Tag: careers

The people behind the power

Drax Group may have been built with Drax Power Station at its core, but today it’s a set of integrated companies, helping to change the way energy is generated, supplied and used, to build a better future.

At the heart of each part of the business – from creating the fuel to power the station’s boilers to managing the supply of electricity, gas and renewable heating fuel to customers – is people.

Here we meet some of those people working behind the scenes.

Robert Gatlin, Operations Supervisor, Amite BioEnergy, Drax Biomass

robert_bw“I was a student in the Process Operations Technology programme at Southwest Mississippi Community College and Drax came to the school to recruit new grads. They were introducing a new technology I’d never heard of and it sparked my interest.

“The idea of using biomass to produce electricity on such a large scale was fascinating, so I joined Drax Biomass in 2014. I was unaware biomass was being used to produce electricity – it’s very exciting to be part of something this big and cutting edge.

“One of the most interesting things I’ve discovered working here is the way moisture affects nearly everything in the pelletising process. We really have to work diligently to ensure our moisture levels are where they need to be in every stage of producing a pellet.”

Rachel Grima, Sustainability Analyst, Drax Group

rachael_bw“I’ve always wanted to work in renewable energy and I studied life cycle analysis during my degree. I started looking for jobs in renewable energy, and as the biggest generator of renewable energy in the UK, Drax was an obvious choice!

“Today my job involves assessing and interpreting sustainability data for all the biomass we use. Our team uses this data to assess if a supplier meets our sustainability policy and regulation.

“I’d never looked very much at transport emissions, so I find it really interesting. You can move 30,000 tonnes of wood pellets in one ship, but it would take over 1,000 trucks to move that many, creating far more greenhouse gas emissions. Since joining the team, I’ve been really surprised to see how driving small efficiencies in a supply chain can create real savings in greenhouse gas emissions.”

Stephen Wilkinson, Turbine Maintenance Technician, Drax Power Station

Stephen Wilkinson, Turbine Maintenance Technician
I’ve always enjoyed building and fixing things. Given that my father and both grandfathers were in engineering – one of them even working at Drax during its construction – I had a strong drive to get into engineering. Living locally, it seemed the biggest and best place to work.

“I’m a Turbine Maintenance Technician, so I act as the link between the turbine support group and the main station planning and maintenance teams. I start the day early by looking through the list of overnight defects, focusing on the turbine area. After this I’m out of the office having a look at the issues to determine whether the station maintenance team or the turbine support group will carry out the repair work. From this point on every day is different.

“The recent changes Drax has made to adapt to a rapidly changing energy market has affected most people at the station. For me, seeing the major turbine upgrades take place has been extremely interesting. I started as an apprentice and then as a fitter, working on the turbine outages, seeing these upgrades first-hand. This has moved on to the point where I have been lucky enough to visit a number of the turbine manufacturing facilities in the UK and Germany.”

Gemma Baker, SME Customer Service Delivery Manager, Haven Power 


“I joined Haven Power in July 2007 as a Customer Service Advisor. I’d never worked in the energy industry before and thought it sounded interesting – Haven caught my eye as it was a new company which excited me. Being part of and contributing to a growing company was right up my street!

“Now I’m responsible for delivering a consistent and valued account management service to our electricity customers across all the small- to medium enterprise (SME) segments. This includes everything from billing and cash collection, to renewals and query and complaint resolution. I’ve been at Haven for nine and a half years now!”

Sam French, Customer Service Administrator Apprentice, Opus Energy


“Before joining [Opus Energy] I didn’t know anything about the energy industry – now I know about different supplier competitors, how an electricity supply contract is agreed and registered, and how we actually apply for a supply. I’ve learnt so much about different aspects of the energy industry, too.

“I haven’t had that much involvement with the Drax Group yet, but I’ve enjoyed looking into the business. I’ve found it really interesting to learn how they’ve managed to transition from a non-renewable company to one that is now producing more renewable than fossil fuel power – which is amazing.”

Amy Carton, Sales and Marketing Executive, Billington Bioenergy


 “I’m responsible for all aspects of internal and external marketing and communications at Billington Bioenergy, a company which supplies wood pellets to commercial and domestic customers who use them to heat their homes or businesses.

“I try to be environmentally conscious and keep my carbon footprint as low as possible – renewable and sustainable heating comes into this. It’s wonderful to spend my days promoting the merits of renewable heating. It’s a relatively small industry in the UK in comparison to our European counterparts, but this makes what we do here in Billington Bioenergy quite unique.

“There was quite a bit of information to digest when I first started – for example, ENplus regulations, different types of pellets, how wood pellet boilers work… it was a big learning curve!”

Find out about careers and apprenticeships within Drax Group:

Getting more from less

Luke Varley

“What can we do to ensure plant integrity, increase plant efficiency and ultimately get more megawatts out of the door for less?” This is a question at the heart of Luke Varley’s work.

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

But as the UK’s largest power station, it’s a site that needs to run all the time – any maintenance needs to fit around that consistent operation. For the most part this happens in the summer months, when electricity demand is lower and parts of the station can be temporarily shut down to carry out repairs. Even though Varley recognises there’s a large cost involved in shutting part of the plant down, it leads to longer term gains.

“We’re taking on work to improve efficiency, because the end result is we’re using less fuel to get more electricity,” he says. A small percentage increase in biomass efficiency can represent huge cost savings, he adds.

But as a relatively new fuel, biomass – in Drax’s case compressed wood pellets – presents a unique challenge for the engineers working with it.

Luke Varley

The biomass challenge

In the days when Drax ran only on coal at full load as part of a stable national grid, turbine maintenance meant facing common problems. “Where we had problems which were familiar from one hundred years of turbine history, we knew what to look for,” Varley explains.

But now the plant generates within a far more demanding network that needs flexibility and produces more than half its power using compressed wood pellets, there’s a need for greater efficiency – it means more innovative thinking and new challenges.

For example, most plants in the industry take each turbine offline to maintain it every eight-to-ten years. But using wood pellets means the turbines need to be as efficient as possible, and this means more regular inspections.

“Every four years we go back, overhaul the module and maximise its efficiency again. That’s new to the industry within the UK. Nobody else is doing that,” he says.

Despite the challenges, Varley isn’t fazed. “The technical and management challenges, they both come with experience,” he explains. His engineering experience began before his start at Drax.

“As a sixteen-year-old I walked out into the turbine hall and looked down and thought, ‘this is a different game.’”

Destined for grease

“My dad’s been in engineering all his life. He’d be building a car and I’d be dragged to a scrap man to help take an engine block out of an old car so he could use it at home,” Varley says. “I was destined to always be covered in grease.”

So when it came to beginning his career, Varley was set on what path he wanted to take. Two options presented themselves: working as a trainee draftsman in an air conditioning company or taking an apprenticeship with National Power. An early visit to Drax helped make his decision.

“Even though I’d been around engineering with my dad, as a sixteen-year-old I walked out into the turbine hall and looked down and thought, ‘this is a different game.’” He took the apprenticeship which led him to a number of power plants, but the impression of the Drax turbine hall never left him.

Drax Turbine Hall

“Later in my career I spent a lot of my time going around different power stations, and in grandness and scale I’ve never come across anything that matches what we’ve got at Drax. So when this job came about and I was asked to join, I said, ‘Sounds good to me.’”

Today, his position of getting more megawatts out of the door for less whilst ensuring safe operation of the plant is one that comes with a lot of responsibility and is built on a long history.

“The guy who was doing this job before me took a lot of pride in it. He used to say, ‘I’ve been here man and boy, I was even here when it was built and I wouldn’t have retired until I knew it was in safe hands.’”

Varley says, “I suppose that’s the best recognition I could get, really.”

The problem solver

Adam Nicholson

“One of the things I like about my job is working through the challenges we get on a daily basis and finding a solution,” explains Adam Nicholson, Process Performance Section Head at Drax Power Station.

That eagerness to find solutions makes him the ideal candidate for his current job: managing day-to-day improvements at Drax. “I’m responsible for the team which ensures the plant operates at optimum efficiency,” he says. His team make 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.

“It’s ultimately what I became an engineer for,” he says, “to follow that problem-solving thirst through.”

Earlier in his career, Nicholson was involved in one of the plant’s biggest problem-solving missions: converting it from running exclusively on coal to also run on compressed wood pellets. It was a unique test – one that required starting from scratch. There wasn’t a bank of existing knowledge that Nicholson and his fellow engineers could call upon.

“We did a lot of testing to learn more about the fuel,” he explains. “We had to understand how to get it to the boiler, how to process it before we put it in, how to convert the mills, and then how exactly the combustion would work.”

Some of that learning involved experimenting with unorthodox solutions to complex problems.


The dog tunnel

“One of the big problems with biomass is you can’t expose it to as high a temperature as you can coal,” Nicholson explains. This presented a challenge when it came to pulverising it.

Before fuel at the power station can be combusted, a set of mills pulverises it into a fine powder using a ring of rotating, heavy-duty balls. This fuel powder is then dried inside the mill with a mix of hot air drawn from the boiler house and cool air. But a fundamental difference between coal and biomass meant this process had to change.

“With coal the air can enter the mills at about 300 degrees. With biomass, if you get much above about 180 degrees, the biomass will set on fire,” says Nicholson. As part of the R&D phase he needed to work out a way to cool the mills down on a temporary basis. “We all took a big gulp and thought, ‘how are we going to do this?’”

Part of the problem was the existing ducts weren’t big enough to deliver enough cool air to the mills to lower their temperature to a safe range. Nicholson improvised a solution. “It was known as the dog tunnel,” he says.

If he could get a temporary, larger air supply to the mills it could provide more cool air and lower the overall temperature, allowing the testing to be conducted. So he found a company that could supply industrial flexible ducting, which he connected to a larger cold air duct and then fed through to a mill to deliver more cool air. As its informal name suggests, the result didn’t look like much, but it worked.

“It didn’t look like a finished solution, but the theory behind it was sound. For occasions like this we had to think, ‘let’s just do it, prove it, and then we can work on a permanent solution.’”

“That’s ultimately what I became an engineer for. To follow that problem-solving thirst through.”

The next challenge

Now the power station is successfully producing more than half of its electricity from biomass, Nicholson’s day-to-day responsibilities lie in ensuring safe operations and driving process efficiencies. To do this he keeps tabs on the combustion process – for example, by using thermal imaging cameras to monitor the inside of the furnace – and tweaks it to get as much energy as possible from the biomass fuel.

But at a site as large and complex as Drax there will always be new engineering challenges that require inventive thinking.

“Often you don’t know how you’re going to do something until you do a bit more work and try and understand the problem,” Nicholson says. “We’re nowhere near the end of our learning curve.”

Taming the electric beast

Gareth Newton

“It’s like a living animal, is Drax. It will break, it will fail, it will need maintenance,” says 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.

On top of the teams

“I’ve got a team servicing the filter fans. I’ve got a team doing a filter change on a biomass unit. Then I’ve got another company doing a pipework replacement on a discharge line for me. Somebody else is doing a service on the belt cleaners,” Newton says, listing half a typical day’s responsibilities. On any given day, he oversees a number of different teams that carry out a variety of maintenance tasks, and more often than not that list is a long one.

He’s a part of the Materials Handling team who deal with all the material arriving and leaving the power station. This includes the biomass and coal fuel coming in, and the ash, gypsum and other byproducts from the generation process going out.

It means he has a hand in the maintenance of almost all parts of the plant, from the compressed wood pellet storage domes to the boiler. With such a broad perspective of such a complex plant, he knows it’s not always the things you expect to fail that need fixing.


Monitoring the machine

“It’s a machine – it’s being used. It’s not a showpiece or something in a museum. It’s real and every now and then it will throw a gear out and stop,” he says. Those failures don’t always happen to a schedule, so when something does go wrong it can be unexpected.

“You might have a £50,000 gearbox sat in the stores ready and waiting to replace a faulty one, but it will be the £10 probe on a conveyer belt you never thought would break that fails and holds the whole system up,” he says. When something like that happens, he adds, it’s not always about having the exact tool that can fix it right there and then, it’s about thinking out of the box.

“The biggest part of this job, and I think it’s one of the biggest parts of heavy industry engineering, is not fixing or modifying things with what you’ve got,” he says. “It’s about using what you haven’t got to try and engineer your way out.”

He continues: “If you haven’t got a tool or part that you need, can you make something new, can you find a way to make it work? Or, do you even need it?”

“It’s like a living animal, is Drax. It will break, it will fail, it will need maintenance.”

Keeping your hands dirty

Newton grew up around engineering. His father ran a salvage yard and precious metals business and would bring back broken bits of machinery for the kids to fix as toys. “I’ve always had dirty hands,” he says.

It’s something that’s stuck with him. Today, even though he now spends a large proportion of his time monitoring jobs at a computer or moving between teams, it’s the practical side of the job that keeps him interested. “The best part of the job is working with your hands.”

And even though the demands of the living animal that is Drax can sometimes keep him on site longer than his working hours, it’s a beast he’s happy to look after.

“It’s a job you either love or hate. If you didn’t enjoy the engineering side you probably wouldn’t like it because there’s a lot of ingenuity and thinking on your feet needed,” he says. “But there are a lot of jobs out there that I wouldn’t want.”

The toolmaster

Andrew Storr

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

“When I was at school in Selby they were building the second half of the station,” he says. “We could see them building the cooling towers out of the classroom windows.”

But it wasn’t until a careers advisor brought an old cine film of the power station into class that he considered working there. “Part of the film was them stripping the turbine and I watched it and thought, ‘I want to do that,’” he says.

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.

“If the turbine’s off, forget the rest of it: we’re not generating electricity ,” he says. “We’ve got to make sure the turbine and the generator are absolutely as bulletproof as possible because we’ve only got one per unit.”

Considering the conditions each one comes under, this is no easy task. “The turbine shaft weighs 300 tonnes and spins at 3,000 rpm. The high pressure turbine is 165 bar, and temperature-wise, the steam running through it making it spin is 565 degrees centigrade.”

Bulletproof is an understatement. When it comes to carrying out maintenance on a turbine, it’s more than likely you’ll have to visit Storr’s workshop.


Fixing the governor

The workshop hasn’t always been there. It all started fifteen years ago when a piece of equipment broke. It was a turbine governor relay, a  precision hydraulic actuator that keeps the turbine spinning at the right speed. Drax needed a new one.

“They’ve got to be 100% reliable,” Storr explains. “If they lose control of the turbine, it can either come to a grinding halt or speed up too much and self-destruct.”

The team went in search of a replacement, contacting a manufacturer who came back with a sky-high quote. But Storr’s boss at the time had another idea.

He asked whether Storr could reverse engineer a full set of governor relays. “I made the fatal mistake of saying, ‘Yeah!’ So I set off with a few photographs and a handful of sketches,” Storr explains.

What followed were sleepless nights and a lot of grey hair, but in the end he managed to reproduce a full set that cost nearly half of the original quote. Better than that, they worked perfectly.

“Today, they’re on Unit 5, doing the business.”

Building the workshop

Manufacturing the governor relays was a turning point. Storr and the team saw there could be further savings and benefits if they did more manufacturing or refurbishment in-house. They had the staff capable of doing it, they just needed the facilities.

Although there was some initial scepticism from some in the company, Drax armed Storr with a small budget and he set out on building the workshop. That was 15 years ago. Back then, the workshop was designed to only refurbish equipment, but it has since grown. Now they can manufacture, too.

Today, when Drax buys in equipment which is either very expensive or lacking in quality, Storr’s team can modify it, make it fit better, last longer, or improve its efficiency without sending it away from the plant and incurring extra costs.

“We’re reaping the rewards. We’re leagues in front of everyone else in the UK because we’ve got our own manufacturing and machining facility,” Storr says. “We can do all this work on site. We’re not relying on other people.”

The workshop has given Drax an edge when it comes to its engineering ability, but Storr remains modest about the achievement.

“The thing is,” he says, “I’ve got a good boss and he will support you. But I do see it as a bit of a feather in my cap.”

The life of an electrical engineer

Gary Preece

A station like Drax doesn’t run itself. Its six turbines generate nearly 4,000MW 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.

“It doesn’t get much bigger than Drax. You need to be at the top of your game, every day,” says Lead Engineer Gary Preece.

A man at the top of his game is a fair way to describe Preece. He has been an electrical engineer almost his entire life. Beginning as an apprentice working at the Liverpool dockyards at age 16, Preece has worked a range of increasingly demanding projects and roles, including engineering consultancy and work for the Royal Navy on their Type 26 Global Combat Ship, where he was in charge of designing the on-board power infrastructure.

He became a member of the Drax team five years ago.

Life on the job

“On a station the size of Drax, you don’t have a typical day. There are just too many systems that can change status, that can fail, or that require immediate attention to remain operational. It’s never-ending,” Preece says.

Working as an electrical engineer in a plant the size of Drax doesn’t just mean getting called down to help out when a fuse blows. His responsibilities as lead engineer encompass a broad range of functions.

“There’s lots to do. There’s a lot of hands-on work, but there’s also a lot of study work.” Tasks can include scoping out, planning and budgeting new projects, working with contractors and suppliers, fault analysis and power level studies.

This last role is what Preece has come to like most about the job – working with sophisticated computer simulations to model output and crisis scenarios, all so Drax can operate at its optimal level with National Grid.

“I really enjoy a lot of the theoretical work,” he says. “We can do so much with this software.”

Of course, there are times when he does have to fix things. And in a power plant, mistakes can have major consequences. “The energy levels in a power plant are so high that when something fails, it usually fails spectacularly.”

This means Preece needs to be on call all day and all night. If there’s a technology failure, he needs to be on the site, finding out what went wrong and directing recovery efforts. “There’s no hiding place. If something goes wrong, you have to fix it.”

Transforming Drax’s electric infrastructure

Sometimes individual projects can occupy all aspects of Preece: engineer, thinker and planner.

One of the most challenging was when Drax wanted to import a largely unused industrial generator transformer unit from Kent to the station in Yorkshire.

The transformer was split into three 200-tonne components. Before transit, Preece and his team conducted extensive checks on the components and oil (transformers contain oil to insulate the coil), to evaluate the state of the machinery. And these steps had to be repeated after every stage of the journey, to ensure no damage had been sustained.

After checks were completed, the units needed to be transported via the M25 motorway to ports in the south of England, from which they would travel by ship on the North Sea, ready to be unloaded and transported to Drax for installation.

However, the team hit complications, this time with the Highways Agency. “The structures were so heavy, that we had to take a ferry from a different port because authorities were worried the bridges we were planning on using to get there wouldn’t take the weight of the units. We had to do a turnaround in the middle of the motorway!”

Getting the extra transformers installed gave the plant some important breathing room in the unlikely event of a failure. “Some power stations don’t have spares. If there was a failure, they could be out of commission for months,” says Preece.

For a power station as large as Drax, that would be disastrous. But even with the extra transformers on site, the number of ways the electrical infrastructure at a power plant can go wrong is huge. That’s why experienced engineers like Preece are as indispensable as the machinery itself.

“Drax is one of the best opportunities you’re going to get for artistic licence. It doesn’t get much bigger.”

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!

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.


Summer in the station

Biomass domes

Bees buzz and heat haze fizzes on the tarmac. It’s summer, and since the days are warm and long, demand for electricity sinks as lights are left off and life is lived outdoors.

Electricity demand is lower, so the assumption would be that activity at the UK’s power stations is minimal. The reality however, is far different.

Instead, the fall in demand is an opportunity to perform crucial maintenance work – to upgrade and extend the life of power stations across the world.

In many ways, summer in the station is the busiest time of the year.

Slowing the beating heart of the country

To get up close and personal with the equipment and carry out major repairs, large sections of the power station need to come offline – this is a procedure called an outage. At Drax Power Station there are six units, which together supply around 7-8% of the UK’s supply. Taking one offline is a big project, but a necessary one.

“Many years ago we use to do a mixture of major and minor outages but we have reconfigured the outage cycle, so all we do now are major outages. Now, we run a schedule where each unit has an outage every four years,” says Andrew Squires, Outage Manager at Drax.

This year each of our six units have come offline – five outages have already been completed and one is set to be back in service at the beginning of November. With two of these being major outages and the other four taken off the system for essential high pressure (HP) Turbine module repair works.

To ensure this all operates smoothly, planning starts early. The process starts a minimum of a year in advance, during which time scoping, planning, parts and materials are ordered for the outage. It’s a necessary advance, given the challenging timescales, projects and numbers of people that are needed to carry out the work required.

Calling in the helping hands

Drax drafts in engineering contractors in large numbers to carry out the huge scale of work required to shut down and maintain units at the power station. 2016 was a particularly busy year – at peak points 3,500 people were on site carrying out the work. “It’s a number we’ve never seen previously,” Squires says.

Main projects delivered during the outage timescale in 2016 include changing the Generator Stator core, Generator Transformer, Oil Burner system and HP Turbine module. The Main Steam pipework replacement being the largest of all, this pipework runs from the Boiler to the Turbine and is the first time this had been done in the lifetime of the plant. Now complete, this is set to last the life of the station.

Engineering work happening at Drax Power Station

Industry pioneers

Drax uses compressed wood pellets in three of its six units and this pioneering step brings implications for how they’re maintained. In the industry it’s a whole new challenge for which Drax engineers are still writing the rulebook. “We’re understanding the engineering implications of using biomass in our boilers, and developing strategies for maintenance,” says Squires.

As Europe’s largest decarbonisation project, maintaining and consistently learning comes with the territory. It’s just another challenge for the team to tackle during summer in the station and beyond.