulates the inner wood.

Susceptibility to mould, insect and water damage is indeed a concern of anyone building with wood, but as the centuries-old Pagodas in Japan and China demonstrate, care for wood properly and there’s no real limit to how long you can make it last.

So, wood is sturdy. But so is steel – why change?

Green giant

Construction with concrete and steel produces an enormous carbon footprint. Concrete production on its own accounts for 5% of all our carbon emissions. But building with wood can change that. UNBC’s Innovation and Design centre saved 400 tonnes of carbon by using wood instead of concrete and steel.

On top of that, building with wood ‘freezes’ the carbon captured by the trees as they grow. When trees die naturally in the forest they decompose and release the carbon they have absorbed during growth back in the atmosphere. But wood felled and used to construct a building has captured that carbon for as long as it stands in place. A city of wooden buildings could be a considerable carbon sink.

This can have further ripple effects. The more timber is required for construction, the more it increases the market for wood and the responsibly-managed forests that material comes from. And the more forests that are planted, and managed with proper governance, the more carbon is absorbed from the atmosphere.

According to research from Yale university, a worldwide switch to timber construction would, on its own, cut the building industry’s carbon emissions by 31%.

Granted, that will be a difficult task. But if even a fraction of that can be achieved, it could mean a future of timber buildings and greener cities.

Can electricity power heavy-duty vehicles?

3 January 2018

Electrification

On a blacked-out stage, a blast of white light appears. Smoke floods out, music blares and an excited crowd surges forward, smartphones held aloft. It’s a moment of rapture – but this is not a theatrical or musical performance. This is the launch of an electric car.

Specifically, the launch of Tesla’s new electric roadster – which claims to be the fastest production car ever made. And while the sportscar may have been the undoubted star of the event, it wasn’t the only one unveiled. Tesla also launched an electric-powered articulated lorry – the Semi.

With governments around the world setting ambitious plans to ban the sale of petrol-and-diesel-only cars, the introduction of electric-powered utility vehicles – like Tesla’s truck – in a range of industries will be essential to a truly decarbonised transport system.

Disrupting trucking

Tesla’s heavy goods vehicle (HGV) highlights the growing capabilities of electric vehicles (EVs) to deliver more than just short, urban journeys. It claims its Semi will be able to travel 500 miles on a single charge (enough to get you from London to Edinburgh comfortably) and tow 40 tonnes of cargo.

Tesla isn’t the only player with electric big rig concepts – Los Angeles-based Thor Trucks, Daimler and Volkswagen have unveiled their own – but its ambitious 2019 production target makes it a more immediate possibility than any other in the space.

Despite media coverage claiming the Semi’s mega-charging capability breaks the laws of physics, big business is taking a sunny view of Elon Musk’s latest innovation. Walmart, which has been taking strides to reduce its emissions, has already pre-ordered 15 of the Semis. Delivery firm UPS has used small electric trucks in major cities for some years already – it has placed the largest order so far, for 125.

Electrifying emergency response

In the world of emergency services, quick response is vital. EVs, then, which have fast acceleration and are quick off the mark, are ideal candidates to deliver – especially as battery technology becomes more reliable and durable.

Health services in Nottingham have already been trialling electric-powered fast response vehicles, while in Japan, Nissan has unveiled an all-electric ambulance that carries a lithium-ion auxiliary battery to power medical equipment on board.

This on-board power supply is a further advantage of EVs, and one not just restricted to emergency services. Electric pickup truck maker Havelaar, for example, offers power outlets on its Bison vehicle for electric tools.

The future of battery farming

Out in the countryside, EVs are making waves in farming. John Deere has unveiled plans for fully electric tractors, claiming they require less maintenance and have a longer lifecycle than combustion engines.

With more than a third of UK farms generating their own power from solar, wind and even anaerobic digestion using farm by-products, there’s potential for farmers to charge tractors renewably and cut their fuel and charging costs.

More than just helping cut emissions and costs, there can also be performance benefits. Given their acceleration abilities, electric tractors are well suited to heavy pulling without revving up engines and churning up ground.

Joining HGVs and tractors in their ability to apply almost instant torque to heavy industrial jobs are e-Dumper trucks. The Komatsu quarry truck weighs in at almost 45 tonnes and claims to be the biggest EV in the world.

The economic advantage of electrification

Air pollution and greenhouse gas emissions are the main driving force behind many anti-fossil fuel regulations. However, research suggests decarbonising transport systems also have economic advantages for businesses.

A report by financial services firm Hitachi Capital found that switching vans and heavy goods vehicles (HGVs) to electric or other alternative fuels could save British businesses as much as £14 billion a year.

It claims EVs run at 13p cheaper per mile than diesel-fuelled vans, while HGVs are reported to be 38p cheaper. That adds up to total savings of £13.7 billion a year if all Britain’s commercial vehicles were switched.

The move to a fully electrified transport system is already underway. The number of registered electric cars increased by 280% in the UK over the past four years, according to the Hitachi report. The Chinese city of Shenzhen’s entire fleet of 16,359 buses has gone electric – a transition that began in 2009 and has been assisted by an 80% drop in the cost of a lithium-ion battery pack. According to Bloomberg New Energy Finance, China’s need for electric bus batteries is almost on a par to that of all global EV battery demand. China could be said to be driving the market.

EVs are undoubtedly cleaner when it comes to road-side pollution. However, the exponential increase in EVs will only benefit the fight against man made climate change if countries’ entire energy systems continue to decarbonise. Emissions-free vehicles will need to be powered predominantly by low carbon electricity for a more electric future to be a sustainable one.

Refurbishing a 300-tonne generator core within the heart of a power station

6 December 2017

Power generation
Electricity generator

At the centre of Drax Power Station, in a corner of the cavernous turbine hall, is a white box. The inside of this box is spotlessly clean. Not only are its white walls free of dirt, they are free of even dust. But there is one outlier inside this sterile environment: a 300-tonne chunk of industrial equipment.

This equipment is a generator core – the central component for converting the mechanical energy to electrical power.

Electricity generator core

The core is driven by the steam turbine. Ninety tonnes of generator rotor spinning at 3,000 rpm with just millimetres of clearance from the core produce 660 megawatts (MW) of electricity. That’s enough – 645 MW when exported from Drax into the National Grid – to power a city the size of Sheffield.

The generator is a serious piece of industrial machinery. And despite the pristine conditions, this white box is the site of serious engineering.

A process normally done by large-scale manufacturers in dedicated factories, ‘rewinding’ a generator core – as the process is called – is a major operation.

No other UK facility is capable of doing this complex job. So it’s here, in a white box, in the middle of an operational power station in North Yorkshire, that a team of engineers is undertaking work that will secure the generator’s use for decades. This is the Drax rewinding facility.

Turbine structure

How a generator works

A generator consists of two main components, a spinning rotor and a stationary stator. The rotor, which is directly connected to the main turbine and spins 50 times every second, sits inside the stator. Both the stator and the rotor contain a large number of copper coils known as windings. These windings are what carry the electrical current.

The rotor acts like a very strong electromagnet, which, when a voltage is applied, produces a strong magnetic field. Because the rotor sits inside the stator, this magnetic field intersects the copper windings of the stator and induces a voltage in these windings, allowing current to flow.  This voltage is then brought out of the stator and passed through a step-up transformer, where it is increased to a level suitable for transmission through the National Grid.

The stator core is made from many elements with hundreds of thousands of laminations, 84 water-cooled insulated copper bars, each 11 metres long and weighing 200kg forming the windings, various insulating materials, blocks, packing, wedges and condition monitoring equipment.

Generator stators can operate for decades without fault.

DIY at Drax

In 2016, a team of engineers at Drax embarked on a project to construct a facility to rewind the stator on site. This required cross-company collaborative working to design and construct this huge purpose built facility.

Contamination can cause operational problems, so the team built a sterile, white room within the turbine hall – one of just two places within the power station with foundations strong enough to support the incredible 450 tonnes required for the rewind facility. Designed to hold the stator core and the conductor bars, air is forced out of the room to limit the possibility of contamination to the core during the rewind.

“When the unit is in service it becomes magnetic, so any metallic particles left in the space will be attracted to the core,” explains Drax electrical engineer Thomas Walker. “Once magnetised, any metal particles could be drawn in, burrowing into the insulation and core lamination.”

This is the kind of event that an electricity generator wants to avoid – but when it happens, be prepared to fix it.

Roll with it

When Drax’s stators were manufactured in the 1980s, completing their construction relied on manual handling techniques. Modern day facilities, however, rotate the core to minimise human contact.

It took just six months for a partnership involving Drax, Siemens and ENSER to manufacture what could be the largest stator rollers in the world and within that time, ship them from the US to North Yorkshire.

With the rollers installed, the next step was to move in the core. Two of the turbine hall’s cranes, each capable of lifting 150 tonnes, were combined to lift it, hoisting the core onto the mechanical ‘roller’ within the rewind facility.

Once in place, the roller rotates the core, allowing for the copper conductor bars to be safely removed and inserted. Despite this mechanical help, the removing and replacing of each one is still at its heart a human job.

“We still need 10 men to physically move the conductor bars with lifting aids, which makes it not an easy process,” says Walker. Using this method, the bars weighing 200kg each can be safely and precisely fitted into the core.

Electricity turbine generator at Drax

Opting for in-house

Rewinding a stator is a complex process. However, when the time, logistics and costs of shipping the core to Siemens – the German-based manufacturers – was factored in, the decision to do the work at Drax Power Station was an easy one.

“A 300-tonne core is not easy to transport and the Highways Agency do not like things like that on the roads. They’d want us to use waterways” says Drax lead engineer Mark Rowbottom. “Logistically it just wasn’t worth it. It’s too much money to move and ship that weight to Germany. So, we looked at what we could do onsite.”

More than just an economical and logistical decision and with the UK’s diminishing manufacturing facilities, Drax is now equipped to support generator rewinds for many years to come. Building and operating the rewind facility was a project that leveraged the engineering abilities of Drax employees. They are increasingly doing engineering traditionally outsourced to equipment manufacturers.

“The experience we have gained and the close working relationship we have established with Siemens enables us to support the generator for the remaining life of the station,” says Rowbottom.

“To see the core in that many pieces and stripped down to this level is very rare,” says Walker, who began working at the plant as an apprentice. Of the 84 conductor bars, half have been fitted, and the team is scheduled to complete the stator rewind in early 2018. “I never thought I’d do anything like this but am proud to say that I’ve done it.”