Author: Alice Roberts

Maintaining electricity grid stability during rapid decarbonisation

13 November 2019

Power generation
Cruachan pylons

Great Britain’s electricity system is in the middle of a revolution. Where power supply was once dominated by some big thermal coal, gas and nuclear power stations, it now comes from an array of sources. Thousands of new individual points have been added to the mix, ranging from large interconnectors, that bring in power from neighbouring countries, through to wind farms, solar panels, small gas and diesel engines.

The energy mix has been changing radically, with low carbon sources expected to provide 58% of Great Britain’s power by 2020, up from 22% in 2010 and 53% in 2018. However, the security standards at which the electricity grid needs to be operated remain the same; these are predominantly voltage and frequency, and nominally 230 V and 50Hz for a domestic consumer.

The operation of the Transmission system, including maintaining these standards is overseen by the National Grid Electricity System Operator (ESO), using a set of vital tools it needs to have available, known as ancillary services. Some of this capability was inherent in large generators, which could provide the ancillary services required to keep a stable transmission system. Maintaining system stability, with thousands of generation points — a large part of which are not directly controllable — is increasingly challenging.

Click graphic to view/download

Ancillary services enable electricity to reach the end customer when and where it is required, in a safe manner, within acceptable quality standards. In addition to managing voltage and frequency levels, these standards also include maintaining adequate reserves to accommodate demand forecast uncertainties, generator breakdown and system faults. 1.

As the electricity mix changes, so must the process by which these services are secured. A diverse set of existing and genuinely new solutions will be needed to keep the lights on in the net zero carbon future.

Three steps to creating the right environment for a stable, resilient future grid:

1. Make the value of ancillary services transparent

In order for companies to help the ESO, be they generators or other service providers, it must be open and transparent about what’s needed to maintain grid stability and build resilience for the future.

“The ESO is the only buyer in the ancillary services market and is well-positioned to understand how the system is evolving. It should be proactively flagging how its needs may evolve in the future, so that the market can develop solutions to meet them”, says Marcelo Torres, Drax’s Regulation Manager – Markets.

Certain ancillary services still don’t have their own competitive markets and are provided as a “by-product” of the generation of electricity. An example is reactive power, for which there are no developed functioning regional markets yet. Generally, all power stations connected to the transmission network with a generation capacity of over 50MW are required to have the capability to provide this service, at a default price that may not reflect its real value to the system.

Another example is inertia, provided today largely through the heavy spinning turbines of thermal and pumped-storage hydro stations, which serve as stored energy that can slow down or smooth out sudden changes in network frequency.

If ancillary services were valued explicitly, market participants would have an insight into how much they are actually worth to the ESO and the grid’s stability, which would in turn incentivise new, competitive products to reach the market.

Torres points to technologies such as synchronous compensators, which are machines capable of providing ancillary services, including inertia and reactive power, without generating potentially unneeded electricity.

Services which can be provided by different power technologies

Click graphic to view/download

“These solutions will enable more renewables to connect safely to the network at a lower cost to consumers. For these solutions to come forward, ascribing the right value to ancillary services will be key. Without clear price signals, there is a risk of underinvestment in those technologies that provide the services needed, potentially resulting in price shocks for consumers”.

“The ESO is moving in the right direction with its recent Network Development Pathfinder projects. It has accelerated this work, launching its first ever tender for inertia and should roll out similar initiatives GB-wide. Such procurements should align with existing investment signals such as those provided by the Capacity Market. This should allow for the right type of capacity to be built where it is most needed, delivering a secure and resilient grid”.

2. Create market confidence

“Constructing the machinery and infrastructure that will enable the ESO to operate a carbon-free system will require major financial investment, as well as years to plan and build,” says Torres.

“This can only be achieved if Ofgem designs the ESO’s incentives in a way that rewards it for taking bold, strategic initiatives that have the potential to deliver good value for money to consumers in the long-term.”

Evidence of this working is shown in the success of offshore wind, which now provide around a sixth of Great Britain’s electricity, at record low prices. This is partly due to the government providing offshore wind developers with revenue stabilisation mechanisms, known as ‘Contracts for Difference’ (CfDs).

This is not a new concept for government and regulators around the world looking to enable investment in energy infrastructure. Financing renewables to achieve decarbonisation is enabled through CfDs or market-led hedging tools, like Power Purchase Agreements. Investment to ensure there is sufficient capacity to meet peak demand is secured through long-term contracts, competitively awarded through the Capacity Market. Similarly, investment in interconnection is supported through Ofgem’s ‘Cap & Floor’ regime.

“Subsidy isn’t required for investment in ancillary services. What’s needed,” says Torres, “is a clear and stable market framework designed around the system’s needs, which provides a mix of short and long-term signals. More certainty over the market landscape and the expected returns will lower the risk of these investments and get the solutions needed at a lower overall cost to consumers.”

“Long-term procurement is not the right answer everywhere. Where there is already a mature and liquid market, such as the case for frequency response, buying services closer to real time makes sense for two reasons. First, it allows prices to reflect more accurately the market conditions and therefore the real value of a service at the time when it is needed. Second, it allows a wider range of resources to participate in the market, increasing competition. Striking the right balance between short and long-term procurement is key to create a sustainable ancillary services market.”

Currently, the ESO requests that electricity-generation firms commit to supplying a certain amount of power for the purpose of frequency response, a month ahead of time. For resources such as wind farms or solar, which are dependent on the weather, this makes it extremely difficult for them to enter this market. Even for conventional large thermal generators it can be a problem, as many of them do not know how or if they will be running beyond a few days.

“The ESO is currently conducting some trials procuring frequency response one week in advance. While this is an improvement, it is still too long a lead time for intermittent sources or demand-side response, which ideally need day-ahead or almost real time auctions to unlock their full potential,” says Torres.

“The ancillary services market has been through a prolonged period of change since the ESO published its System Needs and Product Strategy in 2017. Without knowing how the market landscape will look like by the end of these reforms, it’s difficult for providers to develop the right solutions.”

A shift in thinking, which considers what the electricity network might require in the future, and how to provide the market with financial incentives to make it a reality, is needed. A resilient, stable future system is to the advantage of consumers.

3. Diversify

There will be no silver bullet that can solve all the challenges the energy transition poses. Maintaining system reliability in a high renewables world will require large amounts of dispatchable power, with different response time and duration. From small batteries and demand-side response that will manage instantaneously frequency fluctuations, through to large pumped storage hydro plants that will provide backup power during the days when the wind won’t blow and the sun won’t shine. A framework structured around the system’s different needs should aim at harnessing flexibility across a range of technologies and sizes.

 

Truly diversifying will also involve unlocking the flexibility potential on the distribution grid. To achieve this, the way that access to the distribution network is managed and paid for will need to evolve. Today, with big parts of the distribution network being congested, small flexible assets are asked to wait in the queue for several years or face disproportionate amount of network reinforcement costs to get connected.

Machine hall, Cruachan Power Station

The ongoing review of the network access and forward-looking charging arrangements needs to address these barriers soon, if we are serious about making use of flexibility to foster the energy transition, while keeping consumer bills as low as possible.

Since 2018, GB’s Distribution Network Operators (DNOs) have been tendering and procuring for various flexibility services to manage congestion in regional electricity grids. In 2019, they published a roadmap setting out the steps they intend to take to enable a smarter and more flexible energy system.

“As we transition from DNOs towards Distribution System Operation – a wider set of functions and services to run a smart distribution grid – the regional networks will be open to market-based flexibility solutions. DSOs will be able to compete on a level playing field, offering options for network reinforcement. As DNOs move from trials to more structured flexibility procurement, harmonisation and effective coordination with the national markets will be the key pre-requisites to reveal the true value that flexibility can bring to the energy system,” argues Torres.

“To build a modern and resilient grid we will need a wider lens on what’s possible. It’s going to be an exciting journey on the road to net zero!”

This story is part of a series on the lesser-known electricity markets within the areas of balancing services, system support services and ancillary services. Read more about black start, system inertia, frequency response, reactive power, voltage control and reserve power. View a summary at The great balancing act: what it takes to keep the power grid stable and find out what lies ahead by reading Balancing for the renewable future.

The men who built a power station inside a mountain

12 November 2019

Power generation
Cruachan tunnel tigers

Travelling through the Highlands towards the West Coast of Scotland, you pass the mighty Ben Cruachan – its 1,126 metre peak towers over the winding Loch Awe beneath. It is the natural world on a huge scale, but within its granite core sits a manmade engineering wonder: Cruachan Power Station.

Opened by The Queen in 1965, it is one of only four pumped-hydro stations in the UK and today remains just as impressive an engineering feat as when it was first opened.

Cruachan is operated safely and hasn’t had a lost time injury in 15 years. The robust health and safety policies and practices employed at the power station were not in place all those decades ago.

It took six years to construct, enlisting a 4,000-strong workforce who drilled, blasted and cleared the rocks from the inside of the mountain, eventually removing some 220,000 cubic metres of rubble. The work was physically exhausting – the environment dark and dangerous.

Nicknamed the ‘Tunnel Tigers’, the men that carried the work out came from far and wide, attracted to its ambition as well as a generous pay packet reflective of the danger and difficulty of the work. But few of them were fully prepared for the extent of the challenge.

One labourer, who started at Cruachan just after his 18th birthday, recalls: “I was in for a shock when I went down there. The heat, the smoke – you couldn’t see your hands in front of you.”

Inside the mountain

The work of hollowing out Ben Cruachan was realised by hand-drilling two-to-three metre deep holes into the granite rockface. An explosive known as gelignite, which can be moulded by hand, was packed into the drilled holes and detonated. The blasted rocks were removed by bulldozers, trucks and shovels, before drilling began on the fresh section of exposed granite. In total, 20km of tunnels and chambers were excavated this way, including the kilometre-long entrance tunnel and the 91-metre-long, 36-metre-high machine hall.

Wilson Scott was just 18 when he got a job working as a labourer at Cruachan while the machine hall was being cleared out.

“The gelignite, it had a smell. Right away I was told not to put it near your face,” he says, “It’ll give you a splitting headache and your eyes will close with the fumes that come off it. It was scary stuff.”

This process allowed for rapid expansion through the mountain. With three or four blasts each 12-hour shift, some 20 metres of rock could be cleared in the course of a day. Activity was constant, and to save the men having to make the journey back up to the surface, refreshments came to them.

“There was a bus that went down the tunnel at 11 o’clock with a huge urn of terrible tea,” says Scott. “Most of the windows were out of the bus because the pressure of the blasting had blown them in.”

The tea did little to make the environment hospitable, however. From the water dripping through the porous rocks making floors slippery and exposed electrics vulnerable, to the massive machinery rushing through the dense dust and smoke, danger was ever-present. Loose rocks as large as cars would often fall from exposed walls and ceilings while the regular blasting gave the impression the entire mountain was shaking.

“I’ll tell you something: going into that tunnel the first time,” Scott says. “It was a fascinating place, but quite a scary place too.

Above them, on top of the mountain, a similarly intrepid team tackled a different challenge: building the 316-metre-long dam. They may have escaped the hot and humid conditions at the centre of Cruachan, but their task was no less daunting.

Cruachan dam construction, early 1960s

Cruachan dam construction, early 1960s

On top of the dam

Out in the open, 400 metres above Loch Awe, the team were exposed to the harsh Scottish elements. John William Ross came to Cruachan at the age of 35 to work as a driver and spent time working in the open air of the dam. “You’d get oil skins and welly boots, and that was it. We didn’t have gloves, if your hands froze – well that’s tough luck isn’t it.” Mr Ross sadly passed away recently.

Charlie Campbell, a 19-year-old shutter joiner who worked on the dam found an innovative way around the cold. “You’d put on your socks, and then you’d get women’s tights and you’d put them over the top of the socks, and then you’d put your wellies on and that’d keep your feet a wee bit warmer. We thought it did anyway. Maybe it was just the thought of the women’s stockings.”

Pouring the concrete of the dam – almost 50 metres high at its tallest point – was precarious work, especially given the challenges of working with materials like concrete and bentonite (a slurry-like liquid used in construction).

“It was horrible stuff. It was like diarrhoea, that’s the only way of explaining it,” says Campbell. “There was a boy – Toastie – I can’t remember his real name. He fell into it. They had quite a job getting him out, they thought he was drowned, but he was alright.”

Many others were not alright. The danger of the work and conditions both inside and on top of the mountain meant there was a significant human cost for the project. During construction, 15 people tragically lost their lives.

Today a carved wooden mural hangs on the wall of the machine hall to capture and commemorate the myth of the mountain and the men who sadly died – a constant reminder of the bravery and sacrifice they made.

The men that made the mountain

The Cruachan ‘Tunnel Tigers’

The Tunnel Tigers were united in their efforts, but came from a range of backgrounds and cultures. Polish and Irish labourers worked alongside Scots, as well as displaced Europeans, prisoners of the second world war and even workers from as far as Asia. The men would work 12, sometimes 18-hour shifts, seven days a week. Campbell adds that some men opted to continue earning rather than rest by doing a ‘ghoster’, which saw them working a solid 36 hours.

Many men would make treble the salary of their previous jobs, with some receiving as much as £100 a week, at a time when the average pay in Scotland was £12. Some teams’ payslips were stamped with the words ‘danger money’ – illustrative of the men’s motivation to endure such life-threatening work.

While it was a dangerous and demanding job, many of the Tigers look back with fond memories of their time on the site and many stayed in the area for years after. “It was an experience I’m glad I had,” says Scott. “It puts you in good stead for the rest of your days.”

As for Cruachan Power Station, its four turbines are still relied on today by Great Britain to balance everyday energy supply. As the electricity system continues to change, the pumped hydro station’s dual ability to deliver 440 megawatts (MW) of electricity in just 30 seconds, or absorb excess power from the grid by pumping water from Loch Awe to its upper reservoir, is even more important than when it opened.

Standing at the foot of a mountain more than 50 years ago, the men about to build a power station inside a lump of granite may have found it unlikely their work would endure into the next millennium. They may have found it unlikely it was possible to build it at all. But they did and today it remains an engineering marvel, a testament to the effort and expertise of all those who made it.

Visit Cruachan – The Hollow Mountain

Further statement in relation to the AGM vote on political donations

15 October 2019

Investors
Meeting Seminar Conference Business Collaboration Team Concept

In the lead up to the 2019 AGM, the Company undertook initial consultation with major shareholders and received a variety of feedback on both the Resolution and the Company’s approach to engagement with regulators and policymakers including political parties and governments.

Following the AGM, the Board of Directors initiated further engagement to facilitate a clear understanding of the reasons underpinning the votes cast against the Resolution. This included writing to the Company’s largest shareholders and offering to discuss how the Company proposed to respond to points raised during the initial consultation and policy on stakeholder engagement. The Company is grateful to those shareholders that provided feedback at that time.

The Company regularly engages with regulators and policymakers in the UK, Europe and USA (including those associated with political parties and governments) to understand and contribute to discussions on a wide range of matters which are associated with our business and delivering increased value to our shareholders. This approach is detailed on pages 32 and 33 of the 2018 Annual Report as a fundamental aspect of our stakeholder engagement. Political and regulatory risk has been identified by the Board as one of the nine principal risks that the business faces. Activities of this nature are not designed to support any political party or to influence public support for a particular party and would not be thought of as political donations in the ordinary sense of those words.

Reflecting the feedback received from shareholders, it has been determined that within future Annual Reports additional disclosure will be provided. This will describe the forms of engagement that have taken place with regulators and policymakers in the financial year as well as additional disclosure regarding the oversight of that engagement. To assure shareholders of the governance associated with managing engagement and transparency, the Company has also developed and published a policy explaining how stakeholder engagement is undertaken, including oversight and associated reporting.

The term ‘political donation’ is widely defined in the Companies Act 2006 (“the Act”). For clarity, the Company has not made, and does not intend to knowingly make, political donations. The Company continues to believe it is in the best interests of the business and shareholders to renew the authority most recently granted at the 2019 AGM to avoid any inadvertent infringement of the Act.

Prior to 2019, the Company had proposed an authority to spend up to £50,000 under each of the three categories covered by the Act. At the 2019 AGM, Drax sought an authority to spend up to £100,000 under the same three categories which was approved by a majority of shareholders.Nonetheless and reflecting feedback received in connection with the Resolution, at the 2020 and future AGMs the Company will propose an authority to spend up to £100,000 in each of the three categories but will introduce an aggregate cap of £125,000.

Further explanation on these matters, and our ongoing engagement with shareholders, will be included in the 2019 Annual Report and notice of the 2020 AGM.

Enquiries:

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

Media:

Drax External Communications: Matt Willey
+44 (0) 1757 612 285

Smart ways to charge EVs

Electrification
Electric car

The future of electric cars and electric vans holds great potential – not just for the transport industry’s overall carbon footprint, but for the populations of heavily congested, polluted cities and even individual drivers looking for more efficient fuel costs.

That future is approaching fast. By 2040 or even as soon as 2035 no new cars or vans sold in the UK can be solely powered by diesel or petrol. While this is a positive step, it brings with it a shift in the way drivers will need to manage the way they plan journeys and, more importantly, refuel.

Dark Blue Electric Sports Car Driving

For years drivers have relied on a quick and plentiful supply of fuel at petrol stations. But an EV doesn’t charge as quickly as a conventional car, nor are fast charging points widespread – at least not right now.

The change will be considerable, but it won’t necessarily take shape in a single form. Here we look at four things that will become increasingly influential in how drivers recharge their EVs over the coming years.

  1. Smart charging and time-of-use tariffs

Electricity costs more to produce and supply at certain times of the day. This wholesale price depends on the demand for power, weather conditions and the costs of different generation technologies and fuels.

For example, electricity is often more expensive in the evenings when people are coming home from work and turning on lights, TVs, ovens and plugging in devices. Just a few hours later it rapidly drops in price as homes and offices turn off lights and appliances. But the power system is changing.

The price of electricity is increasingly driven by less predictable factors such as the weather. On windy and sunny days, wind and solar generation can drive down the cost of producing power. On calm and cloudy days, the costs of electricity can increase.

While this, in theory, makes it sensible to wait for a cheap period of time to plug in and charge an electric vehicle (EV), in practice people are unlikely to spend the time sit refreshing websites which display the price of electricity in real time to get the best value. Instead, the use of ‘smart charging technology’ can play a big role to capitalise on fluctuations in prices. Electric charge in a village house. Outside the city the countryside.

Smart charging technology will be able to monitor things like electricity prices and even electricity usage across an entire site (for example across a business where many devices are using electricity) and automate the charging process to make use of the best prices and limit overall electricity use.

Rather than needing someone to recharge EVs at one o’clock in the morning, this means people or businesses can plug in at times convenient to them and set their vehicles to charge at the cheapest times and have an appropriate amount of charge to carry out tasks when they need to.

“By shifting power usage into cheaper periods you’re saving money and you can be more sympathetic to supply and demand limits on a company,” explains Adam Hall, who leads Drax’s EV proposition. “If I know my battery will be fully charged by nine in the morning, do I care if it charges immediately or delays it and saves me a few pounds?” For business fleet owners who manage large numbers of electric vehicles the difference this can make is even larger, he adds.

  1. Vehicle-to-grid (V2G) technology

Each EV has a battery in it that powers the vehicle’s motor. But what if the electricity stored in that battery could also be harnessed to deliver electricity back to grid? And what if that concept could be used to collect a small portion of power from every idle EV in the country and use it to plug gaps in the electricity system?

“There are over 30 million cars on UK roads. National Grid predicts by 2050, 99% of those vehicles will be powered by electricity,” explains Hall. “The majority of cars remain idle for 95% of any day. That’s a huge amount of storage potential that could be used to balance the grid at key times. It’s a battery network that assets around the country will be able to use.”

This concept is what’s called vehicle to grid technology  (V2G), and while it holds great potential, it’s still some way from becoming a mainstream source of reserve power. Right now the technology is costly and limited – only ‘CHAdeMO’ charging systems, as found on Japanese models, actually support bi-directional charging. Nevertheless, Hall remains optimistic of its future role in the energy system, particularly as this technology will be hugely important in managing future grid constraints

“The cost of bi-directional hardware is coming down all the time,” he says. “At the moment there aren’t enough vehicles, we don’t have the scale to do it, but I fully believe it will change quite dramatically.”

For domestic users the benefit will be less immediate than it will be for entire countries. For business fleet managers, allowing the grid to take some power from their idle vehicles could lead to financial compensation or other advantages for offering grid support.

  1. The out of sight, out of mind approach: third party management schemes

More suited for businesses managing whole fleets of vehicles, employing a third party to manage the charging of vehicles allows for the delegation of a potentially costly and time-consuming task.

Adam Hall, Drax EV proposition lead, with Drax’s electric vehicle fleet service.

“Effectively the customer knows they’ll get the vehicles with the amount of charge they want when they need it,” says Hall. “That might be for the cheapest price or as fast as possible. It means the customer doesn’t have to think, they just get their charged vehicle in the optimum way for their needs.”

Third party providers could also open up new charging businesses models, such as flat monthly rates for unlimited vehicle charging or all-renewable services. By taking the technical aspects of running a fleet out of businesses hands, third parties could even serve to lower the barrier to EV adoption.

  1. Mandatory managed charging

It’s difficult to accurately know how much demand electric vehicles will place on the electricity system– some estimates see demand growing in Great Britain as much as 22% by 2050 as a result of EVs.

While the constant development of battery and charging technology will likely mean this prediction will come down, there are some theories as to how the country will need to deal with this rapid growth. One of these is to actually turn down the electricity surging through charging points at certain points to prevent widespread blackouts.

“The idea is there to protect the grid,” explains Hall. “When local distribution networks have a lot of demand they may need to turn charge points down.” He adds there will likely be exemptions for emergency services, however.

Hall is sceptical mandatory managed charging would ever really come into play, for the damage it would do to consumer attitudes to EVs. The idea also taps into wider scaremongering around EVs and quite how much they will push up electricity demand.

Instead what will really need to shift for a future of efficiently charged vehicles is a mindset shift. “There’s a psychological element to it,” he suggests. “Everyone goes through some range anxiety at first but soon realises the technology is sound.”

As battery technology continues to improve, vehicles evolve to go further on a single charge, and networks of super-fast charge points expand, transitioning to electric vehicles will become easier and more economical for businesses than continuing to depend on fossil fuel.

“I personally believe once electric vehicles are doing 300 miles on a single charge, the requirement for on-route charging will be pretty low,” says Hall. “Not many people drive 300 miles, need to recharge at a service station and then drive anther 300 in one fell swoop. It’s much more important to have good charging installations at work and at home.”

There are many ways in which EVs will change the way the world drives, from how we charge them to how and where we travel. We can be certain this will mean a shift in mindsets and our approach to transport. What remains uncertain is just how quickly and widespread that shift will be.

From coal to pumped hydro storage in 83 mountainous miles

7 October 2019

Power generation
Moving of transformers from Longanett to Cruachan

Nestled in in the Western Highlands in Scotland, Cruachan Power Station is surrounded by a breathtaking landscape of plunging mountainsides and curving lochs, between which weave narrow roads.

It makes for scenic driving. What might be trickier, however, is transporting 230 tonnes of electrical equipment up and down said mountains, navigating narrow bends.

But that’s exactly what a team from Drax was tasked with when it came to moving two 115 tonne transformers, the equipment used to boost electricity’s voltage. They were in storage 83 miles away at Longannet, currently being demolished, near Fife.

“You’re moving a piece of equipment that is designed to stay in one place. It’s not designed to go on the roads,” explains Jamie Beardsall, an Electrical Engineer from the EC&I Engineering team who worked on the project. “You’re very aware of your environment and the risks. Everything is checked and doubled checked.”

Transformers being driven to Drax’s Cruachan pumped storage hydro power station

The complicated task required colleagues from both Cruachan and Drax power stations to collaborate from the very beginning. Gary Brown, Mark Rowbottom and Jamie from the EC&I Engineering team based in Yorkshire teamed up with Gordon Pirie and Roddy Davies from Scotland who met frequently and planned the project alongside specialist transport contractor, ALE, which advised on heavy lifting and movement.

Planning and execution of the works also required constant liaison and coordination with the police and highway authorities in both Scotland and England. But more than that, the transformers’ one-by-one journey from the demolition site of what was once Europe’s biggest coal-fired power station, to a hydro-powered energy storage site on the other side of Scotland, represents the continual shift of Great Britain’s electricity away from fossil fuels.

Stepping up voltage

Transformers are an essential part of the electricity system. By increasing or decreasing the voltage of an electrical current they can enable it to traverse the national grid or make electricity safe to enter our homes.

“When we generate electricity, it is at a lower voltage than we need to send it out to the national grid,” says Beardsall. “We use transformers to increase the voltage so it can go out to the national grid and be transmitted over long distances more efficiently. We then reduce the voltage again so it can be brought safely into our homes.”

While all transformers apply the same principles for stepping voltage up and down, the two transformers that were transported through the Highlands to Cruachan were designed specifically for the pumped storage hydro power station, but stored at Longannet where there was more space. At the time, both stations where owned by Scottish Power. Cruachan was purchased by Drax on the last day of 2018.

Engineers at Cruachan Power Station in front of one of the original transformers

When transported, each transformer weighs 115 tonnes and is almost four metres high. Transporting them isn’t as simple as loading them into the back of a van.

“You can’t transport them in a fully built state, they would be too heavy and wouldn’t go under bridges,” says Beardsall. “We had to strip them back to the core and now we’re working to reassemble them on site.”

Cutting down to the core

Each transformer consists of two main components; a core made of iron, and two windings made of copper. The transformer itself has no moving parts. When a voltage is applied to one of the transformer windings (the primary winding), a magnetic field is created in the iron core. This field then induces a voltage into the other winding (the secondary winding). Depending on the number of coils on each set of windings, the output voltage will increase or decrease. More coils on the secondary winding steps the voltage up, fewer coils on the secondary steps the voltage down.

This entire apparatus is submerged in an oil to provide insulation and keep the transformer cool, meaning the first step was to drain 50,000 litres of oil from each transformer. This was then sent to a refinery to be processed, cleaned and stored until the transformers are reassembled at Cruachan.

Oil removed, the Drax engineers oversaw and managed the dismantling of the transformers at Longannet. Once the transformers were stripped down to a state suitable for movement, they were loaded up one-by-one for transportation.

Meanwhile, at Cruachan, engineers worked on construction of a purpose built bunded area for storage of the transformers. The transformers were destined to be stored on land outside the main admin buildings, adjacent to Loch Awe.

Loch Awe at Cruachan Power Station

The Loch itself is a beautiful place with abundant animal and birdlife – and a fish farm is located almost directly opposite the power station. In the event of a transformer leaking, the natural environment must be protected. An oil-tight storage area was therefore built, to ensure that no oil would end up in the Loch.

The road to Cruachan

Rather than heaving each of the transformers onto a trailer, each one was raised using hydraulic jacking equipment. A trailer was then driven underneath, and the transformer lowered onto it.

“The trailer is specifically designed to take the transformers and fit certain dimensions,” explains Beardsall. “It has 96 wheels over 12 sets of axles, each of which can be turned individually to assist in navigating around tight spots.”

The trailers are towed by large tractor units, each weighing over 40 tonnes. These provided the motive power to move the transformers. Each was moved in two stages over the space of two weeks. The first transformer over the course of a weekend, the second in the middle of the night some 10 days later.

“When we could go was governed by the police and highways agencies as they need to close the roads,” says Beardsall. “We set off from Longannet at 7pm on the Friday evening and moved them 60 miles along the route to a layby where we stored them. That leg took approximately five hours. Then the second leg was the last 25 miles to Cruachan, carried out on the Sunday morning of the same weekend.”

Navigating the Highlands with 115 tonnes of hugely valuable equipment is where the real challenge came in. Hills, dips and tight turns made for slow progress.

Generator transformer at Cruachan Power Station

The original generator transformer at Cruachan Power Station

“The average speed was about 10mph, but we’re going through the Highlands so it was quite a bit slower than that in some places. We occasionally hit 20+ mph at points, but that was definitely for the minority of the time!” says Beardsall. “Some of the roads were so narrow it was difficult to get two cars past each other. The contractors also had to put metal plating over bridges because they weren’t strong enough to take the load.”

Having safely arrived at Cruachan, the transformers are being stored at surface level until they are needed, at which time they will be taken down the half-a-mile-long tunnel into the energy storage station.

“Typically a transformer has a design life of 25 years, although they can last longer” explains Beardsall. “There are four units at Cruachan and the transformers for two of these units have already been replaced, so these transformers would be used to replace the existing transformer for the two remaining units should it ever be needed. The existing transformer having been in operation since 1965.”

Moving heavy objects is part and parcel of running Drax’s multiple power stations around the country. However, navigating the Highlands, the very terrain which makes Cruachan possible, added a unique challenge for Drax’s engineers.

Visit Cruachan Power Station – The Hollow Mountain

Read the press release

A brief history of Scottish hydropower

1 October 2019

Power generation
The Clatteringshaws Dam in the Galloway Forest Park in south west Scotland. Built by Sir Alexander Gibb & Partners in 1932-38, it is on the south west

Over the last century, Scottish hydro power has played a major part in the country’s energy make up. While today it might trail behind wind, solar and biomass as a source of renewable electricity in Great Britain, it played a vital role in connecting vast swathes of rural Scotland to the power grid – some of which had no electricity as late as the 1960s. And all by making use of two plentiful Scottish resources: water and mountains.

But the road to hydro adoption has been varied and difficult, travelled on by brave death-defying construction workers, ingenious engineers and the inspirational leadership of a Scottish politician.

To trace where the history of Scottish hydropower began, we need to go back to the end of the 19th Century and to the banks of Loch Ness.

Loch Ness, Scottish Highlands

Loch Ness, Scottish Highlands

From abbeys to aluminium 

It was on the shores of Loch Ness that one of the first known hydro-electric schemes was built at the Fort Augustus Benedictine abbey. The scheme provided power to the monks living there as well as 800 village residents – though legend has it that their lights went dim every time the monks played their organ.

However, it was the British Aluminium Company, formed in 1894, that first realised the huge potential of Scotland’s steep mountains, lochs and reliably heavy rainfall to generate substantial amounts of hydro power. In need of a reliable source of electricity to help turn raw bauxite into aluminium, the firm established a hydro-electric plant and smelting works at Foyers and Loch Ness. Several similar schemes to support the aluminium industry soon appeared around the country.

But it took another 20 years for the first major hydro-power project to supply electricity to the public to emerge.

In 1926, the Clyde Valley Electrical Power Co. opened the Lanark Hydro Electric Scheme, which used energy from the River Clyde’s flow to create power. Now owned by Drax, it still has a generation capacity of 17 MW – enough to supply more than 15,000 homes.

River Clyde, Lanark

It was quickly followed by power stations at Rannoch and Tummel in the Grampian mountains and, in 1935, by what became a highly influential scheme in the history of Scottish hydro power at Galloway.

Drawing enough energy from local rivers to support five generating power stations, the project was the largest run-of-the-river scheme ever created. Architecturally, it also set the tone for later projects with stylised dams and modernist turbine halls.

A fairer share of power for the Highlands

The Galloway scheme supplied energy to a wide area, too, including parts of the central Highlands. Scottish Labour MP Tom Johnston, a staunch socialist and Scottish patriot saw how this new power source could provide massive benefits to northern communities. In the early 1940s, only an estimated one in six Scottish farms and one in a hundred small land crofts had electricity.

In 1941, Johnston became Scotland’s Minister for State with a vision, as he put it, to create “large-scale reforms that might mean Scotia Resurgent”. Expanding hydro power was a priority.

Tom Johnston MP

Two years later, he formed the North of Scotland Hydro-Electric Board (NSHEB). Its aim was to create several new schemes, including at Tummel and Loch Sloy, that would supply the national grid and bring electricity to more rural Scottish areas.

The projects were met with fierce opposition from landowners and local pressure groups who feared new dams and power stations would ruin the countryside and bring unwelcome industrialisation.

Public enquiries followed, but the board’s promises that the developments would be sensitive to the environment and bring cheap electricity in areas such as the Isle of Skye and Loch Ewe eventually won the day.

Thousands of local men, as well as German and Italian former prisoners of war, were drafted in to work on the projects.

Among the most courageous were workers known as ’Tunnel Tigers’ who blasted away rock using handheld drills and gelignite to create water channels and underground chambers, including at Drax’s Cruachan pumped storage hydro station.

Deaths caused by everything from blast injuries to fires were common. The men also had to cope with incessant rain and cold, and were housed in bleak military-style camps. With little to do in their spare time, besides drink, fights would break out regularly.

But the financial rewards were enormous, with wages up to ten times higher than labourers employed on Highland estates could expect.

Glenlee penstocks

The future takes shape

The board’s first small projects were completed in 1948 at Morar and Nostie Bridge, supplying electricity to areas including parts of Wester Ross. Catherine Mackenzie, a local widow, performed the Morar opening ceremony, reportedly declaring: “Let light and power come to the crofts.”

Bigger schemes were plagued by problems. Conveyor belts had to be built to transport stone across 1.75 miles of moor during construction at Sloy, for instance, and there were frequent stone and timber shortages.

But Sloy eventually opened in 1950, the largest conventional hydro electrical power station in Great Britain with an installed capacity of 128 MW. It would be followed by major schemes at Glen Affric and Loch Shin.

By the mid Sixties, the Board had built 54 main power stations and 78 dams. Northern Scotland was now 90% connected to the national grid. Hydro Board shops began popping up on high streets, selling appliances and collecting bill payments.

Tom Johnston died in 1965, aged 83. The Provost of Inverness declared: “No words can say how grateful we are.”

Cruachan Power Station

Loch Awe beside Cruachan Power Station

That same year, the world’s then largest reversible pumped storage power station opened at Cruachan. During times of low electricity demand, its turbines pump water from Loch Awe to the reservoir above. When demand rises, the turbines reverse, and water flows down to generate power. A similar scheme opened at Foyes in 1974.

Glendoe, near Loch Ness, was the most-recent major hydro scheme to be built. Opening in 2009, it has a generation capacity of 100 MW.

There are plans for a pumped storage scheme at Coire Glas, with a storage capacity of 30 GWh– more than doubling Great Britain’s current total pumped storage capacity. Drax’s Cruachan Power Station could also be expanded.

In recent years, however, the real growth has been in smaller hydro-electric schemes that may power just one or a handful of properties – with more than 100 MW of such generation capacity installed in the Highlands since 2006.

Boosting the environment and economy

Scotland now provides 85% of Great Britain’s hydro-electric resource, with a total generation capacity of 1,500 MW. Improved power supplies have attracted more industry to the Highlands, without seriously altering its character. And access roads created during hydro-power schemes’ construction have opened up remote areas to tourism.

For many, the dams built by NSHEB are among the greatest construction achievements in post-war Europe and remain an essential part of Great Britain’s attempts to move towards a low-carbon energy future.

How will 5G revolutionise the world of energy and communications?

30 August 2019

Electrification
Smart cellular network antenna base station on the telecommunication mast on the roof of a building.

What should be made of the 5G gap? It’s the difference between what some commentators are expecting to happen thanks to this new technology and what others perhaps more realistically believe is possible in the near future.

What we call 5G is the fifth generation of mobile communications, (following 4G, 3G, etc.). It promises vastly increased data download and upload speeds, much improved coverage, along with better connectivity. This will bring with it lower latency – potentially as low as one millisecond, a 90 per cent reduction on the equivalent time for 4G – and great news for traders and gamers, along with lower unit costs.

Trading desk at Haven Power, Ipswich

The latest estimates predict that 5G will have an economic impact of $12 trillion by 2035 as mobile technology changes away from connecting people to other people and information, and towards connecting us to everything.

Some experts believe the effects of 5G will be enormous and almost instantaneous, transforming the way we live. It will have a huge effect on the internet of things, for instance, making it possible for us to live in a more instant, much more connected world with more interactions with ‘smart objects’ every day. Driverless cars that ‘talk’ to the road and virtual and augmented reality to help us as we go could become part of our everyday lives.

Others see 5G as a revolution that will begin almost immediately, but which could take many years to materialise. The principal reason for this is the sheer level of investment required.

The frequencies being used to carry the signal from the proposed 5G devices can provide an enormous amount of bandwidth, and carry unimaginable amounts of data at incredible speeds. But they cannot carry it very far. And the volume of devices connected to this network will be enormous. The BBC estimates that between 50 and 100 billion devices will be connected to the internet by 2020 – more than 12 for every single person on Earth.

So in order to support the huge increase in connectivity that is anticipated a reality, there will be a need for a comparably large increase in the number of base stations – with as many as 500,000 more estimated to be needed in the UK alone. That’s around three times as many base stations as required for 4G.

To carry the amount of data anticipated without catastrophic losses in signal quality will require the stations to be no more than 500m apart. While that may be technically possible in cities, it will only happen as a result of huge amounts of investment. And what will happen in the countryside, with its lower population density? It seems doubtful in the extreme that any corporation will regard it as a potentially profitable business decision to build a network of base stations half a kilometre apart in areas where few of their customers live. And that’s without taking into account the town and country planning system or the views of residents, who may not welcome new base stations near their homes.

Until this year, the only two workable examples of functional 5G networks are one built by Samsung in Seoul, South Korea, and another by Huawei in Moscow in advance of the 2020 Football World Cup. Although the first UK mobile networks have now begun to offer the new communications standard, 5G is still clearly a long way from being able to deliver on its potential.

What will 5G mean for the world of energy?

A report from Accenture contains a number of predictions about how 5G may change the energy world by helping to increase energy efficiency overall and accelerating the development of the Smart Grid.

  1. 5G uses less power than previous generations of wireless technology

This means that less energy will be used for each individual connection, which will take less time to complete than with 4G devices, thereby saving energy and ultimately money too. It is important to remember that even though such savings will be significant, they will need to be offset against the huge global increase in communications through 5G-connected devices.

  1. Accelerating the Smart Grid to improve forecasting

5G has the potential to help us manage energy generation and transmission more efficiently, and therefore more cost-effectively.

The report’s authors anticipate that “By allowing many unconnected energy-consuming devices to be integrated into the grid through low-cost 5G connections, 5G enables these devices to be more accurately monitored to support better forecasting of energy needs.

  1. Improve demand side management and reduce costs

 “By connecting these energy-consuming devices using a smart grid, demand-side management will be further enhanced to support load balancing, helping reduce electricity peaks and ultimately energy costs.”

  1. Manage energy infrastructure more efficiently and reduce downtime

By sharing data about energy use through 5G connections, the new technology can help ensure that spending on energy infrastructure is managed more efficiently, based on data, in order to reduce the amount of downtime.

And in the event of any failure, smart grid technology connected by 5G will be able to provide an instant diagnosis – right to the level of which pylon or transmitter is the cause of an outage – making it easier to remedy the situation and get the grid up and running again.

5G could even help turn street lighting off at times when there are no pedestrians or vehicles in the area, again reducing energy use, carbon emissions, and costs. Accenture estimate that in the US alone, this technology has the potential to save as much as $1 billion every year.

More data, more power

Although 5G devices themselves may demand less power than the telecoms technology it they will eventually replace, that doesn’t tell the whole story.

More connected devices with more data flowing between them relies on more data centres. This has led some data centres to sign Power Purchase Agreements to both reduce the cost of their insatiable desire for electricity and also ensure its provenance.

Data centre

As well as data centres, the more numerous base stations needed for 5G will consume a lot of power. One global mobile network provider says just to operate its existing base stations leads to a £650m electricity bill annually, accounting for 65% of its overall power consumption.

Base station tower

Contrary to the findings of the Accenture report, a recent estimate has put the power requirement of an individual 5G base station at three times that of a 4G. Keeping in mind that three of these are needed for every existing base station, the analysis by Zhengmao Li of China Mobile, suggests a nine-fold increase in electricity consumption just for that key part of a 5G network.

With the Great Britain power system decarbonising at a rapid pace, the additional power required to electrify the economy with new technologies shouldn’t have a negative environmental impact – at least when it comes to energy generation.

However, as we use ever-more powerful and numerous devices, we need to ensure our power system has the flexibility to deliver electricity whatever the weather conditions. This means a smarter grid with more backup power in the form of spinning turbines and storage.

In energy storage timing is everything

21 August 2019

Power generation
Cruachan Power Station

Electricity is unlike any other resource. The amount being generated must exactly match demand for it, around the clock.

Managing this delicate balancing act is the job of the National Grid Electricity System Operator (ESO), which works constantly to ensure supply meets demand and the grid remains balanced. One of the ways it does this is by storing energy when there is too much and deploying it when there is too little.

Although there are many different ways of storing energy at a small scale, at grid level it becomes more difficult. One of the few ways it is currently possible is through pumped hydro storage. Cruachan Power Station in the Highlands of Scotland is one of four pumped storage facilities in Great Britain. It uses electrically-driven turbines to pump water up a mountain into a reservoir when there is excess electricity on the grid, and then releases the water stored in the reservoir back down, to spin the same turbines to generate power when it’s needed quickly.

The dual capabilities of these turbines are unique to pumped hydro storage and contribute to the overall grid’s stability. However, what dictates when Cruachan’s turbines switch from pump to generate and vice versa is all a matter of what the grid needs – and when.

The switch from pump to generate

While the machine hall of Cruachan Power Station is an awe-inspiring place for its size and location 396 metres beneath Ben Cruachan, it generates electricity much like any other hydropower station: harnessing the flow of water to rotate any number of its four 100+ megawatt (MW) turbines.

This mode – simply called ‘generate mode’ – is usually employed during periods of peak power demand such as mornings and evenings, during a major national televised event, or when wind and solar energy output drops below forecast. As a result, starting up and generating millions of watts of electricity has to be fast.

“It takes just two minutes for a turbine to run up from rest to generate mode,” says Martin McGhie, Operations and Maintenance Manager at the power station. “It takes slightly longer for the turbines to run down from generate to rest, but whatever function the turbines are performing, they can reach it within a matter of minutes.”

The reverse of generate mode is pump mode, which changes the direction of travel for the water, this time using electricity from the grid to pump water from the vast Loch Awe at the foot of Ben Cruachan to the upper reservoir, where it waits ready to be released.

In contrast to generate mode, pump mode typically comes into play at times when demand is low and there is too much power on the system, such as during nights or at weekends, when there is excessive wind generation. However, the grid has evolved since Cruachan first began generating in 1965 and this has changed when it and how it operates.

“In the early days, Cruachan was used in a rather predictable way: pumping overnight to absorb excess generation from coal and nuclear plants and generating during daytime peak periods,” says Martin. “The move to more renewable energy sources, like wind, mean overall power generation is more unpredictable.”

He continues: “There has also been a move from Cruachan being primarily an energy storage plant to one which can also offer a range of ancillary services to the grid system operator.”

The benefits of Spin mode

In between pumping water and generating power, Cruachan’s turbines can also spin in air while connected to the grid, neither pumping not generating. This is essentially a ‘standby mode’ where the turbines are ready to either quickly switch into generation or pumping at a moment’s notice (they spin one way for ‘spin pump’; the other for ‘spin generate’). These spin modes are requested by the ESO to ensure reserve energy is available to respond rapidly to changes on the grid system.

In spin generate mode, the generator is connected up to the grid but the water is ejected from the space around the turbine by injecting compressed air. The turbine does not generate power but is kept spinning, allowing it to quickly start up again. As soon as the grid has an urgent need for power, the air is released and the water from the upper reservoir flows into the turbine to begin generation in under 30 seconds.

Spin pump works on the same basis as spin generate, but with the turbine rotating in the opposite direction, ready to pump at short notice. This allows Cruachan to absorb excess generation and balance the system as soon as the ESO needs it.

“The use of spin mode by the ESO is highly variable and dependant on a number of factors e.g. weather conditions or the state of the grid system at the time” says Martin. This unpredictability of the increasingly intermittent electricity system makes the flexibility of Cruachan’s multiple turbines all the more important.

Ready for the future grid

It’s not only the types of electricity generation around the system that are changing how Cruachan operates. Martin suggests that the way energy traders and the ESO use Cruachan will continue to evolve as the market requirements and opportunities change.

Technology is also changing the market and Martin predicts this could affect what Cruachan does. “In the future we will face competition from alternative storage technologies, such as batteries, electric vehicles, as well as competition for the other ancillary services we offer.”

However, Cruachan’s flexibility to generate, absorb or spin in readiness means it is prepared to adjust to any future changes.

“Cruachan is always ready to modify or upgrade to meet requirements, as we have done in the past,” says Martin. “The priority is always to be able to deliver the services required by the grid system operator – in characteristic quick time.”

Visit Cruachan — The Hollow Mountain to take the power station tour.

Read our series on the lesser-known electricity markets within the areas of balancing services, system support services and ancillary services. Read more about black start, system inertia, frequency response, reactive power and reserve power. View a summary at The great balancing act: what it takes to keep the power grid stable and find out what lies ahead by reading Balancing for the renewable future.

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

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.