Tag: electricity generation

What is the national grid?

21 August 2020

Power generation
Electricity grid

What is the grid?

The national grid, or simply the grid, is the network of powerlines, pylons, gas lines and interconnectors that makes up Great Britain’s electricity and gas systems — and the engineers, technology and rules responsible for their seamless operation. It ensures electricity generated anywhere, by any source, can be transmitted to meet the demand for power wherever it’s needed across the country. It heats homes and businesses. It helps us to cook our food.

The national electricity grid consists of a high voltage transmission system, which connects electricity from power stations to substations and smaller local networks – called Distribution Network Operators, or DNOs – which transport electricity into homes and businesses.

Key national grid facts

How does it work?

Transporting electricity around the grid is more complicated than just connecting cables to power generators. In order to move power around the country, things like voltage and frequency of electricity must be balanced and kept uniform at all times. Without this, unstable electricity could damage equipment and ultimately lead to blackouts.

The National Grid Electricity System operator (ESO) is a separate entity from the National Grid company, and is responsible for maintaining the correct voltage, frequency and reserve power levels to ensure electricity is transmitted safely and efficiently at all times.

It does this by working with power generators and energy storage facilities to provide what are known as ‘ancillary services’ – a set of processes that keep the power system in operation, stable and balanced.

The national grid is the network of power stations, powerlines and electricity infrastructure that allows electricity to be generated, transported and used across the country.

Who controls it?

In Great Britain the National Grid company owns and operates the transmission systems which ensure electricity is delivered safely and reliably across the country.

The local distribution system is made up of 14 regional DNO companies, which deliver electricity at a lower voltage from substations to homes and businesses.

Great Britain’s grid incudes England, Scotland, Wales and several surrounding islands. Northern Ireland is part of an island-wide electricity system with the Republic of Ireland.

National grid fast facts

  • Great Britain’s grid is made up of more than 7,000 kilometres of cables, 90,000 pylons, 346 substations, and 1,500 kilometres of underground cables
  • Construction of the grid began on 14 July 1928 and was completed on 5 September 1933
  • It was originally designed to operate as 7 separate, connected grids, before a group of rebellion engineers attempted to run it as one on 29 October 1938. It has run as one grid ever since
  • A decade ago, Britain had 80 individual points of generation to manage. Today there are nearly one million
  • All electricity in Great Britain operates at a frequency of 50Hz. A deviation of just 1% above or below could cause damage

How is the grid changing?

As the sources that generate Great Britain’s electricity change to include more renewables, the grid has also changed.

The grid was built to work with large power stations that operate huge spinning turbines. With decarbonisation it’s evolved to include a greater variety of intermittent weather dependent sources such as wind, solar and decentralised power sources that serve individual buildings or communities.

This makes managing the grid’s stability more complicated, and requires the use of more ancillary services, usually delivered by flexible generators such as thermal power stations.

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What are ancillary services?

Power generation
Ancillary services

What are ancillary services?

Ancillary services are a set of processes that enable the transportation of electricity around the grid while keeping the power system operating in a stable, efficient and safe way.

Why do we need ancillary services? 

When electricity makes its way through the country, it needs to be managed so that the power generation and electricity useage levels are equal.

The regulating of elements such as frequency and voltage has to be carefully managed, so that the massive amounts of electricity moving – or transmitted – are able to be used safely in homes,  businesses, schools and hospitals around the country.

Ancillary services enable the power system to operate in a stable, efficient and safe way.

 What do ancillary services offer?

Ancillary services include a wide variety of electrical efficiency and safety nets, all focussed on ensuring the power system delivers enough output to meet demand yet remains stable:

Frequency: The UK’s power system runs at a frequency of 50 hertz – to stay balanced, it has to remain at that frequency. Turbines and generators adjust the speed at which they spin automatically to increase or decrease power in line with demand and ensure that the system is kept stable.

Voltage: Different parts of the UK’s transmission system use voltages of either 400, 275 or 132 kilovolts. To ensure that voltage remains within 5% of those figures at all times, to be safe for domestic electricity use, power stations can produce or re-absorb excess energy as reactive power, keeping the overall system reliable.

Inertia: Turbine use is important in keeping the system operating in its current state, even with disruptions and sudden changes. The electricity system uses the weight of heavy spinning turbines to create stability, acting as dampeners and smoothing out unexpected changes in frequency across the network.

Reserve: An important part of ancillary servicing is making sure that there are no surprises – so holding back powerto release if something unexpected happens means that the network can function confidently, knowing that there are generators and other power providers such as pumped hydro storage waiting ready to back it up.

Key facts about ancillary services

Who manages ancillary services?

In the UK the grid’s stability is managed by National Grid Electricity System Operator (ESO) – a  separate company of National Grid Electricity Transmission (ET). The ESO works with ancillary service providers to either sign long-term contracts or make short term requests for a service.

These partners are often power stations, such as Drax Power Station, which have large spinning turbines capable of controlling voltage, frequency, providing inertia and serving as a source of reserve power. 

What is the future of ancillary services, as we move to a more renewable system?

As the UK’s electricity system continues to change, so to do its requirements for different ancillary services. The switch from a few very large power stations to a greater variety of different electricity sources, some of which may be dependent on the weather, as well as changes in how the country uses electricity, means there is a greater need for ancillary services to keep the grid stable.

These services have historically been delivered by thermal power stations, but new innovations are enabling wind turbines to provide inertial response and overcome changes in frequency, and batteries to store reserve power that can then be supplied to the power system to ensure balance.

Ancillary Services

Ancillary services fast facts  

  • Batteries can in some cases be cheaper ancillary alternatives to conventional sources of energy. The Hornsdale Power Reserve, which runs on a Tesla battery in South Australia, lowered the price of frequency ancillary services by 90% after just four months of use.
  • Ancillary services usually work from habit; knowing when to slow electricity production, or increase supply based around the general public’s standard working hours, dinner time and the early morning rush.
  • But during the COVID-19 lockdown, electricity consumption on weekdays fell by 13% and so National Grid ESO had to intervene with ancillary services to keep the lights on.
  • Every year, the ESO’s ancillary services move 300 terawatt hours (TWh) of electricity, which is equal to 4 trillion kettles boiling at once.

With recent innovations around renewable energies, there are a wider variety of ways for ancillary services to generate power.

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Button: What is decarbonisation?

How electrical transformers work

17 July 2020

Power generation

Getting electricity safely and efficiently from generators, through power lines and across the country into our devices is a careful balancing act. One of the vital aspects of this is the voltage.

An electrical substation with transformers.

The National Grid’s transmission lines work at a voltage of 400,000 volts (v) and 275,000v, but if electricity were to enter homes at this voltage it would quickly damage anything it powered. Instead, regional distributors deliver electricity into homes at a much lower level of 230v.

Achieving a voltage level that’s safe to use requires stepping it up or down through transformers – huge pieces of electrical grid equipment that use a simple idea to have a big impact.

Why we need transformers

Voltage is like water pressure. Having high voltage transmission lines means the charged electrons that make up electricity are moving very efficiently through the system, with less energy being lost as heat along the way. However, that same ‘pressure’ is too much for just charging a phone. It would likely overload the device’s circuits and leave the user with a smouldering mess.

That’s where transformers step in. Electricity is produced at a variety of voltages around Great Britain, depending on different types of generation. In order to send it to where the demand is without losing too much energy as heat along the journey, a transformer attached to large power generators such as Drax’s biomass power plant or Beatrice offshore wind farm increases the voltage to 400,000v or 275,000v. The voltage depends on what part of the national transmission system the power station is connected to.

When the electricity arrives via pylons at a particular region of Great Britain, another transformer brings the voltage down to 132,000v for the regional distribution system. Subsequently, another reduces it to 11,000v in towns and villages, before a final transformer reduces the voltage to a safe 230v for use in homes and businesses.

Keeping the voltage high is useful in preventing energy loss to heat, but it also does something else important to the electricity shooting around the country.

Keeping voltage high to cut down current

If voltage is the water pressure, then current is the actual water particles moving through the pipes. In electrical terms the current is the charged electrons that actually power our lights and devices.

When these electrons travel along the electricity grid’s cables, they face resistance (imagine a partial blockage in a water pipe) this causes some electrical energy to be lost to heat. Getting the right amount of electricity needed around the country means keeping energy loss as low as possible. If the current is lower, fewer charged electrons are bumping into resistance at any one point in the system and less electrical energy is being lost.

Conveniently for the grid, raising the voltage of electricity causes the current to decrease and vice versa. How transformers actually do this is all a matter of coils. 

Super transformer at Cruachan Power Station

Transformer at Cruachan Power Station

Winding voltage up and down

Transformers work using the principal of electromagnetic induction, something the British scientist Michael Faraday first realised in 1831. He noticed that when a magnet moved through a coil of copper wires, a current flowed through those wires. It’s this same principal that enables spinning turbines to generate electricity today.

Michael Faraday

Michael Faraday

Similarly, when a current flows through a copper coil wrapped around an iron core, the core becomes magnetic.

Faraday did experiment with running currents through multiple copper coils, but it was scientist and Irish priest Father Nicholas Callan who in 1836 discovered the underlying principal of many of the world’s transformers today. He found if two separate sets of copper wires were wound around each end of an iron core and an electrical current was passed through one of them (the primary winding) then a magnetic field is created that causes an electric current to flow in the secondary winding.

However, things change depending on how many times each wire is wound around the core. If there are more turns in the secondary winding than the primary one, then when a current is induced the voltage increases. When there are fewer turns in the secondary winding than the primary, the voltage decreases.

Callan's Induction Coil

Callan’s Induction Coil (1845)

Moreover, Father Callan discovered that the increase or decrease in voltage is directly proportional to the number of turns in the windings. So, theoretically, if an electrical current with a voltage of 5v is passed through a primary winding with 10 turns and creates a current in a secondary winding with 20 turns, the voltage will also double, in this case to 10v.

Father Callan’s invention is known as an induction coil, where the two sets of windings share a long, thick iron rod. Since then the transformer has undergone continual revision, optimisation and specialisation for different use cases. However, the underlying principal of using electromagnetic induction to increase and decrease voltage remains the same.

From homes to power stations

One of the most common types of transformers are distribution transformers – the kind often found on utility poles near homes. These transformers perform the final step down from local distribution systems to 230v as the electricity enters homes and businesses.

These often use an iron core that takes the form of a hollow square with windings wrapped around both ends. When a current passes through and magnetises the core it causes it to expand and contract in a process known as magnetostriction, which sometimes causes enough vibration to produce an audible hum.

A transformer being moved from Longannet to Cruachan Power Station in 2019.

A transformer being moved from Longannet to Cruachan Power Station in 2019.

In these type of transformers it’s safe for the current to be transferred through the air between the two windings, but when higher voltages are being used, such as at Cruachan Power Station – the biggest pumped storage facility in Scotland – different approaches are needed. Large power station-scale transformers are submerged in a special insulating oil inside a metal container. The oil provides electrical insulation to prevent short circuits while also cooling the core and windings, preventing damage and failure.

Even as the main sources of Great Britain’s electricity change from coal and nuclear power stations to wind farms and solar panels, transformers will remain an essential part of the grid, in getting the right amount of power to where we need it – fast.

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.

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 is net zero?

21 January 2020

Carbon capture
Skyscraper vertical forest in Milan

For age-old rivals Glasgow and Edinburgh, the race to the top has taken a sharp turn downwards. Instead, they’re in a race to the bottom to earn the title of the first ‘net zero’ carbon city in the UK.

While they might be battling to be the first in the UK to reach net zero, they are far from the only cities with net zero in their sights. In the wake of the growing climate emergency, cities, companies and countries around the world have all announced their own ambitions for hitting ‘net zero’.

It has become a global focus based on necessity – for the world to hit the Paris Agreement targets and limit global temperature rise to under two degrees Celsius, it’s predicted the world must become net zero by 2070.

Yet despite its ubiquity, net zero is a term that’s not always fully understood. So, what does net zero actually mean?

Glasgow, Scotland. Host of COP26.

What does net zero mean?

‘Going net zero’ most often refers specifically to reaching net zero carbon emissions. But this doesn’t just mean cutting all emissions down to zero.

Instead, net zero describes a state where the greenhouse gas (GHG) emitted [*] and removed by a company, geographic area or facility is in balance.

In practice, this means that as well as making efforts to reduce its emissions, an entity must capture, absorb or offset an equal amount of carbon from the atmosphere to the amount it releases. The result is that the carbon it emits is the same as the amount it removes, so it does not increase carbon levels in the atmosphere. Its carbon contributions are effectively zero – or more specifically, net zero.

The Grantham Research Institute on Climate Change and the Environment likens the net zero target to running a bath – an ideal level of water can be achieved by either turning down the taps (the mechanism adding emissions) or draining some of the water from the bathtub (the thing removing of emissions from the atmosphere). If these two things are equally matched, the water level in the bath doesn’t change.

To reach net zero and drive a sustained effort to combat climate change, a similar overall balance between emissions produced and emissions removed from the atmosphere must be achieved.

But while the analogy of a bath might make it sound simple, actually reaching net zero at the scale necessary will take significant work across industries, countries and governments.

How to achieve net zero

The UK’s Committee on Climate Change (CCC) recommends that to reach net zero all industries must be widely decarbonised, heavy good vehicles must switch to low-carbon fuel sources, and a fifth of agricultural land must change to alternative uses that bolster emission reductions, such as biomass production.

However, given the nature of many of these industries (and others considered ‘hard-to-treat’, such as aviation and manufacturing), completely eliminating emissions is often difficult or even impossible. Instead, residual emissions must be counterbalanced by natural or engineered solutions.

Natural solutions can include afforestation (planting new forests) and reforestation (replanting trees in areas that were previous forestland), which use trees’ natural ability to absorb carbon from the atmosphere to offset emissions.

On the other hand, engineering solutions such as carbon capture usage and storage (CCUS) can capture and permanently store carbon from industry before it’s released into the atmosphere. It is estimated this technology can capture in excess of 90% of the carbon released by fossil fuels during power generation or industrial processes such as cement production.

Negative emissions essential to achieving net zero

Click to view/download graphic. Source: Zero Carbon Humber.

Bioenergy with carbon capture and storage (BECCS) could actually take this a step further and lead to a net removal of carbon emissions from the atmosphere, often referred to as negative emissions. BECCS combines the use of biomass as a fuel source with CCUS. When that biomass comes from trees grown in responsibly managed working forests that absorb carbon, it becomes a low carbon fuel. When this process is combined with CCUS and the carbon emissions are captured at point of the biomass’ use, the overall process removes more carbon than is released, creating ‘negative emissions’.

According to the Global CCS Institute, BECCS is quickly emerging as the best solution to decarbonise emission-heavy industries. A joint report by The Royal Academy of Engineering and Royal Society estimates that BECCS could help the UK to capture 50 million tonnes of carbon per year by 2050 – eliminating almost half of the emissions projected to remain in the economy.

The UK’s move to net zero

In June 2019, the UK became the first major global economy to pass a law to reduce all greenhouse gas emissions to net zero by 2050. It is one of a small group of countries, including France and Sweden, that have enacted this ambition into law, forcing the government to take action towards meeting net zero.

Electrical radiator

Although this is an ambitious target, the UK is making steady progress towards it. In 2018 the UK’s emissions were 44% below 1990 levels, while some of the most intensive industries are fast decarbonising – June 2019 saw the carbon content of electricity hit an all-time low, falling below 100 g/kWh for the first time. This is especially important as the shift to net zero will create a much greater demand for electricity as fossil fuel use in transport and home heating must be switched with power from the grid.

Hitting net zero will take more than just this consistent reduction in emissions, however. An increase in capture and removal technologies will also be required. On the whole, the CCC predict an estimated 75 to 175 million tonnes of carbon and equivalent emissions will need to be removed by CCUS solutions annually in 2050 to fully meet the UK’s net zero target.

This will need substantial financial backing. The CCC forecasts that, at present, a net zero target can be reached at an annual resource cost of up to 1-2% of GDP between now and 2050. However, there is still much debate about the role the global carbon markets need to play to facilitate a more cost-effective and efficient way for countries to work together through market mechanisms.

Industries across the UK are starting to take affirmative action to work towards the net zero target. In the energy sector, projects such as Drax Power Station’s carbon capture pilots are turning BECCS increasingly into a reality ready to be deployed at scale.

Along with these individual projects, reaching net zero also requires greater cooperation across the industrial sectors. The Zero Carbon Humber partnership between energy companies, industrial emitters and local organisations, for example, aims to deliver the UK’s first zero carbon industrial cluster in the Humber region by the mid-2020s.

Nonetheless, efforts from all sectors must be made to ensure that the UK stays on course to meet all its immediate and long-term emissions targets. And regardless of whether or not Edinburgh or Glasgow realise their net zero goals first, the competition demonstrates how important the idea of net zero has become and society’s drive for real change across the UK.

Drax has announced an ambition to become carbon negative by 2030 – removing more carbon from the atmosphere than produced in our operations, creating a negative carbon footprint. Track our progress at Towards Carbon Negative.

[*] In this article we’ve simplified our explanation of net zero. Carbon dioxide (CO2) is the most abundant greenhouse gas (GHG). It is also a long-lived GHG that creates warming that persists in the long term. Although the land and ocean absorb it, a significant proportion stays in the atmosphere for centuries or even millennia causing climate change. It is, therefore, the most important GHG to abate. Other long-lived GHGs include include nitrous oxide (N2O, lifetime of circa 120 years) and some F-Gasses (e.g. SF6 with a lifetime of circa 3,200 years). GHGs are often aggregated as carbon dioxide equivalent (abbreviated as CO2e or CO2eq) and it is this that net zero targets measure. In this article, ‘carbon’ is used for simplicity and as a proxy for ‘carbon dioxide’, ‘CO2‘, ‘GHGs’ or ‘CO2e’.

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.