Tag: electricity generation

4 of the longest running electrical objects

15 June 2020

Electrification

How long do your electrical devices last? We’re not talking about battery life, but the overall lifetime of the items we use every day that are powered by electricity.

It’s accepted that today’s electrical devices have short life spans, in part a symptom of rapidly evolving technology fuelling the need for constant consumer updates and in part a result of planned obsolescence (devices being manufactured to fail within a set number of years to encourage repeat purchases). Electrical devices aren’t purchased with the belief they will last a lifetime.

But it hasn’t always been this way. Before rapid technological development and the rise of fast consumerism, devices were built to last.

Over the relatively short history of electrical appliances, there are tools and equipment that have operated for decades. Some of these remain in operation today with hardly any alterations, but for a few tweaks here and there to upgrade or preserve.

Built to last, here are a few of the longest running electrical inventions.

The Oxford Electric Bell located in the Clarendon Laboratory, University of Oxford.

1840 – The Oxford Electric Bell

The Oxford Electric Bell is not your typical bell – not just in how it looks, but in the fact it has been in constant operation since the mid 19th Century. It consists of two primitive batteries called ‘dry piles’ with bells fitted at each end and a metal ball that vibrates between them to very quietly, continuously ring.

Its original purpose is unidentified, but what is known is that the bell is the result of an experiment put on by the London instrument-manufacturing firm Watkins and Hill in 1840. Acquired by Robert Walker, a physics professor at the University of Oxford in the mid 1800s, it’s displayed at Oxford’s Clarendon Laboratory which explains why it’s also known as the Clarendon Pile.

The exact make-up of the dry piles is unknown, as no one wants to tamper with them to investigate their composition out for fear of ending the bell’s 179-year-long streak. As a result, confusion remains as to why The Oxford Electric Bell has remained in operation for so long.

Souter Lighthouse, Tyneside, England.

1871 – Souter Lighthouse in South Shields, UK

The lamp in the Souter lighthouse, situated between the rivers Tyne and Wear, was the most advanced of its day when it was first constructed. Designed to use an alternating electric current, it was the first purpose-built, electrically powered lighthouse in the world. Although no longer in operation today, it ran unchanged for nearly 50 years.

The light was generated using carbon arc lamps, and it originally produced a beam of red light that would come on once every five seconds.

Souter’s original lamp operated unchanged from 1871 to 1914, when it was replaced by more conventional oil lamps. It was altered again to run on mains electric power in 1952 and was finally deactivated in 1988.

1896 – The Isle of Man’s Manx Electric Railway

Tourism hit the Isle of Man in the 1880s and with it came the construction of hotels and boarding houses. Two businessmen saw this as an opportunity to purchase a large estate on the island and develop it into housing and a pleasure development. The Manx Parliament approved the sale in 1892 on one condition: that a road and a tramway be built to give people access.

Snaefell mountain railway station, Isle of Man.

It was decided that the tram would be electric, and work began in the spring of 1893, with the tram system up and running by September of that year. Although the track and its cars have been extended and updated over time, the first three cars remain the longest running electric tramcars in the world.

Photograph by Dick Jones (centennialbulb.org)

1902 – The Centennial Bulb

The unassuming Centennial Bulb has been working in the Livermore, California Fire Department for 117 years. The bulb was first installed in 1902 in the department’s hose cart house, but was later moved to Livermore’s Fire Station 6, where it has been illuminated for more than a million hours.

Throughout its life the Centennial Bulb has seen just two interruptions: for a week in 1937 when the Firehouse was refurbished, and in May 2013 when it was off for nine and a half hours due to a failed power supply. Made by the Shelby Electric Company, the hand-blown bulb previously shone at 60 watts but has since been dimmed to 4 watts.

While this means it isn’t able to actually illuminate much, it is a reminder that despite the disposable nature of many modern electrical devices, it’s possible to build electrical items that last.

Is renewable-rich the new oil-rich?

2 June 2020

Power generation
Aerial view of hundreds solar energy modules or panels rows along the dry lands at Atacama Desert, Chile. Huge Photovoltaic PV Plant in the middle of the desert from an aerial drone point of view

We’re all familiar with the phrase ‘oil-rich’ nations, but as low carbon energy sources become ever more important to meeting global demand, renewable energy could become a global export. With a future favouring zero-carbon and even negative emissions innovation, here are some countries that are not only harnessing their natural resources to make more renewable energy, but are making progress in storing and exporting it.

Could these new opportunities lead us to one day deem them ‘renewable-rich’?

Could Europe import its solar power supply?

With the largest concentrated solar farm in the world, Morocco is already streets ahead in its ability to capture and convert sunlight into power. The 3,000 hectare solar complex, known as Noor-Ouarzazate, has a capacity of 580 megawatts (MW), which provides enough power for a city twice the size of Marrakesh.

Noor-Ouarzazate Power Plant, Morocco. Image source: ACWA Power

Its uses curved mirrors to direct sunlight into a singular beam that creates enough heat to melt salt in a central tower. This stores the heat and – when needed – is used to create steam which spins a turbine and generates electricity. This has helped keep Morocco on course to achieve its goal of deriving 42% of its power from renewable sources by the end of 2020, which potentially means a surplus in the coming years.

Morocco already has 1.4 gigawatts (GW) of interconnection with Spain, and another 700 MW is scheduled to come online before 2026. The country’s close proximity to Europe could make its solar capacity a source of power across the continent.

Africa’s geothermal potential

Olkaria II geothermal power plant in Kenya

Kenya was the first African nation to embrace geothermal energy and has now been using it for decades. In 1985, Kenya’s geothermal generation produced 45 MW of power – 30 years later, the country now turns over 630 MW.

Kenya’s ample generation of geothermal electricity is due to an abundance of steam energy in the underground volcanic wells of Olkaria, in the Great Rift Valley. In 2015, the region was responsible for providing 47% of the country’s power.

Currently the Olkaria region is thought to have a potential capacity of 2 GW of power, which could help to provide a source of clean energy for Kenya’s neighbours. However, there is potential for the rest of East Africa to generate its own geothermal power.

In this region of the continent there is an estimated 20 GW of power generation capacity possible  from stored geothermal energy, while the demand for the creation of usable grids that can connect multiple countries is high. Kenya is currently expanding its own grid, installing a planned 3,600 miles of new electrical wiring across the country.

Winds of change

China’s position in the renewable energy market is already up top, with continuous investment in solar and hydro power giving it a renewable capacity of more than 700 GW

The country is also home to the world’s largest onshore wind farm, in the form of the Gansu Wind Farm Project, which is made up of over 7,000 turbines. It is set to have a capacity of 20 GW by the end of 2020, bringing the nationwide installed wind capacity to 250 GW.

With China exporting more than 20,000 gigawatt-hours (GWh) of electricity in 2018, large scale renewable projects can have a wide-reaching effect beyond its borders. South-Asia is the primary market, but excesses of power in Western China have stoked ideas of exporting power as far away as Germany.

Can the US store the world’s carbon?

In the quest for zero-carbon energy it won’t just be nations that can export excess energy that could stand to profit – those that can import emissions could also benefit.

While many countries are developing the capabilities to capture carbon dioxide (CO2), storing it safely and permanently is another question. Having underground facilities that can store CO2 creates an opportunity to import and sequester carbon as a service for other nations. Norway is already doing it, but the US has the greatest potential thanks to its abundance of large underground storage capabilities.

The Global CCS Institute highlights the US as the country most prepared to deploy carbon capture and storage (CCS) at scale, thanks to its vast landscape, history of injecting CO2 in enhanced oil recovery, and favourable government policies.

The Petra Nova plant in Texas is also known as the world’s largest carbon capture facility. The coal-power station captured more than 1 million tonnes of CO2 within the first 10 months of operating as a 654 MW unit.

Carbon capture facility at the Petra Nova coal-fired power plant, Texas, USA

Chile’s hydrogen innovation

Hydrogen is becoming increasingly relevant as an energy source thanks to its ability to generate electricity and power transport while releasing far fewer emissions than other fossil fuels.

Chile was an early proponent of energy sharing with its hydrogen programme. The country uses solar electricity generated in the Atacama Desert (which sees 3,000 hours of sunlight a year), to power hydrogen production in a process called electrolysis, which uses electricity to split water into oxygen and hydrogen.

Chile plans to export the gas to Japan and South Korea, but with global demand for hydrogen set to grow, higher-volume, further-reaching exporting of the country’s hydrogen could soon be on the way.

Going forward, these green innovations – from carbon storage to geothermal potential – could increasingly be shared between countries and continents in an attempt to lower the overall carbon footprint of the world’s energy. This could create a global power shift toward nations which, rather than having high capacity for fossil fuel extraction, can instead use a different set of natural resources to generate, store and export cleaner energy.

14 moments that electrified history

13 May 2020

Electrification

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

6 March 2020

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

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

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

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

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

Circuits within circuits 

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

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

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

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

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

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

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

Fuses and circuit breakers

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

One electrical fuse on electronic circuit background

An electrical fuse

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

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

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

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

Protecting generators at grid scale 

Power circuit breakers for a high-voltage network

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

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

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

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

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

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

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

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

A 400kV circuit breaker on the Drax Power Station site

A 400kV circuit breaker on the Drax Power Station site

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

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

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

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

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

A 3300 Volt circuit breaker at Drax Power Station

A 3300 Volt circuit breaker at Drax Power Station

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

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

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

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

How river-powered hydro schemes work

21 February 2020

Power generation
Waterflow outside Glenlee Power Station

Hydro power is one of the most widespread sources of electricity generation in the world – it is also one of the biggest. Nine of the world’s ten largest power stations are hydro powered. Facilities such as the Three Gorges Dam on China’s Yangtze River and the Itaipu Dam (pictured below) on the Brazil-Paraguay border are capable of generating massive amounts of electricity.

Itaipu Dam, hydroelectric power station on the Brazil-Paraguay border

But hydropower can also be very effective at a smaller, more local level, using relatively small rivers. These smaller hydro facilities can bring renewable electricity to remote areas and serve local needs. All they need is an abundance of flowing water to spin their turbines.

In Scotland, two schemes are making use of the country’s plentiful water sources to help the local community, the economy and the surrounding environment.

Turning river waterflow into power

The Lanark and Galloway hydropower schemes are both located in rural Scotland and have been generating power for nearly a century. Despite being more than 95 kilometres apart, they operate in very similar ways.

Lanark (which includes two power stations – Bonnington, with a capacity of 11 MW, and Stonebyres, with a capacity of 6 MW) sits on the River Clyde and began generating power in 1926, making it one of the oldest hydro-electric plants in Great Britain.

Galloway soon followed, coming online in the mid-1930s. It includes a total of six power stations – Glenlee, Tongland, Kendoon, Drumjohn, Earlstoun and Carsfad – eight dams and a network of tunnels and pipelines, giving it a capacity of 109 MW.

Kendoon Power Station Turbine Hall

Kendoon Power Station Turbine Hall

“There was always potential for hydro in the Galloway Hills but there wasn’t demand for 100 MW of power,” explains Stuart Ferns, Operations and Maintenance Manager on the Lanark and Galloway hydro schemes. “However, when the national grid was established in the 1920s it enabled surplus power to be transmitted beyond the local area to Glasgow and further afield.”

Unlike Lanark, which is situated about halfway down the River Clyde, the Galloway scheme spans the entirety of its river system from Loch Doon in the North to Tongland in the south. Both, however, cover a similarly sized catchment area of roughly 1,000 square kilometres.

Where they do differ is in the type of hydropower they generate and the needs they serve for their regions and the wider electricity grid.

Tongland Dam

Tongland Dam

Lanark’s power stations generate electricity through what’s called ‘run-of-the-river’ hydropower, which describes a scheme where there is no dam to stop and store water along the river.

Instead, water from a flowing river is diverted into a power station situated alongside the river. Here the water is used to spin a turbine connected to a generator, before being returned back to the river. Lanark’s two power stations are both positioned alongside naturally occurring waterfalls, which allow them to take advantage of the natural gravitational pressure.

“The Lanark stations run constantly,” says O&M Manager Stuart Ferns. “They will run as long as there is water in the river. And generally, there is always some water available.”

The Galloway system is different. It only generates power when there are peaks in electricity demand. To do this it operates a conventional storage hydro scheme where dams situated along the river are used to create small reservoirs. When demand for electricity peaks – typically between 5pm and 7pm – water is released from these reservoirs and used to spin turbines and generate electricity.

During the day both schemes are monitored and controlled from Glenlee Power Station, halfway down the Galloway route. As night falls, responsibility instead falls to the control room at Cruachan Power Station, more than 200 kilometres away. Around-the-clock monitoring in this way is important as the uncertainty of Scotland’s weather can have effects on the schemes, and on their surrounding environment.

Penstocks leading to Glenlee Power Station

Penstocks leading to Glenlee Power Station

Working with the landscape

Dumfries & Galloway and Lanarkshire are regions defined and dominated by their river systems. As such, extreme weather can lead to occasional natural flooding. The Lanark and Galloway schemes not only have to be diligent in working with extreme weather, but they can actually play a role in monitoring and managing it.

“The Galloway reservoirs help to alleviate flooding because they can store water and help to alleviate flooding downstream,” says Ferns.

Staff at the scheme work closely with local authorities, landowners and the Scottish Environment Protection Agency (SEPA), sharing their weather forecasting and reservoir level data to help them predict which areas will be affected and when roads might need to be closed or even villages evacuated.

The team takes a similar approach to monitoring and protecting the local wildlife. Fish, such as north Atlantic salmon and trout, migrate upstream from the ocean through the Galloway Rivers using manmade fish passes (also known as ‘fish ladders’), which allow fish to bypass dams along the scheme.

Lanark hydro site, River Clyde

Waterfalls on the Clyde at Lanark

Lanark’s natural waterfalls mean it is not a route taken by migratory fish. However, ensuring there is always enough water in the rivers to protect fish and plant life factors into how both schemes operate with the landscape.

Working with the wildlife, weather and surrounding environment of the two rivers have always been a part of running the Lanark and Galloway schemes. Their continued role in the region’s electricity system highlights the relevancy of small-scale hydropower, even as demand for electricity grows.

What makes a country’s electricity system stable?

23 December 2019

Power generation

How reliable is Great Britain’s electricity system? Across the country electricity is accessible and safe to use for just about everyone, every day. Wide-scale blackouts are very rare, but they do happen.

On 9 August 2019 a power cut saw more than 1 million people and services lose power for just under an hour. It was the first large-scale blackout since 2013. Although this proves the network is not infallible, the fact it was such an outlier in the normal performance of the grid highlights its otherwise exemplary stability and reliability.

But what is it exactly that makes an electricity system stable and reliable?

At its core, system stability comes down to two key factors: a country or region’s ability to generate enough electricity, and its ability to then transport it through a transmission system to where it’s needed.

When everything is running smoothly an electricity system is described as being ‘balanced’. In this state supply meets demand exactly and all necessary conditions – such as voltage and frequency – are right for the safe and efficient transport of electricity. Any slight deviation or mismatch across any of these factors can cause power stations or infrastructure to trip and cut off power.

A recent report by Electric Insights identified the countries around the world with most reliable power systems, in which the UK was fourth. It offers an insight into what factors contribute to building a stable system, as well as those that hold some countries back.

Generation and reliable infrastructure  

According to the report, France has the most reliable electricity system of any country with a population of more than five million people, having gone a decade without a power outage. One reason for this is the country’s fleet of 58 state-controlled nuclear power stations which generate huge amounts of consistent baseload power.

In 2017 nuclear power made up more than 70% of France’s electricity generation while hydropower accounted for another 10% of the 475 Terawatt hours (TWh) consumed across the county that year.

Penly Nuclear Power Station near Dieppe, France.

Now, as its nuclear stations age, France is increasing its renewable power generation. As these sources are often weather dependent, imports from and exports to its neighbours are expected to become a more important part of keeping the French network stable at times when there is little sunlight or wind – or too much.

Importing and exporting electricity is also key to Switzerland’s power system (third most reliable network on the list), with 41 border-crossing power lines allowing the country to serve as a crossroads for power flowing between Italy and Germany. It means its total imports and exports can often exceed electricity production within the country.

Electricity pylons in Switzerland.

Switzerland’s mountainous landscape also means ensuring a reliable electricity system requires a carefully maintained transmissions system. The Swiss grid is 6,700 kilometres long and uses 40,000 hi-tech metering points along it to record and process around 10,000 data points in seconds.

The key to the stability of South Korea – the second most stable network on the list – is also its imports, but rather than actual megawatts it comes in the form of oil, gas and coal. The country is the world’s fourth biggest coal importer and its coal power stations account for 42% of its total generation.

Seoul, South Korea.

However, in the face of urban smog issues and global decarbonisation goals it is pursuing a switch to renewables. This can come with repercussions to stability, so South Korea is also investing in transmission infrastructure, including a new interconnector from the east of the country to Seoul, its main source of electricity consumption.

It highlights that if decarbonisation is going to accelerate at the pace needed to meet Paris Agreement targets, then many of the world’s most stable and reliable electricity systems need to go through significant change. Balance will be needed between meeting decarbonisation targets with overall system stability.

However, there are many countries around the world that focus less on ensuring consistent stability through decarbonisation and are instead more focused on how to achieve stability in the first place.

Stalling generation

The Democratic Republic of Congo is the eleventh-largest country on earth. It is rich with minerals and resources, yet it is the least electrified nation. Just 9% of people have access to power (in rural areas that number drops to just 1%) and the country suffers blackouts more than once a month as a result of ‘load shedding’, when there isn’t enough power to meet demand so parts of the grid are deliberately shut down to prevent the entire system failing.

Currently, the country has just 2.7 GW of installed electricity capacity, 2.5 GW of which comes from hydropower. The country’s Inga dam facility on the Congo river has the potential to generate more electricity than any other single source of power on the planet (it’s thought the proposed Grand Inga site could produce as much as 40 GW, twice that of China’s Three Gorges Dam) and provide electricity to a massive part of southern Africa. A legacy of political instability in the country, however, has so far made securing financing difficult.

Congo River, Democratic Republic of Congo.

Nigeria is one of the world’s fastest growing economies, and with that comes rapidly rising demand for electricity. However, just 45% of the country is currently electrified, and of these areas, many still suffer outages at least once a month. The country has 12.5 GW of installed capacity, most of which comes from thermal gas stations, but technical problems in power stations and infrastructure, mean it is often only capable of generating as much as 5 GW to transmit on to end consumers.

This limited production capability means it often fails to meet demand, resulting in outages. The problem has been prolonged by struggling utility companies that are unable to make the investments needed to stabilise electricity supply.

Keen to resolve what it has referenced as an ‘energy supply crisis’, the Nigerian government recently secured a $1 billion credit line from the World Bank to improve access to electricity across the country.

The investment will focus in part on securing the transmission system from theft, thus allowing the private utility companies to generate the revenue needed to improve generation.

Transmission holding back emerging systems

Balancing transmissions systems is a crucial part of stable electricity networks. Maintaining a steady frequency that delivers safe, usable electricity into homes and businesses is at the crux of reliability. Even countries that can generate enough electricity are held back if they can’t efficiently get the electricity to where it is needed.

Brazil has an abundance of hydropower installed. Its 97 GW of hydro accounts for more than 70% of the country’s electricity mix. However, the country’s dams are largely concentrated around the Amazon basin in the North West, whereas demand comes from cities in the south and eastern coastline. Transporting electricity across long distances between generator and consumer makes it difficult to maintain the correct voltage and frequency needed to keep a stable and reliable flow of electricity. As a result, Brazil suffers a blackout every one-to-three months.

Hydropower plant Henry Borden in the Serra do Mar, Brazil.

The country is tackling its transmissions problems by diversifying its electricity mix to include greater levels of solar and wind off its east coast – closer to many of its major cities. The country has also looked to new technology for solutions.

At the start of the decade as much as 8% of all electricity being generated in Brazil was being stolen, reaching as high as 40% in some areas. These illegal hookups both damage infrastructure, making it less reliable, as well as blur the true demand, making grid management challenging.

Brazil has since deployed smart meters to measure electricity’s journey from power stations to end users more accurately, allowing operators to spot anomalies sooner. Electricity theft is a major problem in many developing regions, with as much as $10 billion worth of power lost each year in India, which suffers blackouts as often as Brazil.

It highlights that even when there is generation to meet demand, maintaining stability at a large scale requires constant attention and innovation as new challenges arise.

This looks different around the world. Some countries might face challenges in shifting from stable thermal-based systems to renewables, others are attempting to build stability into newly connected networks. But no matter where in the world electricity is being used, ensuring reliability is an ever-ongoing task.

Electric Insights is commissioned by Drax and delivered by a team of independent academics from Imperial College London, facilitated by the college’s consultancy company – Imperial Consultants. The quarterly report analyses raw data made publicly available by National Grid and Elexon, which run the electricity and balancing market respectively, and Sheffield Solar. Read the full Q3 2019 Electric Insights report or download the PDF version.

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.

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

27 June 2019

Carbon capture

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 CO2 to 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 CO2 from 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 CO2 will 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: