Tag: Drax Power Station

Breaking circuits to keep electricity safe

6 March 2020

Power generation
Electric relay with sparks jumping between the contacts doe to breaking a heavy inductive load.

Electricity networks around the world differ many ways, from the frequency they run at to the fuels they’re powered by, to the infrastructure they run on. But they all share at least one core component: circuits.

A circuit allows an electrical current to flow from one point to another, moving it around the grid to seamlessly power street lights, domestic devices and heavy industry. Without them electricity would have nowhere to flow and no means of reaching the things it needs to power.

But electricity can be volatile, and when something goes wrong it’s often on circuits that problems first manifest. That’s where circuit breakers come in. These devices can jump into action and break a circuit, cutting off electricity flow to the faulty circuit and preventing catastrophe in homes and at grid scale. “All this must be done in milliseconds,” says Drax Electrical Engineer Jamie Beardsall.

But to fully understand exactly how circuit breakers save the day, it’s important to understand how and why circuits works.

Circuits within circuits 

Circuits work thanks to the natural properties of electricity, which always wants to flow from a high voltage to a lower one. In the case of a battery or mains plug this means there are always two sides: a negative side with a voltage of zero and a positive side with a higher voltage.

In a simple circuit electricity flows in a current along a conductive path from the positive side, where there is a voltage, to the negative side, where there is a lower or no voltage. The amount of current flowing depends on both the voltage applied, and the size of the load within the circuit.

We’re able to make use of this flow of electricity by adding electrical devices – for example a lightbulb – to the circuit. When the electricity moves through the circuit it also passes through the device, in turn powering it. 

A row of switched on household electrical circuit breakers on a wall panel

A row of switched on household electrical circuit breakers on a wall panel

The national grid, your regional power distributor, our homes, businesses and more are all composed of multiple circuits that enable the flow of electricity. This means that if one circuit fails (for example if a tree branch falls on a transmission cable), only that circuit is affected, rather than the entire nation’s electricity connection. At a smaller scale, if one light bulb in a house blows it will only affect that circuit, not the entire building.

And while the cause of failures on circuits may vary from fallen tree branches, to serious wiring faults to too many high-voltage appliances plugged into a single circuit, causing currents to shoot up and overload circuits, the solution to preventing them is almost always the same. 

Fuses and circuit breakers

In homes, circuits are often protected from dangerously high currents by fuses, which in Great Britain are normally found in standard three-pin plugs and fuse boxes. In a three pin plug each fuse contains a small wire – or element.

One electrical fuse on electronic circuit background

An electrical fuse

When electricity passes through the circuit (and fuse), it heats up the wire. But if the current running through the circuit gets too high the wire overheats and disintegrates, breaking the circuit and preventing the wires and devices attached to it from being damaged. When a fuse like this breaks in a plug or a fuse box it must be replaced. A circuit breaker, however, can carry out this task again and again.

Instead of a piece of wire, circuit breakers use an electromagnetic switch. When the circuit breaker is on, the current flows through two points of contact. When the current is at a normal level the adjacent electromagnet is not strong enough to separate the contact points. However, if the current increases to a dangerous level the electromagnet is triggered to kick into action and pulls one contact point away, breaking the circuit and opening the circuit breaker.

Another approach to fuses is using a strip made of two different types of metals. As current increases and temperatures rise, one metal expands faster than the other, causing the strip to bend and break the circuit. Once the connection is broken the strip cools, allowing the circuit breaker to be reset.

This approach means the problem on the circuit can be identified and solved, for example by unplugging a high-voltage appliance from the circuit before flipping the switch back on and reconnecting the circuit.

Protecting generators at grid scale 

Power circuit breakers for a high-voltage network

Circuit breakers are important in residential circuits, but at grid level they become even more crucial in preventing wide-scale damage to the transmission system and electricity generators.

If part of a transmission circuit is damaged, for example by high winds blowing over a power line, the current flow within that circuit can be disrupted and can flow to earth rather than to its intended load or destination. This is what is known as a short circuit.

Much like in the home, a short circuit can result in dangerous increases in current with the potential to damage equipment in the circuit or nearby. Equipment used in transmission circuits can cost millions of pounds to replace, so it is important this current flow is stopped as quickly as possible.

“Circuit breakers are the light switches of the transmission system,” says Beardsall.

“They must operate within milliseconds of an abnormal condition being detected. However, In terms of similarities with the home, this is where it ends.”

Current levels in the home are small – usually below 13 amps (A or ampere) for an individual circuit, with the total current coming into a home rarely exceeding 80A.

In a transmission system, current levels are much higher. Beardsall explains: “A single transmission circuit can have current flows in excess of 2,000A and voltages up to 400,000 Volts. Because the current flowing through the transmission system is much greater than that around a home, breaking the circuit and stopping the current flow becomes much harder.”

A small air gap is enough to break a circuit at a domestic level, but at grid-scale voltage is so high it can arc over air gaps, creating a visible plasma bridge. To suppress this the contact points of the circuit breakers used in transmission systems are often contained in housings filled with insulating gases or within a vacuum, which are not conductive and help to break the circuit.

A 400kV circuit breaker on the Drax Power Station site

A 400kV circuit breaker on the Drax Power Station site

In addition, there will often be several contact points within a single circuit breaker to help break the high current and voltage levels. Older circuit breakers used oil or high-pressure air for breaking current, although these are now largely obsolete.

In a transmission system, circuit breakers will usually be triggered by relays – devices which measure the current flowing through the circuit and trigger a command to open the circuit breaker if the current exceeds a pre-determined value. “The whole process,” says Beardsall, “from the abnormal current being detected to the circuit breaker being opened can occur in under 100 milliseconds.”

Circuit breakers are not only used for emergencies though, they can also be activated to shut off parts of the grid or equipment for maintenance, or to direct power flows to different areas.

A single circuit breaker used within the home would typically be small enough to fit in your hand.  A single circuit breaker used within the transmission system may well be bigger than your home.

Circuit breakers are a key piece of equipment in use at Drax Power Station, just as they are within your home. Largely un-noticed, the largest power station in the UK has hundreds of circuit breakers installed all around the site.

A 3300 Volt circuit breaker at Drax Power Station

A 3300 Volt circuit breaker at Drax Power Station

“They provide protection for everything from individual circuits powering pumps, fans and fuel conveyors, right through to protecting the main 660 megawatt (MW) generators, allowing either individual items of plant to be disconnected or enabling full generating units to be disconnected from the National Grid,” explains Beardsall.

The circuit breakers used at Drax in North Yorkshire vary significantly. Operating at voltages from 415 Volts right up to 400,000 Volts, they vary in size from something like a washing machine to something taller than a double decker bus.

Although the size, capacity and scale of the circuit breakers varies dramatically, all perform the same function – allowing different parts of electrical circuits to be switched on and off and ensuring electrical system faults are isolated as quickly as possible to keep damage and danger to people to a minimum.

While the voltages and amount of current is much larger at a power station than in any home, the approach to quickly breaking a circuit remains the same. While circuits are integral parts of any power system, they would mean nothing without a failsafe way of breaking them.

End of coal generation at Drax Power Station

27 February 2020

Investors
Coal picker, Drax Power Station, 2016

Drax Group plc
(“Drax” or the “Group”; Symbol:DRX)
RNS Number : 2747E

Following a comprehensive review of operations and discussions with National Grid, Ofgem and the UK Government, the Board of Drax has determined to end commercial coal generation at Drax Power Station in 2021 – ahead of the UK’s 2025 deadline.

Commercial coal generation is expected to end in March 2021, with formal closure of the coal units in September 2022 at the end of existing Capacity Market obligations.

Will Gardiner, Drax Group CEO, said:

“Ending the use of coal at Drax is a landmark in our continued efforts to transform the business and become a world-leading carbon negative company by 2030. Drax’s move away from coal began some years ago and I’m proud to say we’re going to finish the job well ahead of the Government’s 2025 deadline.

“By using sustainable biomass we have not only continued generating the secure power millions of homes and businesses rely on, we have also played a significant role in enabling the UK’s power system to decarbonise faster than any other in the world.

“Having pioneered ground-breaking biomass technology, we’re now planning to go further by using bioenergy with carbon capture and storage (BECCS) to achieve our ambition of being carbon negative by 2030, making an even greater contribution to global efforts to tackle the climate crisis.

“Stopping using coal is the right decision for our business, our communities and the environment, but it will have an impact on some of our employees, which will be difficult for them and their families.

“In making the decision to stop using coal and to decarbonise the economy, it’s vital that the impact on people across the North is recognised and steps are taken to ensure that people have the skills needed for the new jobs of the future.”

Coal in front of biomass storage domes at Drax Power Station, 2016

Coal in front of biomass storage domes at Drax Power Station, 2016

Drax will shortly commence a consultation process with employees and trade unions with a view to ending coal operations. Under these proposals, commercial generation from coal will end in March 2021 but the two coal units will remain available to meet Capacity Market obligations until September 2022.

The closure of the two coal units is expected to involve one-off closure costs in the region of £25-35 million in the period to closure and to result in a reduction in operating costs at Drax Power Station of £25-35 million per year once complete. Drax also expects a reduction in jobs of between 200 and 230 from April 2021.

The carrying value of the fixed assets affected by closure was £240 million, in addition to £103 million of inventory at 31 December 2019, which Drax intends to use in the period up to 31 March 2021. The Group expects to treat all closure costs and any asset obsolescence charges as exceptional items in the Group’s financial statements. A further update on these items will be provided in the Group’s interim financial statements for the first half of 2020.

As part of the proposed coal closure programme the Group is implementing a broader review of operations at Drax Power Station. This review aims to support a safe, efficient and lower cost operating model which, alongside a reduction in biomass cost, positions Drax for long-term biomass generation following the end of the current renewable support mechanisms in March 2027.

While previously being an integral part of the Drax Power Station site and offering flexibility to the Group’s trading and operational performance, the long-term economics of coal generation remain challenging and in 2019 represented only three percent of the Group’s electricity production. In January 2020, Drax did not take a Capacity Market agreement for the period beyond September 2022 given the low clearing price.

Enquiries

Drax Investor Relations:
Mark Strafford
+44 (0) 7730 763 949

Media

Drax External Communications:
Ali Lewis
+44 (0) 7712 670 888

 

Website: www.drax.com/uk

END

Capacity Market agreements for existing assets and review of coal generation

31 January 2020

Investors
Drax's Kendoon Power Station, Galloway Hydro Scheme, Scotland

RNS Number : 6536B

T-3 Auction Provisional Results

Drax confirms that it has provisionally secured agreements to provide a total of 2,562MW of capacity (de-rated 2,333MW) from its existing gas, pumped storage and hydro assets(1). The agreements are for the delivery period October 2022 to September 2023, at a price of £6.44/kW(2) and are worth £15 million in that period. These are in addition to existing agreements which extend to September 2022.

Drax did not accept agreements for its two coal units(3) at Drax Power Station or the small Combined Cycle Gas Turbine (CCGT) at Blackburn Mill(4) and will now assess options for these assets, alongside discussions with National Grid, Ofgem and the UK Government.

A new-build CCGT at Damhead Creek and four new-build Open Cycle Gas Turbine projects participated in the auction but exited above the clearing price and did not accept agreements.

T-4 Auction

Drax has prequalified its existing assets(5) and options for the development of new gas generation to participate in the T-4 auction, which takes place in March 2020. The auction covers the delivery period from October 2023.

CCGTs at Drax Power Station

Following confirmation that a Judicial Review will now proceed against the Government, regarding the decision to grant planning approval for new CCGTs at Drax Power Station, Drax does not intend to take a Capacity Market agreement in the forthcoming T-4 auction. This project will not participate in future Capacity Market auctions until the outcome of the Judicial Review is known.

Enquiries:

Drax Investor Relations
Mark Strafford
+44 (0) 7730 763 949

Media:

Drax External Communications
Matt Willey
+44 (0) 0771 137 6087

Photo caption: Drax’s Kendoon Power Station, Galloway Hydro Scheme, Scotland

Website: www.drax.com/uk

Acquisition Bridge Facility refinancing completed

24 July 2019

Investors

Private placement

The £375 million private placement with infrastructure lenders comprises facilities with maturities between 2024 and 2029(2).

ESG Facility

The £125 million ESG facility matures in 2022. The facility includes a mechanism that adjusts the margin based on Drax’s carbon emissions against an annual benchmark, recognising Drax’s continued commitment to reducing its carbon emissions as part of its overall purpose of enabling a zero-carbon, lower cost energy future.

Together these facilities extend the Group’s debt maturity profile beyond 2027 and reduce the Group’s overall cost of debt to below 4 percent. 

Enquiries:

Drax Investor Relations:
Mark Strafford
+44 (0) 1757 612 491

Media:

Drax External Communications:
Matt Willey
+44 (0) 7711 376 087 

Website: www.drax.com/uk

Note

(1)  Drax Corporate Limited drew £550 million under an acquisition bridge facility on 2 January 2019 used to partially fund the acquisition of ScottishPower Generation Limited for initial net consideration of £687 million. £150 million of the acquisition bridge facility was repaid on 16 May 2019.

(2)  £122.5 million in 2024, £122.5 million in 2025, £80 million in 2026 and £50 million in 2029.

Meet the apprentices powering our future

4 March 2019

Sustainable business

“Different people do things different ways,” says Sam Stocks, an apprentice engineer at Drax Power Station. It’s a sentiment echoed by corporate administration apprentice Chloe Carpenter at Opus Energy. Asked to describe her role, she says, “[It’s] a very different kind of job.”

Chloe and Sam are just two of a number of apprentices at Drax Group who are working across the UK. And while they’re proud to do things differently, they do have something in common – they’re all hands-on, practical people who would rather get stuck in on a project than sit still and hear about it in the classroom.

“I chose an apprenticeship over higher education because I’m more of a doing person,” says Molly Fensome, a corporate administration apprentice. Sam agrees. “I like to be hands-on,” he says. “I don’t like being sat in a classroom.”

They are doing things their way – engineering their own futures while growing personally and professionally. And ensuring the future of our energy supply in the process.

Finding a strong sense of identity

For Sam, working at Drax wasn’t just a sensible career move, it was also following in his family’s footsteps. “My grandad worked in the power station industry all his life. [My family] know exactly what I’m like and they knew what type of place this was to work.”

Drax’s transformation from a coal-powered plant to a modern, sustainable electricity company means Sam’s work is building a power framework for future generations, while also paying homage to his grandad’s career.

Jake Dawson, an electrical engineer apprentice, followed a similar path into the power industry. Being born and bred in the area, Drax Power Station has always been a part of his geography. “Because I’m such a local lad it was perfect for me,” he says.

In his role, Jake can play a key part in the region where he grew up. A recent Oxford Economics report shows that Drax contributes £431 million to Yorkshire and the Humber economy and supports over 3,200 jobs.

A role in a team

Drax is a large organisation, but for Chloe finding role models within her team she can look up to and take guidance from has been easy. “Mentoring sessions are relaxed and you build a special bond with that person,” she says. “You can talk to them about work, outside of work – anything. They’ll always be there for you.”

Corporate administration apprentice Matt Donnelly has had a similar experience, adding that he’s seen his confidence grow, and feels he has made lifelong friends in his role.

Ultimately, it’s not just that they are given the right support, but that apprentices are integrated as a part of the company from day one. “My favourite part of my apprenticeship so far is being part of the team,” says Chloe. “Because you feel like you’re not just an apprentice, but you’re also one of them.”

Being part of something bigger

Sam remembers his first day at Drax Power Station: “It was overwhelming, you don’t actually realise how big it is and realise how many people work here. It’s just normal now, if I go anywhere else, I’m thinking, ‘That’s not as big as at work.’”

It’s not just its size that makes the UK’s biggest single site renewable power station stand out, but the potential for career development there. It’s this that Jake had on his mind when he first made the decision to become an apprentice. He was working in an unskilled job with little opportunity, but he knew he had it in him to find something bigger.

His outlook today as a Drax apprentice is very different. “My aim after the four years is to carry on growing as a person, increasing all my skills that I have, and maybe eventually becoming a supervisor or an engineer, who knows?”

This mindset of striving for better is evident across apprentices. It’s what drove them to join the programme in the first place. “Instead of going somewhere like uni and then possibly coming out without a job, you’ve got a job, and you’re actually learning as you’re doing it,” says Sam. “The skill set that I’ve learnt now – I’ll probably go anywhere in the world with it.”

Find out more about apprenticeships at Drax

How to switch a power station off coal

22 August 2018

Sustainable bioenergy
Turbine hall at Drax Power Station

In 2003, the UK’s biggest coal power station took its first steps away from the fossil fuel which defined electricity generation for more than a century. It was in that year that Drax Power Station began co-firing biomass as a renewable alternative to coal.

It symbolised the beginnings of the power station’s ambitious transformation from fossil-fuel stalwart to the country’s largest single-site renewable electricity generator. This plan presented a massive engineering challenge for Drax, with significant amounts of new knowledge quickly needed.

Fifteen years later, three of its generating units now run entirely on compressed wood pellets, a form of biomass, while coal has been relegated to stepping in only to cover spikes in demand and improve system stability.

Now Drax has converted a fourth unit from coal to biomass. This development represents the passing of a two thirds marker for the power station’s coal-free ambitions and adds 600-plus megawatts (MW) of renewable electricity to Great Britain’s national transmission system.

Building on the past

Drax first converted a coal unit to biomass in 2013, with two more following in 2014 and 2016. This put Drax in an interesting position going into a new conversion: on one hand, it is one of the most experienced generators in the world when it comes to dealing with and upgrading to biomass. On the other, it’s still relatively new to the low carbon fuel compared with its dealings with coal.

Adam Nicholson

“We’ve decades of understanding of how to use coal, but we’ve only been operating with biomass since we started the full conversion trials in 2011,” says Adam Nicholson, Section Head for Process Performance at Drax Power. “We’ve got few running hours under our belts with the new fuel versus the hundreds of man years of coal knowledge and operation all around the country.”

When converting a generating unit, the steam turbine and generator itself remain the same. The difference is all in the material being delivered, stored, crushed and blown into the boiler and burned to heat up water and create steam. And because biomass can be a volatile substance – much more so than coal – this process must be a careful one.

Drax could build on the learnings and equipment it had already developed for biomass such as specially built trains and pulverising mills, but storage proved a bigger issue. The giant biomass domes at Drax that make up the EcoStore are advanced technological structures carefully attuned to storing biomass, but for Unit 4, they were off limits.

Instead Drax engineers had to come up with another solution.

The journey of a pellet through the power station

Normally wood pellets are brought into Drax by train, unloaded and stored in the biomass domes before travelling through the power station to the mills and then boilers. Unit 4, however, sits in the second half of the station – built 12 years after the first. This slight change in location presented a problem.

“There’s no link from the eco store to Unit 4 at all,” explains Nicholson. “You can’t use the storage domes and that whole infrastructure to get anything to Unit 4.”

Drax engineers set about designing a new conveyor system that could connect the domes to the mills and boiler that powers Unit 4. After weeks of design, the team had a theoretical plan to connect the two locations with one problem: it was entirely uneconomical.

Rail unloading building 1 and storage silos

“If we were building a new plant it would be relatively easy, because you could plan properly and wouldn’t have existing equipment in the way,” says Nicholson.

“We had to plan around it and make use of the pre-existing plant.”

Within that pre-existing plant though were vital pieces of equipment, some of which had laid dormant since Drax stopped fuelling its boilers with a mixture of coal and biomass and opted instead for full unit conversions.

Drax began cofiring across all six units in 2003, using two different materials – a mix of around 5% biomass and 95% coal. A direct injection facility was added in 2005. It involved blowing crushed wood pellets into coal fuel lines from two of the power station’s 60 mills.

Then, the amount of renewable power Drax was able to generate roughly doubled in the summer of 2010 when a 400 MW co-firing facility became operational.

Back to the present day, it’s fortunate for the Unit 4 conversion that the co-firing facility includes its own rail unloading building (RUB 1) and storage silos. They are located much closer to the unit than the bigger RUB 2 and the massive biomass domes.

This solved the problem of storage but moving the required volumes of biomass through the plant without significant transport construction still posed a challenge.

Rail unloading building 1 and storage silos for Unit 4 [left], EcoStore biomass domes for units 1-3 [right]

To tackle this the team modified a pneumatic transport system, previously tested during co-firing, to have the capability to blow entire pellets from the storage facilities around the power station at speeds of more than 20 metres per second. The success of this system proved key – it was the final piece necessary to make the conversion of Unit 4 economical.

The post-coal future

Andy Koss

For now, Drax’s fifth and sixth generating unit remain coal-powered, but are called upon less frequently. With Great Britain set to go completely coal-free by 2025, there are plans to convert these too, but as part of a system of combined cycle gas turbines and giant batteries rather than biomass powered units.

It’s an opportunity for Drax to again leverage its pre-existing plant and provide the grid with a fast acting-source of lower-carbon electricity. As with converting to biomass, it will pose a complex new engineering challenge – one that will prepare Drax to meet the future needs of grid as it continues to change and demand greater flexibility from generators.

“The speed at which the Unit 4 project has been delivered is testament to the engineering expertise, skill and ingenuity we continue to see at Drax. We’re nimble and innovative enough to meet future challenges,” says Andy Koss, Chief Executive, Drax Power.

“We may look very different in 10 or 20 years’ time, but the ethos of that innovation and agility is something that will persist.”

Repowering the remaining coal plant with gas and up to 200 MW of batteries will sit alongside research into areas such as carbon capture, use and storage (CCuS) that is all geared towards expanding Drax Power beyond a single site generator into a portfolio of flexible power production facilities.

Unit 4’s conversion is more than just a step beyond halfway for the power station’s decarbonisation, but a significant step towards becoming entirely coal-free.

Find out more about Unit 4.

Drax: A rail history

5 July 2018

Power generation

Railways in Great Britain today are often seen as unreliable or chaotic, yet they remain a vital part of the lives of the population and the economy of the country.

When rail transport first arrived in earnest in the 19th century, it suddenly allowed goods from around the world, as well as people, to quickly cross the country. It reshaped perceptions of the country’s geography, unlocked the population and accelerated industries.

Over time, however, the role of the railways has diminished, owing largely to the massive rise in car ownership and the shifting of freight onto the road. But that is not to say it has completely lost its importance.

With 6,000 trains passing through Drax Power Station every year, rail is still integral to Drax and the region around it. In fact, since the very first introduction of the railways to the region it has played a major part in shaping the landscape.

A village with two stations

Before the construction of the power station or nationalisation of the railways, Drax village was well-connected, with two different railway lines running through it: the North Eastern Railway (NER) Selby to Goole line, and the Hull and Barnsley Railway’s Doncaster to Hull line.

Each of these lines ran through a different station with NER calling at Drax Hales Station while Hull and Barnsley called at Drax Abbey Station. But, following nationalisation and British Rail’s modernisation plans, Drax Abbey Station, which had closed to passengers in 1931, closed to goods traffic in 1959. Drax Hales Station followed suit in 1964 when it was closed as part of what became known as the Beeching Axe.

“British Rail chairman Richard Beeching famously carried out a review of Britain’s railways in the 60s and as a result closed vast quantities of – what he considered – uneconomical lines,” explains Andrew Christian, FGD & By-products Section Head at Drax Power Station and expert on the area’s history. “At that time oil was cheap, people were increasingly using cars and motorways were being constructed. Nobody really foresaw the rail demand that would be needed in the future to serve the power station.”

Daleks on a merry-go-round

In the 1960s and 70s, with the planning and construction of Drax Power Station underway, there was a new need for railways in bringing coal from the new Selby coalfield. This resulted in the reopening of a closed part of the Hull and Barnsley line for four miles from a reinstated junction at Hensall. Known as Hensall Junction it was renamed Drax Power Station Branch Junction and later shorted to Drax Branch Junction.

A rail system known as a ‘MGR loop’ was installed on the power station grounds, which allows trains to loop around the station and deposit coal – today also wood pellets – without stopping.

The ‘merry-go-round’ trains as they are known, were originally made up of 40, four-wheeled merry-go-round (MGR) hopper wagons. These were much smaller than the wagons that carry biomass from ports to power stations today, and more than 11,000 MGRs where built to serve coal power stations around Great Britain.

Photo by Andrew Brade, Railway Engineer at Drax Power Station

The open-topped wagons were each capable of carrying 33 tonnes of pulverised coal, which was automatically released thanks to a piece of machinery alongside the track colloquially known as ‘Daleks’ thanks to their resemblance to the Dr Who villain.

But as the power station began to change and evolved to fit the modern world, so too did the railway serving it.

Rail at Drax beyond coal

The original Drax rail loop was a single track, with three coal unloading points. By 1993 there was 14.5 km of track with 27 sets of points and crossings allowing trains to switch rails, thanks to the double tracked loop and extra tracks laid to serve traffic taking limestone in and gypsum out from the power station. This was further expanded with the introduction of biomass and a new double track and unloading facility in 2013.

The biomass trains are specially designed to keep compressed wood pellets dry and they are much longer than their MGR predecessors. At 18.2 meters long, their capacity is 30% greater than a coal wagon. It means the 23-wagon trains bringing biomass to the power stations from Tyne, Hull, Immingham and Liverpool’s ports are a quarter of a mile long.

It might be a far cry from the heyday in which the railways crisscrossed the region, but they remain a vital part of the area. And while the area’s original lines are now 50 years dormant, their remnants are still visible in the lasting impact they’ve left on the surrounding landscape.

Many of the embankments and bridges found in and around Drax stem from those first railway lines, while much of the A645 road that was constructed in the early 1990s runs along the track bed of NER’s route to Goole.

Photos by Andrew Brade, Railway Engineer at Drax Power Station

The trains might not stop in Drax Village anymore, but they remain a vital part of the landscape, and how it’s powered.

Northern Powerhouse Minister Jake Berry was in Yorkshire on 5 July 2018 to unveil the first Drax freight wagons with ‘Northern Powerhouse’ branding to deliver biomass to the power station. Read more.

The night shift

21 June 2018

Power generation
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.