Tag: power station

The night shift

Draw power station at night

Things are different at night. As darkness falls the familiar sights and sounds that make up daily life retreat, creating a strange yet familiar world. There’s less activity, but that doesn’t mean there is no activity.

While Great Britain sleeps, phones charge and fridges hum. Electricity is a 24-hour need, and so the stations generating it must be 24-hour operations. But the life of a power station by night is very different to that by day.

“Walking around the power station at night can almost feel like the Mary Celeste,” says Simon Acaster, Drax Power Station’s Generation Manager. “There may be as few as 50 to 60 people on site, which isn’t a lot when you consider the size of the plant and compare it to the day, when there are some 650 people around.”

Drax Power Station by day is a hive of activity. Alongside generation there are maintenance, engineering, trading and contract support. At night, this is all stripped back.

“Work is focused on the core production issues: looking after the asset and maintaining power generation output to meet our contract position, keeping the teams safe and making sure we stay environmentally compliant,” says Mark Rhodes, Shift Manager at Drax.

“It’s a quieter place,” he adds.

Keeping power flowing

The nightshift at Drax Power Station

Typically, teams at Drax swap over at 8pm and 8am on a cycle of day and night shifts. During the summer months, when one or more of the station’s six, 600+ megawatt (MW) units can be on outage and maintenance is carried out across the station, work often continues around the clock right through the night.

But during a period of normal operation, the night workforce is reduced to basic operations and maintenance teams, material handling teams receiving biomass deliveries – which continue through the night – and security staff.

Demand for electricity typically falls overnight, so Drax shuts down unneeded generation units around 10pm. As morning approaches teams prep them to restart in time for when people wake up and turn on kettles.

“Even when we shut the units down, the turbine is still turning throughout the night,” says Acaster. “All the hydraulic pumps and lube oil systems are still functioning. A lot of plant is in service even when the units are shut down.”

This means there’s still the potential, as during the day, for something to need maintenance or attention at any moment requiring the teams to jump into action.

“We aim to sort any short-term issues through the night,” says Rhodes. “But for any technical issues that can wait, we tackle them when the day team returns and we’re fully staffed. At night it’s more about safely managing the asset.”

The hardest part of a running the power station overnight, however, is not a technical one, it’s a human one.

“There’s no doubt about it, working nights is tiring,” says Acaster. “The biggest challenge is keeping everybody focused and aware of what’s happening.”

He continues: “Unit controllers regularly talk to their plant operators, checking in every hour so we know they’re safe. Supervisors need to be out on plant engaging and talking to employees, checking on what they’re doing and keeping them active and alert.”

The shifting of the night shift

The decarbonisation of Great Britain’s electricity system has changed the way Drax operates during the day, and the same is true of the night.

“Historically, we had six units and they would be baseload, generating 645 MW each,” says Rhodes. “They would operate continuously day and night.” But with the demand profile changing, lower power prices, and other methods of generation coming onto the system, that model is changing.

“Overnight is normally the time of least demand and when the price of power becomes most depressed,” Rhodes continues. “So we take units off and prepare them for the morning, returning when there is value.”

Regularly shutting down and starting the units takes a tougher toll on the equipment than running them continuously, which increases the need for maintenance teams on night shifts. There’s also a need for teams to be on standby to ramp up or down generation.

The increased volatility of the country’s power network, brought on in part by increasing levels of intermittent renewables, means National Grid can often ask Drax to increase or decrease generation at short notice to provide balancing services like inertia, frequency response or reserve power.

“Our units can come down to 300 MW and stay at that level,” says Acaster. “Across three units that gives National Grid 900 MW of spare capacity that can be turned up. It’s like a sleeping giant awaiting start up at any time.”

But unlike other sleeping giants this one is never truly at rest. The demands of the network keep it, and the men and women operating it, humming through the night, 24-hours a day. The power station at night is a quieter place, but it is never a silent one.

I am an engineer

Producing 16% of Great Britain’s renewable power requires innovative people with the right mix of skills, experience and determination. Running the country’s biggest power station is a team effort – but it’s worth taking a moment to hear from the individuals at the top of their game. Meet Luke Varley, Adam Nicholson, Gareth Newton, Andrew Storr and Gary Preece.

Getting more from less

There are few things in a power station as integral to generating electricity as the turbines. Making sure they run efficiently at Drax is down to Luke Varley and his team.

Luke Varley

Varley is the lead engineer in the turbine section at Drax Power Station. His team who look after what’s arguably the heart of the plant: the steam turbines that drive electricity generation. As well as managing day-to-day maintenance, the engineers and craftspeople within TSG deliver the major overhaul activities on the turbines to keep them running efficiently and safely.

Read Luke’s story

The problem solver

How do you convert a power station built for one fuel to run on another? It takes engineers with out-of-the-box thinking like Adam Nicholson.

Adam Nicholson

Nicholson is Process Performance Section Head at Drax Power Station. He has an eagerness to find solutions. That makes him the ideal candidate for his current job: managing day-to-day improvements at Drax.

His team makes sure the turbines, boiler, emissions, combustion, and mills are not just working, but running as smoothly as possible. It’s a job that brings up constant challenges.

Read Adam’s story

Taming the electric beast

To keep a site as big and complex as Drax Power Station running, you need to be ready to mend a few faults. That’s where Gareth Newton comes in.

Gareth Newton

As a mechanical engineer in one of the power station’s maintenance teams, he’s a man with a closer eye on that animal than most.

And when something does need fixing or improving, it’s his job to make sure it happens. It’s a task that keeps him busy.

Read Gareth’s story

The toolmaster

What do you do when a piece of equipment in the UK’s largest power station breaks down? More often than not, the answer is send it to Andrew Storr’s workshop.

Andrew Storr

Before Drax Power Station was a part of Andrew Storr’s career, it was a part of his local environment.

Today, Storr does more than strip the turbines, he’s part of the engineering team that oversees them – a job that needs to be taken seriously.

Read Andrew’s story

The life of an electrical engineer

Unsurprisingly, running the country’s biggest single site electricity generator requires top-class electrical engineers. That’s where Gary Preece comes in.

Gary Preece

A station like Drax doesn’t run itself. Its six turbines generate nearly 4,000 megawatts (MW) of power when operating at full load. Unsurprisingly, for a site that produces 7% of Britain’s electricity needs, the role of an electrical engineer is an important one – both when managing how power is connected to the high-voltage electricity transmission grid, and how the giant electrical machines generating the energy work.

Read Gary’s story

A positive negative

Tubes running in the direction of the setting sun. Pipeline transportation is most common way of transporting goods such as Oil, natural gas or water on long distances.

This story was updated in June 2018 following the announcement of Drax’s pilot BECCS project.

Is there a way to generate electricity not only with no emissions, but with negative emissions?

It’s an idea that, after decades of being reliant on coal had seemed almost impossible. But as Drax has shown by announcing a pilot of the first bioenergy carbon capture storage (BECCS) project of its kind in Europe, it might not be impossible for much longer.

A few years on from the historic Paris Agreement – which sets a target of keeping global temperature rise below two degrees Celsius – innovative solutions for reducing emissions are critical. Among these, few are more promising than BECCS.

It sounds like a straightforward solution – capture carbon emissions and lock them up hundreds of metres underground or turn the carbon into useful products – but the result could be game-changing: generating electricity with negative emissions.

Capturing carbon

Carbon capture and storage (CCS) technology works by trapping the carbon dioxide (CO2) emitted after a fuel source has been used and moving it to safe storage – often in depleted oil and gas reservoirs underground.

There are a number of CCS technologies available but one of the simplest is oxyfuel combustion. Fuel such as coal, gas or biomass, is burnt in a high oxygen environment and CO2 – rather than carbon (C) or carbon monoxide (CO) – is produced. Other impurities are removed and the resulting pure CO2 is compressed to form a liquid. This CO2 can then be transported via pipeline to its designated storage space, normally hundreds of metres underground.

The UK is well-placed to benefit from the technology thanks to the North Sea – which has enough space to store the EU’s carbon emissions for the next 100 years.

It’s a technology that can drastically reduce the emissions from fossil fuel use, but how can it be used to produce negative emissions?

Two technologies, working as one

Biomass, such as sustainably sourced compressed wood pellets, is a renewable fuel – the CO2 captured as part of its life in the forest is equal to the emissions it releases when used to generate electricity. When coupled with CCS, the overall process of biomass electricity generation removes more CO2 from the atmosphere than it releases.

A report published by the Energy Technology Institute (ETI) looking at the UK has suggested that by the 2050s BECCS could deliver roughly 55 million tonnes of net negative emissions a year – approximately half the nation’s emissions target.

It’s not the only body heralding it as a necessary step for the future. The Intergovernmental Panel on Climate Change (IPCC), stated in a 2014 report that keeping global warming below two degrees Celsius would be difficult if BECCS had limited deployment.

Support is widespread, but for it to lead to a practical future, BECCS needs suitable support and investment.

Morehouse BioEnergy pellet plant

Mills such as Morehouse BioEnergy manufacture compressed wood pellets – a sustainably-sourced fuel for BECCS power plants of the future.

Positive support for negative emissions

There are only a handful of CCS projects in operation or under construction across the world and many simply re-use rather than capture the CO2. Part of the reason is cost. It’s estimated that optimal CCS technology can cost about as much as the power station itself to install, and running it can consume up to 20% of a station’s power output. This means more fuel is needed to produce the same amount of power compared to a conventional power plant of similar efficiency.

Without government support, it remains a prohibitively expensive solution for many power generators. With government support in the form of multi-decade contracts, large CCS or BECCS plants could leverage economies of scale. They could deliver energy companies and their shareholders a return on the investments in the long-term.

Drax research and development

Past plans by Drax could have put the company on a timeline towards becoming the world’s first large scale negative emitter of CO2. It would have achieved it firstly with the construction of a CCS power station at its Selby, North Yorkshire site.

The 428 MW White Rose power station was to be fuelled by a mixture of coal and biomass and once in operation, could have paved the way for similar facilities elsewhere as carbon capture technology improved and costs came down, but unfortunately the project never went ahead.

There are some positive signs that carbon capture technologies are developing around the world. The first ‘clean coal’ power station became operational in the US earlier this month – and a second CCS plant is on the way. A UK-backed carbon capture and use (CCU) project in India recently opened at a chemicals factory, involving the capture of emissions for use in the manufacturing process.

Back in the UK, where the government outlined plans to end coal-fired power generation by 2025, carbon capture power stations must become financially competitive if they are to become a major part of the country’s low carbon future. But if the world is to achieve the targets agreed in Paris and pursue a cleaner future, negative emissions are a must, and BECCS remains a leading technology to help achieve it.

These three inches of copper can power a city

A series of unassuming cables extend out of the turbine hall at Drax Power Station. They’re easily missed, but these few inches of copper play an instrumental role in powering your home. Surging through each one is enough electricity to power a city.

But the process of getting electricity from power station to plug isn’t as simple as connecting one wire to a live turbine and another to your iPhone charger. We need an entire network of power stations, cables and transformers.

Linking the network

When the country first became electrified it did so in stages. Each region of the UK was powered by its own self-contained power supply. That changed in 1926 when the UK set up the Central Electricity Board and began what was at the time the biggest construction project Britain had ever seen: the national grid

The project took 100,000 men and five years to complete and when it was finished it connected 122 of the country’s most efficient power stations via 4,000 miles of overhead cabling. It had a sizeable effect. In 1920 there were roughly 750,000 electricity consumers; by 1938 that had risen to 9 million.

The grid has changed in the 80 years that’s passed, but it remains the network that transfers power across the country to where it’s needed, whenever it’s needed.

“The strange thing about electricity is that you could live 10 miles from a power station and you can’t be sure the electricity you’re using is coming from that station,” says Callan Masters, an engineer with National Grid whose job it is to maintain and upgrade the network. “The whole system works together – the whole system has a demand and the whole system has to deliver it.”

And to do this, the network has to be able to deliver electricity quickly and efficiently. Masters explains: “It acts like a motorway for power.”

High Voltage Tower on Sunset, Electric Pylon on field

Riding the motorway for power

The process of transporting electricity involves a series of stages, the first of which is ‘stepping up’ the voltage.

When electricity is transported via cables or wires it loses some of its energy as heat. Think of a lightbulb – as it illuminates it heats up because it’s losing energy. The lower the current of that electricity, however, the less energy is lost. So to reduce these losses when transporting power, National Grid transmits electricity at low currents, which it can do by increasing its voltage.

At the power station electricity is generated at 23,500 volts and is then ‘stepped up’ to 400,000 volts by a transformer. The first of these is located on a substation on site at the power station.

Once stepped up, the electricity is transported through high transmission cables – before being ‘stepped down’ via a transformer on the other end. This stepped down electricity is passed onto a regional distribution system, such as the overhead cables you might find on top of wooden poles before being stepped down a final time. “That’s the role of a little transformer at the end of your street,” Masters explains. Finally, the electricity is transported via a final cable into your home – this time at 230 volts.

All this needs to happen incredibly quickly. As thousands of kettles are switched on to herald the end of EastEnders, the demand of electricity surges. Delivering that electricity at the touch of a button relies on a complex network, but it starts with those inconspicuous few inches of copper at the power station.

Vikings, airships and ash: the history of Barlow Mound

Airship at Barlow Mound

Barlow Mound is a haven for wildlife. More than 100 different species call it home, including kingfishers, roe deer and falcons. It’s an area that looks like it’s never been touched by the industrialisation that surrounds it. The truth is very different.

Barlow mound is manmade. It was built in the 1970s using residue material from its neighbour Drax Power Station. It’s a success story of using what was then considered a waste material to create something natural and beautiful. But it has a long history before becoming what it is today and to explore that history is to track the outlook of the UK over the last millennium.

The military moves in

The area around Barlow and Drax was an important location for the very first Viking explorers who arrived here from the North Sea via the region’s Ouse and Aire rivers. But it wasn’t until 1086 that it received its first recorded mention, when it was listed as ‘Berlai-leag’ in the Domesday Book.

Translating to ‘a clearing where barley grew’, it was named by Anglo Saxon settlers, who established the region as a mix of farmland, fields and woodlands and it remained agricultural until the early twentieth century, when the country was plunged into war.

When the First World War began in 1914 and the need for new war machines arose, Sir W G Armstrong Whitworth & Co Ltd, a manufacturing company which had obtained the land in 1913 from the estate of Lord Londesborough, set up an airship factory on the site.

During its lifetime the factory constructed three airships, the 25r, R29 and R33, but when WWI ended and demand for airships sank, the factory shut down and the land passed to the Ministry of Defence (MOD).

During the Second World War the area became an important location in the country’s war efforts once again. The MOD set up an army ordnance and command supply depot manufacturing and storing items like mess tins and kerosene lamps. At one point the site also included a Prisoner of War camp.

By the 60s the UK’s needs for defence manufacturing had subsided. Instead, what it needed was more power. With the rich coal seams of the area and the existing rail network (the Hull-Barnsley line ran through), building a power station in the Barlow area was an obvious solution.

First-of-a-kind solution

In 1967 the land was bought by the Central Electric Generating Board (CEGB) which began the construction of Drax Power Station. One of the early challenges it faced was how to minimise the environmental impact to the surrounding countryside.

In particular, it needed a solution for the tonnes of ash that came from the burning of coal fuel, which included both pulverised fuel ash (PFA) and furnace bottom ash (FBA). The answer was a first-of-a-kind: build a mound using the materials.

Construction on Barlow Mound began in 1974. First the existing top soil was removed and preserved for later use, drains were added and then a layer of FBA was laid.

Next conditioned PFA was added and moulded to suit the original design, never reaching higher than 36 metres. At this height the mound would visually obscure the power station from the neighbouring houses.

The final step was to seal the mound with a polymer and then reintroduce the top soil before grass, trees and hedgerow were planted. The trees and plants had been carefully tested to ensure that their roots wouldn’t interfere with the ash and compromise the integrity of the structure.

Roe deer walking in grass field

An ecologically important area

As time has passed and Drax Power Station has produced more ash, the mound has developed and grown. More than 301 million m3 is stored in the current site – more than the capacity of three million double decker buses.

In addition to the 100 species living on the site, a tenant farmer works 20 fields and a swan rescue and wildlife hospital rehabilitates up to 2,000 birds a year. More recently, the Skylark Centre and Nature Reserve has now opened up the area to the public to explore walking trails and see the nature first-hand.

Barlow is an area that has changed consistently since 1086. From the North’s early beginnings as an agricultural hub and Anglo-Saxon settlement, to the necessity for large-scale power solutions and to the importance of preserving local ecology, Barlow is an area that has been characterised by the outlook of the country.

Like Drax Power Station, to which it is intrinsically linked, Barlow Mound is a part of the Northern Yorkshire landscape – literally and figuratively.

What does an Instrument Craftsperson do?

Instrument Craftperson in action

How do you go about fixing a turbine that, on a normal day, spins 3,000 times every minute? The first port of call is to call in someone like Alice Gill, an Instrument Craftsperson at Drax Power Station. 

What does an Instrument Craftperson do?

What I do is maintain and repair the equipment that links the outside power plant and the control room – equipment that tracks temperature, levels or positioning that then informs our operators in the control room what’s happening on the plant.

Things like an oxygen analyser. It’s a probe that sits in the boiler and monitors the oxygen level so the operator can ensure the correct ratio of fuel to air is going into the boiler to reach optimum combustion.

I might be called on to do calibration checks on that sensor to ensure that it’s working properly. Or I might be asked to completely remove it and then to repair it.

How did you come to be doing this job?

I’m not the sort of person who likes to sit down at a desk all day – I’m more of a hands on sort of person. My dad was always working and fixing things in the garage at home and I liked being in there with him.

When I was at school I decided I didn’t want to go to university so started applying for apprenticeships and looking into engineering opportunities. Drax was one of those schemes and was the one I most wanted to be selected for – luckily enough I was offered a place.

The apprenticeship was four years and there are loads of training courses and so much to learn, including hands on experience and working in the plant.

I remember first arriving to the power station and not really believing the scale of the place. You think, ‘How am I ever going to find my way around?’, but you soon get used to it and it becomes the norm.

In September I became a full Instrument Craftsperson so now I can really get stuck in.

Alice Gill at Drax Power Station

“I’m not the sort of person who likes to sit down at a desk all day – I’m more of a hands on sort of person.”

What sort of challenges do you face?

Over the summer I’ve been doing a lot of work on the turbines. It’s a big job as they’re one of the most important elements driving the plant and generating the power. During outages the whole thing gets overhauled and given a full health check.

The turbine team needs to get into machinery, which is densely constructed and put together, so it’s my job to go in and carefully remove instrumentation so they can access it. When they’re done, I have to go back in, refit everything and check it’s all working again.

How do you do that?

When you’re removing the instruments it’s a bit more of a ‘just get it off’ approach – you just make sure you get it off safely without damaging it.

Then when we’re refitting it, we’re out there with our multimeters making sure we’re setting different probes at the right voltages and that everything is calibrated correctly.

There’s a screen in our workshop we use to watch the activity of the turbine so we can see the speed of the turbine creeping up as they switch it back on. It’s always a big moment. You know things are going to be alright because you’ve done everything, but there are still some nervous people in the room. The turbines are spinning at 3,000RPM so you really need it all to be working properly.

Is there anything that could wrong on an average day?

One of the biggest things that could go wrong in my area is the potential to trip an entire generating unit. It might be that you over-pressurise something or you accidentally trigger a switch that then sets off a daisy chain of events that ends up in a unit tripping. Tripping is where the unit turns off which basically leads to a total shutdown in electricity generation from one sixth of Drax Power Station.

There’s something called the 660 club – at full load the units are operating at 660 MW so if you trip one you enter into this infamous club. There are a few guys in the 660 club but thankfully I haven’t joined! When operating at full load of 660 MW, our units supply the National Grid with around 645 MW– enough to power an entire city.

What do you do outside of work?

I’ve got a horse called Red – I’ve had him for seven years but I’ve been riding since I was eight. It’s quite different to working with things that do exactly what you tell them. When you get on the horse he just does what he wants – he’s got a mind of his own. It’s a big change!

The turbulent history of coal

Aerial view of coal field

**9 May 2019 update: we have updated this story to mark the new GB record of continuous coal-free hours since 1882**

3490 BC

Households in China work out how to use coal for heat. The coal was bulky to transport, so settlements near forests probably burned it less often than wood.

4th century BC

Greek scientist Theophrastus makes a reference to coal as a fuel in his treatise, ‘On Stones’.

2nd century AD

By the 2nd century AD, the Romans were using coal from most of the main coalfields in Britain. Archaeologists have found flint axes from before the Roman era still embedded in coal. There is evidence that at this time people dug up coal on beaches then followed the seam of coal inland, encouraging them to investigate more sophisticated ways to mine it.

First millennium

Although it’s hard to date them precisely, early mines called ‘bell pits’ – deep holes which tapered outward at the bottom like a bell to provide a bigger surface area for mining – began to appear in the early part of the first millennium. These were lit by large candles burning animal fat and were dangerous: rocks could fall onto the miners and sometimes the pit would collapse entirely.

13th and 14th centuries

Room and pillar mines emerged as larger, more sophisticated versions of bell pits. In these pillars of coal were left standing to support the roof.

16th century

From the 1500s, mining expanded significantly. At this time coal was mostly used for heat by less well-off people. One observer wrote in 1587 that old men told him about “the multitude of chimneys lately erected, whereas in their young days there were not above two or three, if so many, in most uplandish towns of the realm.”


Great Britain was producing 2.7 million tonnes of coal per year, mostly for use in metal production.


In just half a century Britain ramps up coal production: it was producing 4.7 million tonnes of coal per year.

1763 to 1775

James Watt develops his steam engine, which was used to drain mines. Despite this, flooding remained a problem.


By the turn of the nineteenth century, Great Britain was producing 10 million tonnes of coal, driven by the rising demand of the Industrial Revolution. From about 1800, miners began to leave timber supports in place to hold up the roof of their pits, allowing them to follow coal seams deep into the earth. This was known as longwall mining.


Sir Humphrey Davy invents his safety lamp. It had a wire gauze around it so the flame would not encounter any gas and cause explosions. It became known as “the Miners’ Friend”.


Great Britain was producing 50 million tonnes of coal.


The world’s first steam driven power station was built on coal at Holborn Viaduct in London. It had a 27 tonne generator, enough to light 1,000 lamps. Later it was expanded to power 3,000. A second coal-fired power station opened later that year in the United States at Pearl Street Station in New York City. It initially served a load of 400 lamps and 82 customers but by 1884 it was powering more than 10,000 lamps.


Great Britain was producing 250 million tonnes of coal.


All Great British coal mines were nationalised (bought by the government) and placed under the control of the National Coal Board.


After the Selby coalfield was discovered in 1967, Drax Power Station was opened.

coal locomotive on rail tracks


Drax became the first coal-fired power station to install flue-gas desulphurisation technology, which removes 90% of coal’s harmful sulphur dioxide (SO2) emissions.


From the eighties onwards, many coal mines closed and in 1994, British Coal (the successor to the National Coal Board) was privatised.


As a result of UK mine closures and proposed emissions regulations coming into force from 2008, power stations started to increase the amount of coal they imported. Drax Power Station’s supply was initially split between 50% indigenous coal and 50% imported. There was a steadily increasing emphasis on imports for the decade thereafter.


The Large Combustion Plant Directive (LCPD) came into force across the EU, limiting emissions of SO2, NOx and particulates.


The Drax team successfully adapted the boilers of the plant to combust wood pellets. This was proof that a coal-fired power plant could be converted to biomass.

March 2013

The White Rose carbon capture and storage (CCS) project was announced as one of two preferred bidders in the UK’s £1bn CCS Competition. This project looked to build a new 448 MWe coal-fired power station with CCS capabilities on the existing Drax Power Station site in Yorkshire. With CCS technology installed, the power station would be able to capture and safely store carbon emissions underground rather than releasing them into the atmosphere.

1st April 2013

The Carbon Price Floor was launched in the UK. A tax on carbon dioxide (CO2) emissions, it is designed to provide an incentive to invest in low-carbon power generation.

September 2015

Due to reduced renewable subsidies, Drax withdrew from the White Rose CCS project.

18th November 2015

The UK government announced its intention to close all unabated coal-fired power stations by 2025 and restrict their usage from 2023 to meet the challenge of climate change. Drax aims to end its reliance on coal even quicker. Drax CEO Dorothy Thompson has talked about the possibility, given the right support, to have all coal units taken off the Drax system by 2020, if not before.

25th November 2015

The UK government cancelled its £1bn competition for CCS technology.

18th December 2015

On this day the last large scale deep coal mine in Great Britain – Kellingley in North Yorkshire – closed. UK producers were struggling to compete with lower priced, lower nitrogen oxides (NOx) emitting coal from oversees.

1st January 2016

The Industrial Emissions Directive is enforced in the UK and the rest of the European Union, putting stricter limits on the amount of NOx emitted into the atmosphere. From this point on coal power stations can either limit their availability to generate electricity or invest to adapt their boilers and use emissions abatement technologies.

May 2016

Great Britain saw its first day generating electricity without using any coal since the opening of the first UK power station in 1882.

September 2016

Drax and other energy companies write to the UK government in support of maintaining, rather than scrapping, the Carbon Price Floor.

April 2017

The first coal-free 24-hour period on Great Britain’s electricity system since 1882.

April 2018

UK government minister Claire Perry announced Drax had joined the Powering Past Coal Alliance, just three days after Great Britain’s fourth 24 hours free from the carbon-intensive fuel.

May 2019

A new coal-free record for Britain’s electricity system of 8 days, 1 hour and 25 minutes.

Present day

Drax Power Station is Europe’s largest decarbonisation project. Four of its six electricity generation units now run exclusively on biomass – reducing carbon emissions by more than 80%. Currently 75% of its electricity per year is generated using renewable, rather than fossil fuel. The last two coal units could be turned off by 2023.

How do you build a dome bigger than the Albert Hall?

Drax dome being raised.

For decades the most iconic sight at Drax Power Station has been its large grey cooling towers, but that’s changing. Today the most striking image on the Selby skyline is four white domes, each larger in volume than the Royal Albert Hall.

These are Drax’s biomass storage domes, standing 50 metres high and holding 300,000 tonnes of compressed wood pellets between them – enough to power Leeds, Manchester, Sheffield and Liverpool for more than 12 days.

They’re an integral part of Drax’s ongoing transition from coal to renewable biomass electricity generation. But while biomass is a far cleaner source of energy than coal – reducing carbon emissions by more than 80% – it comes with its own challenges. A key one is storage. That’s where the domes come in.

The need for a new storage space

Storing coal is a relatively simple task. With some management by heavy vehicles to reduce the occurrence of air pockets, coal can quite happily sit outside in the rain and still work efficiently as fuel. Compressed wood pellets are different. If a wood pellet gets wet it can degrade and become unusable. The main reason to compress wood into high density pellets in the first place is to take its moisture content down, saving weight for transportation and increasing its efficiency as a fuel for power station boilers.

More than that, because the biomass pellets are made from wood – a living and breathing organic material – they have to be stored in sensitively calibrated environments to keep them in a safe and usable state. Each storage dome had to be carefully designed, engineered and constructed to ensure it was fit to maintain this environment.

Construction began back in 2013 and required a Drax engineering team working closely with Idaho-based Dome Technology and York’s Shepherd Construction. At more than 50 metres tall, they’re the largest of their kind in the world – a new approach to construction had to be considered.

There were three key steps involved in the build:

Blowing up a giant balloon

The first stage is to prepare the foundation which takes the form of a massive concrete circular ring beam. A giant PVC airform dome is laid out over the ring beam and inflated using fans that are about the size of a Doctor Who telephone box, to form the outside of the dome.

Insulating the inside

With the dome still air-inflated, a thin 15mm layer of polyurethane foam is sprayed to the inside, serving to both insulate the structure and provide purchase for the first layers of steel reinforcements.

Completing the shell

Once the first steel reinforcing grid is attached to the polyurethane, the concrete spraying process begins. The dome wall is built up to a thickness of up to 350mm by adding further layers of steel reinforcement grid and reinforced concrete.

An engineer at Drax spraying the inside of a biomass storage dome.

Under pressure

The challenge the team now face following construction is maintaining a safe atmosphere inside the domes. The pellets are stored inside the domes in vast quantities and weight, which collectively create high amounts of pressure. As the pressure builds up the pellets release oxygen, which can cause a build-up of heat, and potentially an explosion.

But by addressing the cause of the increase in heat – the oxygen – the team found they could limit the danger potential. The solution was a specially-designed system that releases nitrogen into the dome. The gas forms non-flammable compounds with the oxygen, which keeps the inside of the dome stable.

The Drax cooling towers are still visible in and around Selby. And while they’re still an essential part of the power station, emitting steam (not smoke) used in the generating process, they’re no longer its most iconic image. The four storage domes sitting beside them more closely represent the future of Drax: a renewable one built on biomass technology.

Drax biomass storage domes

Now that the domes have been built, find out how their atmosphere is controlled.


Protecting the UK’s power from cyberattacks

At the heart of all aspects of modern life is a common resource: electricity. We need it to power our homes and our devices, to do our jobs and increasingly with electric trains, trams and cars, to get from A to B. For that electricity to be generated we need power stations.

They’re a critical part of the UK’s infrastructure, and so for terrorists and foreign states that have much to gain from disrupting the country, electricity generators are an obvious target.

Drax Power Station is the UK’s largest, with the capability to generate enough electricity to power every home in the north of England. With this mantle comes a higher risk of security threats – notably cyberattacks. Protecting the plant from these attacks is not only essential for Drax’s business, but for the safety of the country.

The threat of cyberattacks

Cyberattacks exist in the digital space, but can have a very real and tangible effect on the physical world. Between 2007-10, a computer virus later called Stuxnet attacked the Iranian nuclear programme, damaging a number of the centrifuges – a key part of the nuclear manufacturing process. As a result, Iran was forced to decommission roughly 1,000 centrifuges.

In a separate attack, 35,000 computers belonging to the Saudi energy company Saudi Aramco were partially wiped and destroyed, disrupting Saudi Arabia’s ability to supply 10% of the world’s oil. Over the past few years the threat of malicious entities has only increased – an alleged nation state attack on Ukraine’s power grid in late December 2015 left thousands of homes without electricity.

Drax is not immune to similar attempts – every month, the security team investigates about 1,000 issues. On an average month, two of the 1,000 are judged to be serious enough to warrant further investigation.

This is where Darktrace comes in.

Identifying the threats 

Darktrace is an incredibly powerful system that identifies and deals with threats to Drax. It starts by getting to know you.

It learns every single device on the network, its speed of traffic, and the patterns of each user’s daily work behaviour. For example, if a user logs in to the work systems at 8pm but has never done so before, Darktrace will identify this behaviour and flag it as different from the norm.

Flagging each of these events depending on its assessed severity, it maps the devices into a graphic that looks like a galaxy of stars of different colours. Drax’s security team use this to see at a glance which devices need attention and action. 

The result is a view across the whole power station – both the corporate environment and our Industrial Control Systems. Those security experts can then see where there have been issues with password protection, software updates with errors, and where any breaches come from.

More importantly, they can see viruses infecting devices in real time. When the system thinks it might see one, there are three possible outcomes.

Ignore, Throttle, Kill

Once Darktrace identifies any abnormal activity that could be a threat, the system offers three options: ignore, throttle, or kill.

‘Ignore’ means allowing the system to continue as normal. This option would be used if the system flagged something as a threat which human investigation found was harmless.

The ‘throttle’ option is designed for a situation when a virus is affecting one part of the operation of one device, but shutting down the device entirely would disable a critical function. The ‘throttle’ option slows the affected part of the device down to a virtual standstill but allows the device to continue the rest of its operations while the system investigates.

‘Kill’ means removing the unit from the network immediately. If a machine behaves in a way that suggests it could be infected, it can be shut down almost immediately.

Every day, a live dashboard of variables is available to identify problems, investigate breaches, fix any infected devices and then rebuild those systems. It’s a daily schedule that not only ensures the power station can continue uninterrupted, but that the entire country can too.