Tag: engineering

The myths, legends and reality of Cruachan Power Station’s mural

Down the kilometre-long tunnel that burrows into the dark rock of Ben Cruachan, above the giant rumbling turbines, sits something unusual for a power station: a work of art.

The wood and gold-leaf mural might seem at odds with the yellow metal turbines, granite cavern walls, and noise and heat around it, but it’s closely connected to the power station and its ties to the surrounding landscape.

The entrance tunnel might take engineers and machines to the heart of Ben Cruachan, but the mural transports viewers to the mountain’s mythical past. It tells the story of how this remarkable engineering achievement came to help power the country.

The narrative of the mural

Much like the machines and physical environment surrounding it, the Cruachan mural is big, measuring 14.6 metres long by 3.6 metres tall. Combining wood, plastic and gold leaf, the relief is interspersed with Celtic crosses, textures evocative of granite rock and gold orbs that resemble the urban lights Cruachan helps to power. Running from left to right, it tells a linear narrative that spans the history of the mountain.

An artist’s impression of the mural in the Visitor Centre at Cruachan

In the first of the mural’s three segments is a Scottish red deer, a native species that still thrives in Scotland today. Below it is the figure of the Cailleach Bheur, a legendary old woman or hag found across Gaelic mythology in Scotland, Ireland and on the Isle of Man. The Cailleach has a symbolic representation of a variety of roles in different folklores, but she commonly appears as a personification of winter, and with that, as a source of destruction.

In the context of Ben Cruachan, Cailleach Bheur is often taken to mean the ‘Old Hag of The Ridges,’ a figure who acts as the mythical guardian of a spring on the mountain’s peak. The mural tells her story, of how she was tasked to cover the well with a slab of stone at sundown and lift it away at sunrise. One evening, however, she fell asleep and failed to cover the well, allowing it to overflow and cause water to cascade down the mountain, flooding the valley below and drowning the people and their cattle.

The mural within the Turbine Hall at Cruachan Power Station undergoing maintenance  [November 2018]

This serves as the legendary origins of Loch Awe, from which Cruachan power station pumps water to the upper reservoir when there’s excess electricity on the grid.

The story claims the water washed a path through to the sea, creating the Pass of Brander. The site of a 1308 battle in the Scottish Wars of Independence, where Robert the Bruce defeated the English-aligned MacDougall and Macnaghten clans.

The mythical first section of the mural is separated by a Celtic-style cross from the modern second segment, which portrays the power station’s construction within Ben Cruachan. Here, four figures represent the four lead engineers of the project from the firms James Williamson & Partners, William Tawse Ltd, Edmund Nuttall Ltd and Merz & McLellan. They stand by the mountain, a roughly cut path running through its core.

At the base of the mural are the faces of 15 men lying on their sides. These are the  15 who were killed in  1962 when the ceiling of the turbine hall caved in during construction. Their uniform expressionless faces, however, turn them into symbols of the 30-plus workers who died while digging and blasting the power station’s tunnels and constructing the dam at the upper reservoir.

Next to this is a fairy tale portrayal of Queen Elizabeth II, who wears a gold grown and holds a sceptre from which electricity flows in a glowing lightning bolt through rock, commanding the power station into life.

The final third of the mural shows the whole power station system within the mountain. The upper reservoir sits nestled in the slopes of Ben Cruachan with water flowing down the mountain to the four turbines and Loch Awe below. Viewed as a whole, the mural takes the audience from mythology to the modern power station, which continues to play a vital role in the electricity system today.

Carving the Cruachan mural

The mural was created by artist Elizabeth Falconer, who was commissioned to create it to celebrate the power station’s opening by the Queen on 15 October 1965. At the time, only two of Cruachan’s four 100 megawatt (MW) reversible turbines were completed and operational, but it was still the first station of its kind to operate at such a scale. Two of the power station’s  turbines were modified with increased capacities meaning Cruachan can both use and generate up to 440 MW.

HRH Queen Elizabeth II opening Cruachan in 1965

HRH Queen Elizabeth II opening Cruachan on 15 October 1965

The project came to Falconer through her husband, a native of Aberdeen who worked as an architect partner to one of Cruachan’s engineering firms. The brief simply requested she create a piece to fill the empty space on the wall of the turbine hall. Deciding to dive into the history and mythology of the mountain, she initially carved the mural in London and only ventured into Hollow Mountain years after it was first put in place, to make renovations on the work.

Cruachan Power Station was a visionary idea and represented a considerable technical and engineering achievement when it opened. The designs and construction of the reversable turbines put this site at the cutting end of modern energy technology.

So, it’s fitting the mural appears distinctly modern in its design, yet tells a story that connects this modern power station to the ancient rock it lives within.

It’s Cruachan’s mural’s location inside the mountain that makes it so unique as a work of art. However, at a time when the electricity grid is changing to an increasingly renewable system, based more around weather and geography, the connections the mural makes between Scotland’s landscape and the modern power station, make it relevant beyond the turbine cavern.



Find out more about Cruachan Power Station

14 moments that electrified history

Electricity is such a universal and accepted part of our lives it’s become something we take for granted. Rarely do we stop to consider the path it took to become ubiquitous, and yet through the course of its history there have been several eureka moments and breakthrough inventions that have shaped our modern lives. Here are some of the defining moments in the development of electricity and power.

2750 BC – Electricity first recorded in the form of electric fish

Ancient Egyptians referred to electric catfish as the ‘thunderers of the Nile’, and were fascinated by these creatures. It led to a near millennia of wonder and intrigue, including conducting and documenting crude experiments, such as touching the fish with an iron rod to cause electric shocks.

500 BC – The discovery of static electricity

Around 500 BC Thales of Miletus discovered that static electricity could be made by rubbing lightweight objects such as fur or feathers on amber. This static effect remained unknown for almost 2,000 years until around 1600 AD, when William Gilbert discovered static electricity in earnest.

1600 AD – The origins of the word ‘electricity’

The Latin word ‘electricus’, which translates to ‘of amber’ was used by the English physician, William Gilbert to describe the force exerted when items are rubbed together. A few years later, English scientist Thomas Browne translated this into ‘electricity’ in his written investigations in the field.

1751 – Benjamin Franklin’s ‘Experiments and Observations on Electricity’

This book of Benjamin Franklin’s discoveries made about the behaviour of electricity was published in 1751. The publication and translation of American founding father, scientist and inventor’s letters would provide the basis for all further electricity experimentation. It also introduced a host of new terms to the field including positive, negative, charge, battery and electric shock.

1765 – James Watt transforms the Industrial Revolution

Watt studies Newcomen’s engine

James Watt transformed the Industrial Revolution with the invention of a modified Newcome engine, now known as the Watt steam engine. Machines no longer had to rely on the sometimes-temperamental wind, water or manpower – instead steam from boiling water could drive the pistons back and forth. Although Watt’s engine didn’t generate electricity, it created a foundation that would eventually lead to the steam turbine – still the basis of much of the globe’s electricity generation today.

James Watt’s steam engine

Alessandro Volta

1800 – Volta’s first true battery

Documented records of battery-like objects date back to 250 BC, but the first true battery was invented by Italian scientist Alessandro Volta in 1800. Volta realised that a current was created when zinc and silver were immersed in an electrolyte – the principal on which chemical batteries are still based today.

1800s – The first electrical cars

Breakthroughs in electric motors and batteries in the early 1800s led to experimentation with electrically powered vehicles. The British inventor Robert Anderson is often credited with developing the first crude electric carriage at the beginning of the 19th century, but it would not be until 1890 that American chemist William Morrison would invent the first practical electric car (though it closer resembled a motorised wagon), boasting a top speed of 14 miles per hour.

Michael Faraday

1831 – Michael Faraday’s electric dynamo

Faraday’s invention of the electric dynamo power generator set the precedent for electricity generation for centuries to come. His invention converted motive (or mechanical) power – such as steam, gas, water and wind turbines – into electromagnetic power at a low voltage. Although rudimentary, it was a breakthrough in generating consistent, continuous electricity, and opened the door for the likes of Thomas Edison and Joseph Swan, whose subsequent discoveries would make large-scale electricity generation feasible.

1879 – Lighting becomes practical and inexpensive

Thomas Edison patented the first practical and accessible incandescent light bulb, using a carbonised bamboo filament which could burn for more than 1,200 hours. Edison made the first public demonstration of his incandescent lightbulb on 31st December 1879 where he stated that, “electricity would be so cheap that only the rich would burn candles.” Although he was not the only inventor to experiment with incandescent light, his was the most enduring and practical. He would soon go on to develop not only the bulb, but an entire electrical lighting system.

Holborn Viaduct power station via Wikimedia

1882 – The world’s first public power station opens

Holborn Viaduct power station, also known as the Edison Electric Light Station, burnt coal to drive a steam turbine and generate electricity. The power was used for Holborn’s newly electrified streetlighting, an idea which would quickly spread around London.

1880s – Tesla and Edison’s current war

Nikola Tesla and Thomas Edison waged what came to be known as the current war in 1880s America. Tesla was determined to prove that alternating current (AC) – as is generated at power stations – was safe for domestic use, going against the Edison Group’s opinion that a direct current (DC) – as delivered from a battery – was safer and more reliable.

Inside an Edison power station in New York

The conflict led to years of risky demonstrations and experiments, including one where Tesla electrocuted himself in front of an audience to prove he would not be harmed. The war continued as they fought over the future of electric power generation until eventually AC won.

Nikola Tesla

1901 – Great Britain’s first industrial power station opens

Before Charles Mertz and William McLellan of Merz & McLellan built the Neptune Bank Power Station in Tyneside in 1901, individual factories were powered by private generators. By contrast, the Neptune Bank Power Station could supply reliable, cheap power to multiple factories that were connected through high-voltage transmission lines. This was the beginning of Britain’s national grid system.

1990s – The first mass market electrical vehicle (EV)

Concepts for electric cars had been around for a century, however, the General Motors EV1 was the first model to be mass produced by a major car brand – made possible with the breakthrough invention of the rechargeable battery. However, this EV1 model could not be purchased, only directly leased on a monthly contract. Because of this, its expensive build, and relatively small customer following, the model only lasted six years before General Motors crushed the majority of their cars.

2018 – Renewable generation accounts for a third of global power capacity

The International Renewable Energy Agency’s (IRENA) 2018 annual statistics revealed that renewable energy accounted for a third of global power capacity in 2018. Globally, total renewable electricity generation capacity reached 2,351 GW at the end of 2018, with hydropower accounting for almost half of that total, while wind and solar energy accounted for most of the remainder.

Breaking circuits to keep electricity safe

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.

What is LNG and how is it cutting global shipping emissions?

Oil tanker, Gas tanker operation at oil and gas terminal.

Shipping is widely considered the most efficient form of cargo transport. As a result, it’s the transportation of choice for around 90% of world trade. But even as the most efficient, it still accounts for roughly 3% of global carbon dioxide (CO2) emissions.

This may not sound like much, but it amounts to 1 billion tonnes of COand other greenhouse gases per year – more than the UK’s total emissions output. In fact, if shipping were a country, it would be the sixth largest producer of greenhouse gas (GHG) emissions. And unless there are drastic changes, emissions related to shipping could increase from between 50% and 250% by 2050.

As well as emitting GHGs that directly contribute towards the climate emergency, big ships powered by fossil fuels such as bunker fuel (also known as heavy fuel oil) release other emissions. These include two that can have indirect impacts – sulphur dioxide (SO2) and nitrogen oxides (NOx). Both impact air quality and can have human health and environmental impacts.

As a result, the International Maritime Organization (IMO) is introducing measures that will actively look to force shipping companies to reduce their emissions. In January 2020 it will bring in new rules that dictate all vessels will need to use fuels with a sulphur content of below 0.5%.

One approach ship owners are taking to meet these targets is to fit ‘scrubbers’– devices which wash exhausts with seawater, turning the sulphur oxides emitted from burning fossil fuel oils into harmless calcium sulphate. But these will only tackle the sulphur problem, and still mean that ships emit CO2.

Another approach is switching to cleaner energy alternatives such as biofuels, batteries or even sails, but the most promising of these based on existing technology is liquefied natural gas, or LNG.

What is LNG?

In its liquid form, natural gas can be used as a fuel to power ships, replacing heavy fuel oil, which is more typically used, emissions-heavy and cheaper. But first it needs to be turned into a liquid.

To do this, raw natural gas is purified to separate out all impurities and liquids. This leaves a mixture of mostly methane and some ethane, which is passed through giant refrigerators that cool it to -162oC, in turn shrinking its volume by 600 times.

The end product is a colourless, transparent, non-toxic liquid that’s much easier to store and transport, and can be used to power specially constructed LNG-ready ships, or by ships retrofitted to run on LNG. As well as being versatile, it has the potential to reduce sulphur oxides and nitrogen oxides by 90 to 95%, while emitting 10 to 20% less COthan heavier fuel alternatives.

The cost of operating a vessel on LNG is around half that of ultra-low sulphur marine diesel (an alternative fuel option for ships aiming to lower their sulphur output), and it’s also future-proofed in a way that other low-sulphur options are not. As emissions standards become stricter in the coming years, vessels using natural gas would still fall below any threshold.

The industry is starting to take notice. Last year 78 vessels were fitted to run on LNG, the highest annual number to date.

One company that has already embraced the switch to LNG is Estonia’s Graanul Invest. Europe’s largest wood pellet producer and a supplier to Drax Power Station, Graanul is preparing to introduce custom-built vessels that run on LNG by 2020.

The new ships will have the capacity to transport around 9,000 tonnes of compressed wood pellets and Graanul estimates that switching to LNG has the potential to lower its COemissions by 25%, to cut NOx emissions by 85%, and to almost completely eliminate SOand particulate matter pollution.  

Is LNG shipping’s only viable option?

LNG might be leading the charge towards cleaner shipping, but it’s not the only solution on the table. Another potential is using advanced sail technology to harness wind, which helps power large cargo ships. More than just an innovative way to upscale a centuries-old method of navigating the seas, it is one that could potentially be retrofitted to cargo ships and significantly reduce emissions.

Drax is currently taking part in a study with the Smart Green Shipping Alliance, Danish dry bulk cargo transporter Ultrabulk and Humphreys Yacht Design, to assess the possibility of retrofitting innovative sail technology onto one of its ships for importing biomass.

Manufacturers are also looking at battery power as a route to lowering emissions. Last year, boats using battery-fitted technology similar to that used by plug-in cars were developed for use in Norway, Belgium and the Netherlands, while Dutch company Port-Liner are currently building two giant all-electric barges – dubbed ‘Tesla ships’ – that will be powered by battery packs and can carry up to 280 containers.

Then there are projects exploring the use of ammonia (which can be produced from air and water using renewable electricity), and hydrogen fuel cell technology. In short, there are many options on the table, but few that can be implemented quickly, and at scale – two things which are needed by the industry. Judged by these criteria, LNG remains the frontrunner.

There are currently just 125 ships worldwide using LNG, but these numbers are expected to increase by between 400 and 600 by 2020. Given that the world fleet boasts more than 60,000 commercial ships, this remains a drop in the ocean, but with the right support it could be the start of a large scale move towards cleaner waterways.

What is a fuel cell and how will they help power the future?

A model fuel cell car

NASA Museum, Houston, Texas

How do you get a drink in space? That was one of the challenges for NASA in the 1960s and 70s when its Gemini and Apollo programmes were first preparing to take humans into space.

The answer, it turned out, surprisingly lay in the electricity source of the capsules’ control modules. Primitive by today’s standard, these panels were powered by what are known as fuel cells, which combined hydrogen and oxygen to generate electricity. The by-product of this reaction is heat but also water – pure enough for astronauts to drink.

Fuel cells offered NASA a much better option than the clunky batteries and inefficient solar arrays of the 1960s, and today they still remain on the forefront of energy technology, presenting the opportunity to clean up roads, power buildings and even help to reduce and carbon dioxide (CO2) emissions from power stations.

Power through reaction

At its most basic, a fuel cell is a device that uses a fuel source to generate electricity through a series of chemical reactions.

All fuel cells consist of three segments, two catalytic electrodes – a negatively charged anode on one side and a positively charged cathode on the other, and an electrolyte separating them. In a simple fuel cell, hydrogen, the most abundant element in the universe, is pumped to one electrode and oxygen to the other. Two different reactions then occur at the interfaces between the segments which generates electricity and water.

What allows this reaction to generate electricity is the electrolyte, which selectively transports charged particles from one electrode to the other. These charged molecules link the two reactions at the cathode and anode together and allow the overall reaction to occur. When the chemicals fed into the cell react at the electrodes, it creates an electrical current that can be harnessed as a power source.

Many different kinds of chemicals can be used in a fuel cell, such as natural gas or propane instead of hydrogen. A fuel cell is usually named based on the electrolyte used. Different electrolytes selectively transport different molecules across. The catalysts at either side are specialised to ensure that the correct reactions can occur at a fast enough rate.

For the Apollo missions, for example, NASA used alkaline fuel cells with potassium hydroxide electrolytes, but other types such as phosphoric acids, molten carbonates, or even solid ceramic electrolytes also exist.

The by-products to come out of a fuel cell all depend on what goes into it, however, their ability to generate electricity while creating few emissions, means they could have a key role to play in decarbonisation.

Fuel cells as a battery alternative

Fuel cells, like batteries, can store potential energy (in the form of chemicals), and then quickly produce an electrical current when needed. Their key difference, however, is that while batteries will eventually run out of power and need to be recharged, fuel cells will continue to function and produce electricity so long as there is fuel being fed in.

One of the most promising uses for fuel cells as an alternative to batteries is in electric vehicles.

Rachel Grima, a Research and Innovation Engineer at Drax, explains:

“Because it’s so light, hydrogen has a lot of potential when it comes to larger vehicles, like trucks and boats. Whereas battery-powered trucks are more difficult to design because they’re so heavy.”

These vehicles can pull in oxygen from the surrounding air to react with the stored hydrogen, producing only heat and water vapour as waste products. Which – coupled with an expanding network of hydrogen fuelling stations around the UK, Europe and US – makes them a transport fuel with a potentially big future.

Fuel cells, in conjunction with electrolysers, can also operate as large-scale storage option. Electrolysers operate in reverse to fuel cells, using excess electricity from the grid to produce hydrogen from water and storing it until it’s needed. When there is demand for electricity, the hydrogen is released and electricity generation begins in the fuel cell.

A project on the islands of Orkney is using the excess electricity generated by local, community-owned wind turbines to power a electrolyser and store hydrogen, that can be transported to fuel cells around the archipelago.

Fuel cells’ ability to take chemicals and generate electricity is also leading to experiments at Drax for one of the most important areas in energy today: carbon capture.

Turning COto power

Drax is already piloting bioenergy carbon capture and storage technologies, but fuel cells offer the unique ability to capture and use carbon while also adding another form of electricity generation to Drax Power Station.

“We’re looking at using a molten carbonate fuel cell that operates on natural gas, oxygen and CO2,” says Grima. “It’s basic chemistry that we can exploit to do carbon capture.”

The molten carbonate, a 600 degrees Celsius liquid made up of either lithium potassium or lithiumsodium carbonate sits in a ceramic matrix and functions as the electrolyte in the fuel cell. Natural gas and steam enter on one side and pass through a reformer that converts them into hydrogen and CO2.

On the other side, flue gas – the emissions (including biogenic CO2) which normally enter the atmosphere from Drax’s biomass units – is captured and fed into the cell alongside air from the atmosphere. The CO2and oxygen (O2) pass over the electrode where they form carbonate (CO32-) which is transported across the electrolyte to then react with the hydrogen (H2), creating an electrical charge.

“It’s like combining an open cycle gas turbine (OCGT) with carbon capture,” says Grima. “It has the electrical efficiency of an OCGT. But the difference is it captures COfrom our biomass units as well as its own CO2.”

Along with capturing and using CO2, the fuel cell also reduces nitrogen oxides (NOx) emissions from the flue gas, some of which are destroyed when the O2and CO2 react at the electrode.

From the side of the cell where flue gas enters a CO2-depleted gas is released. On the other side of the cell the by-products are water and CO2.

During a government-supported front end engineering and design (FEED) study starting this spring, this COwill also be captured, then fed through a pipeline running from Drax Power Station into the greenhouse of a nearby salad grower. Here it will act to accelerate the growth of tomatoes.

The partnership between Drax, FuelCell Energy, P3P Partners and the Department of Business, Energy and Industrial Strategy could provide an additional opportunity for the UK’s biggest renewable power generator to deploy bioenergy carbon capture usage and storage (BECCUS) at scale in the mid 2020s.

From powering space ships in the 70s to offering greenhouse-gas free transport, fuel cells continue to advance. As low-carbon electricity sources become more important they’re set to play a bigger role yet.

Learn more about carbon capture, usage and storage in our series:

Does electricity have a smell?

Freshly baked bread, newly cut grass, sizzling bacon. Many of the world’s most evocative smells often need electricity to make them, but does electricity itself have a smell?

The short answer is no. An electric current itself doesn’t have an odour. But in instances when electricity becomes visible or audible it also creates a distinctive smell.

“The smell electricity emits is the contents of the gasses created when electricity conducts through air,” says Drax Lead Engineer Gary Preece. “In an instance of a failure on a switch board, for example, and there’s a flash of electricity, gasses are created from the charged air including ozone.”

It’s the same ozone gas that makes up the lower layer of the earth’s atmosphere and is often described as having a clean, chlorine-like, but burnt, smell. While it can sometimes be dangerous, ozone is also a very useful gas.

What is ozone?

Ozone’s scientific name is trioxide as it is made up of three oxygen molecules. While the normal oxygen we breathe is O2, ozone is O3 and is created by electricity in a similar way to how it forms naturally in the atmosphere.

There are large amounts of oxygen and nitrogen floating around in the atmosphere protecting life on earth from the sun’s intense UV radiation. These rays are so powerful they can ionise the oxygen, ripping it apart into two individual molecules. However, these lonely molecules are highly reactive and will sometimes collide and bond with nearby O2 to create ozone.

An electric current at a high voltage – given the right conditions – will conduct through the air, ionising oxygen in its wake and creating ozone, just as the sun’s UV rays do. When electricity behaves like this it’s known as a corona discharge, which makes a crackling sound and creates a visible plasma.

The most common time people may come into contact with a whiff of ozone is when a storm is approaching. Lighting is essentially a massive plasma that creates ozone as it conducts through the air, with the smell often arriving before the storm hits. It highlights quite how pungent ozone is considering humans can smell it in concentrations as low as 10 parts per billion in ordinary air. 

The concerns and capabilities of ozone

While ozone protects the planet when it’s in the atmosphere, it can be dangerous at ground level where it can also form through naturally occurring gases reacting with air pollution sources. High exposure to ozone at ground level can lead to lung, throat and breathing problems. However, because it also has a damaging effect on bacteria, ozone can be very useful in the medical field, and electricity is being used to deliberately create it.

In fact, ozone has been experimented with in medicine for more than a century, with its ability to attack and kill bacteria making it useful as a disinfectant. During the First World War it was used to treat wounds and prevent them becoming inflamed and was also found to aid blood flow.

Electricity plays an important role in almost everything we interact with on a daily basis, affecting all our senses, even smell.

People strategy

Our people strategy: One Drax

Following extensive consultation with employees, we developed our people strategy to 2020 – One Drax. It has been designed to address the key issues that were raised by employees in our 2016 employee survey, such as the need for clearer learning and development programmes and more effective internal communications. The strategy focuses on valuing our people, driving business performance and developing talent to deliver our strategic and operational objectives.

We launched the five aspects of the strategy: my career, my performance, our behaviours, our reward, my recognition. In 2018, we will focus on all of these aspects and, in particular, our reward, my recognition and my career.

Behavioural framework

We have developed a number of HR programmes in line with our people strategy. The foundation of this is a new behavioural framework that identifies positive behaviours reflecting our Company values: honest, energised, achieving, together. The behaviours are integrated into all areas of our people management processes at Drax Group. The HR team consulted with one in five employees across the business, including senior leaders and union representatives, to develop the framework.

In 2018 we will further embed the behavioural framework and our Company values into our culture by developing an online tool for employees to evaluate how they demonstrate the behaviours.

Developing our people / apprenticeships

At Drax Power, we have a proud history of apprenticeships, with the majority remaining to work at Drax and progressing through the Company.


Mick Moore joined Drax on 7 September 1976 as a craft apprentice.

On completion of his apprenticeship, Mick continued to further his education and completed an HNC in Electrical & Electronic Engineering. After a 10-year break he resumed his further education, graduating from Humberside & Lincolnshire University with a degree in Electronics & Control Engineering, achieving Chartered Engineering status with the Institute of Electrical Engineers in 1999.

Having worked at Drax for 41 years, Mick’s career has included roles such as Instrument Mechanic, various engineering grades from Assistant Engineer to Process Control Engineer & Maintenance Section Head. Mick is now the Electrical, Control & Instrumentation Engineering Section Head for Drax Power and is currently responsible for a team of 51 people.


 

The wooden buildings of the future

Wooden building with blue sky background

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

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

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

Return of the treehouse

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

Horyu-ji Temple in Nara, Japan

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

Today, wood is once again finding favour.

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

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

Falling back in love with wood

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

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

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

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

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

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

Green giant

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

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

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

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

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