Tag: renewable energy

Supporting a circular economy in the forests

Every year in British Columbia, millions of tonnes of waste wood – known in the industry as slash – is burned by the side of the road.

Land managers are required by law to dispose of this waste wood – that includes leftover tree limbs and tops, and wood that is rotten, diseased and already fire damaged – to reduce the risks of wildfires and the spread of disease and pests.

The smoke from these fires is choking surrounding communities – sometimes “smoking out entire valleys,” air quality meteorologist from BC’s Environment Ministry Trina Orchard recently told iNFOnews.ca.

It also impacts the broader environment, releasing some 3 million tonnes of CO2 a year into the atmosphere, according to some early estimates.

Slash pile in British Columbia

Landfilling this waste material from logging operations isn’t an option as it would emit methane – a greenhouse gas that is about 25 times more potent than CO2. So you can see why it ends up being burned.

In its Modernizing Forest Policy in BC, the government has already identified its intention to phase out the burning of this waste wood left over after harvesting operations and is working with suppliers and other companies to encourage the use of this fibre.

This is a very positive move as this material must come out of the forests to reduce the fuel load that can help wildfires grow and spread to the point where they can’t be controlled, let alone be extinguished.

The wildfire risk is real and growing. Each year more forests and land are destroyed by wildfire, impacting communities, nature, wildlife and the environment.

In the past two decades, wildfires burned two and a half times more land in BC than in the previous 50-year period. According to very early estimates, emissions from last year’s wildfires in the province released around 150 million tonnes of CO2 – equivalent to around 30 million cars on the road for a year.

Alan Knight at the log yard for Lavington Pellet Mill in British Columbia

During my recent trip to British Columbia in Canada, First Nations, foresters, academics, scientists and government officials all talked about the burning piles of waste wood left over after logging operations.

Rather than burning it, it would be far better, they say, to use more of this potential resource as a feedstock for pellets that can be used to generate renewable energy, while supporting local jobs across the forestry sector and helping bolster the resilience of Canada’s forests against wildfire.

I like this approach because it brings pragmatism and common sense to the debate over Canada’s forests from the very people who know the most about the landscape around them.

Burning it at the roadside is a waste of a resource that could be put to much better use in generating renewable electricity, displacing fossil fuels, and it highlights the positive role the bioenergy industry can play in enhancing the forests and supporting communities.

Drax is already using some of this waste wood – which I saw in the log yard for our Lavington Pellet mill in British Columbia. This waste wood comprises around 20% of our feedstock. The remaining 80% comes from sawmill residues like sawdust, chips and shavings.

Waste wood for pellets at Lavington Pellet Mill log yard

It’s clear to me that using this waste material that has little other use or market value to make our pellets is an invaluable opportunity to deliver real benefits for communities, jobs and the environment while supporting a sustainable circular economy in the forestry sector.

What is renewable energy?

These differ to non-renewable energy sources such as coal, oil and natural gas, of which there is a finite amount available on Earth, meaning if used excessively they could eventually run out.

Renewable resources can provide energy for a variety of applications, including electricity generation, transportation and heating or cooling.

The difference between low-carbon, carbon neutral and renewable energy

Renewables such as wind, solar and hydropower are zero carbon sources of energy because they do not produce any carbon dioxide (CO2) when they generate power. Low-carbon sources might produce someCO2, but much less than fuels like coal.

Bioenergy that uses woody biomass from sustainably managed forests to generate electricity is carbon neutral because forests absorb CO2 from the atmosphere as they grow, meaning the amount of CO2 in the atmosphere remains level. Supply chains that bring bioenergy to power stations commonly use some fossil fuels in manufacturing and transportation. Therefore woody biomass is a low carbon fuel, when its whole lifecycle is considered.

Managing forests in a sustainable way that does not lead to deforestation allows bioenergy to serve as a renewable source of power. Responsible biomass sourcing also helps forests to absorb more carbon while displacing fossil fuel-based energy generation.

Nuclear is an example of a zero carbon source of electricity that is not renewable. It does not produce CO2,but it is dependent on uranium or plutonium, of which there is a finite amount available.

Managing forests in a sustainable way that does not lead to deforestation allows bioenergy to serve as a renewable source of power.

How much renewable energy is used around the world?

Humans have harnessed renewable energy for millions of years in the form of woody biomass to fuel fires, as well as wind to power ships and geothermal hot springs for bathing. Water wheels and windmills are other examples of humans utilising renewable resources, but since the industrial revolution fossil fuels, coal in particular, have been the main source of power.

However, as the effects of air pollution and CO2 produced from burning fossil fuels become increasingly apparent, renewable energy is gradually replacing sources which contribute to climate change.

In the year 2000 renewable energy accounted for 18% of global electricity generation, according to the IEA. By 2019, renewable sources made up 27% of the world’s electrical power.

Why renewable energy is essential to tackling climate change

The single biggest human contribution to climate change is greenhouse gas emissions, such as CO2, into the atmosphere. They create an insulating layer around the planet that causes temperatures on Earth to increase, making it less habitable.

Renewable sources of electricity can help to meet the world’s demand for power without contributing to global warming, unlike carbon-intensive fuels like coal, gas and oil.

Bioenergy can also be used to remove CO2 from the atmosphere while delivering renewable electricity through a process called bioenergy with carbon capture and storage (BECCS).

Forests absorb CO2 from the atmosphere, then when the biomass is used to generate electricity the same CO2 is captured and stored permanently underground – reducing the overall amount of CO2 in the atmosphere.

Humans have used renewable energy for millions for years, from wood for fires to wind powering boats to geothermal hot springs. 

What’s holding renewables back?

The world’s energy systems were built with fossil fuels in mind. This can make converting national grids difficult and installing new renewable energy sources expensive. However, as knowledge grows about how best to manufacture, build and operate renewable systems, the cost of deploying them at scale drops.

There are future changes needed. Renewables such as wind, solar and tidal power are known as intermittent renewables because they can’t generate electricity when there is no sun, wind or the tidal movement. For future energy systems to deliver enough power, large scale energy storage, as well as other flexible, reliable forms of generation will also be needed to meet demand and keep systems stable.

Renewable energy key facts:  

Go deeper

Turning waste into watts

Fields being ploughed by tractor

Think of carbon emissions and the image that comes to mind is often of industrial sites or power generation – not of what we eat and what we throw away. But food waste is a major contributor of greenhouse gas emissions.

Globally, food loss and waste from across the food chain generates the equivalent of 4.4 gigatonnes of carbon dioxide (CO2) a year, or about 8% of total greenhouse gas emissions.

But what if there was a way to reduce those emissions and generate power by using discarded food and other organic waste like grass cuttings or nut shells? A technology known as anaerobic digestion is increasingly making this idea a reality.

How anaerobic digestion works

All organic waste products have energy in them, but it’s tied up in the form of calories. When food and vegetation rots, microorganisms break down those calories into gases and other products.

Methane or Ammonium molecules. Science concept. 3D rendered illustration.

Methane or Ammonium molecules.

Exactly what these ‘other products’ are depends on whether there is any oxygen present. With oxygen, the products are water, CO2 and ammonia, but remove oxygen from the equation and a very valuable gas is produced: methane (CH4). The lack of oxygen is also what gives anaerobic digestion its name – when oxygen is present it becomes aerobic digestion.

During the anaerobic digestion process, bacteria and other microorganisms break down organic matter, gradually deteriorating complex polymers like glucose or starch into progressively simpler elements, such as alcohol, ammonia, CO2 and, ultimately, CH4, a biogas with huge potential as a fuel for other processes.

Anaerobic power in practice

The CH4 produced in anaerobic digestion is incredibly useful as a fuel – turn on a gas hob or stovetop and it’s predominantly methane that provides the fuel for the flame. The chemical compound is also the main component in the natural gas that makes up much of Great Britain’s electricity supply.

This means using anaerobic digestion to create CH4 out of waste products turns that waste into a valuable power source. But it’s not as simple as putting a bag over a rubbish tip and hoping for the best.

Instead, anaerobic digestion is carried out in large tanks called digesters. These are filled with feedstocks from biological substances that can include anything from food scraps, to alcohol and distillery waste, to manure. Under the right conditions microorganisms and bacteria begin to digest and breakdown these substances into their basic elements.

The air quantity and temperature of the digesters is carefully regulated to ensure the microorganisms have the best possible environment to carry out the digestion of the feedstock, with different types of feedstock and microorganisms operating best in different conditions.

The biogas created as a result of this digestion is then captured, ready to be turned into something useful.

biogas plant

Making use of biogas

Three different things can happen to the biogas produced during the course of the digestion. Locally, it can be combusted on-site to provide further heat to regulate the temperature of the anaerobic digestion units.

Or, it can be combusted in a combined heat and power (CHP) generator, where it can generate electricity to be used on site — for example to power a farm — or sold through energy suppliers such as Opus Energy onto wider regional or national electricity networks. This biogas electricity is an important element of Great Britain’s energy supply, accounting for 6,600 GWh or 7.3% of all power generated by solid and gaseous fuels in 2017.

Some of the biogas can even be cleaned to remove CO2, leaving behind pure methane that can be pumped onto natural gas grids and used to provide heat and power to households. Government research estimates a fully utilised biogas sector could provide up to 30% of the UK’s household gas demands.

After the digestion process has been completed and the biogas has been removed, what is left behind in the digester is a mass of solid matter called digestate. This is extremely rich in nutrients and mineral, such as potassium and nitrogen, making it an excellent soil enhancer.

Where anaerobic digestion is being used today

Today, much of anaerobic digestion power is generated on farms – unsurprisingly, given the ready access to biological waste material to use as feedstock. As well as a potential source of electricity and heat, it also gives farmers access to a new revenue stream, by selling electricity or biogas, as well as reducing utility and fertiliser costs.

While many of these installations are smaller scale, some can get quite big. Linstock Castle Farm in North Cumbria, for example, has a biogas facility with a 1.1 megawatt(MW) operating capacity, enough to power as many as 2,000 homes at a time. It was originally installed by the farmers as a more cost-effective way of growing their business than buying more dairy cows.

Biogas plant on a farm processing cow dung as a secondary business activity

There is, however, potential for anaerobic digestion to operate on an even larger scale. In the US, the city of Philadelphia is developing a system that will link all newly built households together into a network where food waste is automatically collected and transported to a biogas generating facility.

Closer to home, Northumbrian Water uses 100% of its sludge, the waste produced from purifying water, to produce renewable power via anaerobic digestion. It’s estimated to have reduced the carbon footprint of the facility’s operations by around 20%, and saved millions of pounds in savings on operating costs.

There have also been experiments with using biogas to power vehicles. The ‘Bio-Bus’ was the first bus in the UK to be powered by biomethane made from food, sewage and commercial liquid waste, and ran between Bath and Bristol Airport.

But anaerobic digestion power is not a magic bullet. It will be right in certain situations, but not all. If utilised effectively, anaerobic digestion and biogas could fill a vital role in national electricity and gas networks, while at the same time helping dispose of waste products in an environmentally-friendly and cost-effective way.

Why spin a turbine without generating power?

Turbine at Cruachan Power Station

Massive spinning machinery is a big part of electricity generation whether it’s a wind turbine, hydro plant or biomass generator.

But big spinning turbines don’t just pump electricity out onto the grid. They also play a crucial role in keeping the electricity system stable, safe and efficient. This is because big, heavy spinning turbines add something else to the grid: inertia.

This is defined as an object’s resistance to change but in the context of electricity it helps the grid remain at the right frequency and voltage level. In short, they help the grid remain stable.

However, as electricity systems in Great Britain and other parts of the world move away from coal and gas to renewables, such as wind turbines, solar panels and interconnectors, the level of inertia on the system is falling.

“We need the inertia, we don’t need the megawatts,” explains Julian Leslie, Head of Networks at the National Grid Electricity System Operator (ESO). “But in today’s market we have to supply the megawatts and receive the inertia as a consequence.”

Turbine at Drax Power Station

Engineer inspecting turbine blades at Drax Power Station

The National Grid ESO is taking a new approach to this aspect of grid stability by using what are called synchronous condensers. These complicated-sounding pieces of machinery are actually quite straightforward in their concept: they provide inertia to the grid without generating unnecessary power.

These come in the form of:

  • Existing generators that remain connected to the grid but refrain from producing electricity.
  • Purpose built machines whose only function is to act as synchronous condensers, never generating real power. These may be fitted with flywheels to increase their mass and, in consequence, their inertia.

This means that spinning without generating is about to become a very important part of Great Britain’s electricity system.

Around and around

Electricity generators that spin at 3,000 rpm are described as synchronous generators because they are in sync with the grid’s frequency of 50Hz. These include coal, gas, hydro, biomass turbines and nuclear units. Most spin at 3000 rpm, some machines much less (e.g. 750 rpm). Thanks to the way they are designed, they are all synchronised together at the same, higher speed.

Then there are wind turbines where the generated power is not synchronised to the grid system. Termed asynchronous generators, these machines do not have readily accessible stored energy (inertia) and do not contribute to the stability of the system. Interconnectors and solar panels are also asynchronous.

It’s important that Great Britain’s whole grid is kept within 1% of the 50Hz frequency, otherwise the voltage of electricity starts to fluctuate, damaging equipment, becoming less efficient, even dangerous, or resulting in blackouts.

Say a power station or a wind farm were to drop offline, as occurred in August 2019, this would cause the amount of power on the grid to suddenly fall. But it is not just the power that changes – the frequency and voltage also fluctuate dramatically which can cause equipment damage and ultimately, towns, cities or widespread areas to lose power.

Running machines that have inertia act like the suspension on a car – they dampen those fluctuations, so they are not as drastic. The big spinning machines keep spinning, buying valuable milliseconds for the grid to react, often automatically, before the damage becomes widespread.

However, as a consequence of decarbonisation, more solar panels and wind turbines are now on the system and there are fewer spinning turbines, leading to lower levels of inertia on the grid.

“There are periods when renewable generation and flow from interconnectors are so great that it displaces all conventional, rotational power plants,” says Leslie. “Today, bringing more inertia onto the grid may mean switching off renewables or interconnectors, and then replacing them with rotating plants and the megawatts associated with that.”

Creating a market for inertia and synchronous condensers offers a new way forward – providing inertia without unneeded megawatts or emissions from fossil fuels.

A new spin on grid stability

At the start of 2020, The National Grid ESO began contracting parties, including Drax’s Cruachan pumped-hydro power station, to operate synchronous condensers and provide inertia to the grid when needed.

The plans mark a departure from the previous system where inertia and voltage control from electricity generators was taken for granted.

Cruachan Power Station is already capable of running its units in synchronous condenser mode (one of its units, opened up for maintenance, is pictured at the top of this article). This involves an alternator acting as a motor, offering inertia to the grid without generating unneeded electricity. Other service providers will repurpose existing turbines, construct new machines or develop new technologies that can electronically respond to the grid’s need for stability.

Synchronous condensers, or the idea of spinning a turbine freely without generating power, are not new concepts; power stations in the second half of the 20th century could shut down certain generating units but keep them spinning online for voltage control.

In the 1960s and 70s, some substations – where the voltage of electricity is stepped up and down from the transmission system – also deployed stand-alone synchronous condensers. These were also used to provided inertia as well as voltage control but are long since decommissioned.

Synchronous condenser installation at Templestowe substation, Melbourne Victoria, Australia. By Mriya via Wikimedia.

“Synchronous condensers are a proven technology that have been used in the past,” says Leslie. “And there are many new technologies we are now exploring that can deliver a similar service.”

Cheaper, cleaner, more stable

Commercial UK wind turbines

The National Grid ESO estimates the technology will save electricity consumers up to £128 million over the next six years. Savings, which come from negating the need for the grid to call upon fossil fuels for inertia as coal, oil and gas, become increasingly uneconomical across the globe as carbon taxes grow.

The fact that synchronous condensers do not produce electricity also saves money the grid may have had to pay out to renewable generators to stop them producing electricity or to storage systems to absorb excess power.

“It means the market can deliver the renewable flow without the grid having to pay to restrain it or to pay for gas to stabilise the system,” says Leslie. “Not only does this allow more renewable generation, but it also reduces the cost to the consumer.”

In a future energy system, where there is an abundance of renewable electricity generations, synchronous condensers will be crucial in keeping the grid stable. The National Grid ESO’s investment in the technology further highlights the importance of new ideas and innovation to balance the grid through this energy transition.

Synchronous generation provides benefits to system stability beyond the provision of inertia. In a subsequent article we’ll also explore how synchronous condensers can assist with voltage stability and help regional electricity networks and customers to remain connected to the national system during and after faults.

Read about the past, present and future of the country’s electricity system in Could Great Britain go off grid? 

Where does global electricity go next?

Since the Paris Agreement came into effect in November 2016, it’s fair to say many countries have taken up the vital challenge of decarbonisation in earnest.

However, not all are making progress at the same rate. Many are not implementing the agreement at the pace needed to mitigate climate change, and keep the average global temperature increase well below 2oC of pre-industrial levels. Certainly not enough to limit the increase to 1.5oC by 2050, which the majority of climate scientists believe is necessary for the planet is to avoid dire consequences.

Last year even saw renewable energy investment fall 7%, while the money going into fossil fuels grew for the first time since 2014. And data released by the International Energy Agency (IEA) at the beginning of this month’s UN Climate Change Conference (COP24) in Katowice, Poland, found that 2017 was also the first for five years seeing an increase in advanced economies’ carbon emissions.

Despite this, there is much positive work towards decarbonisation.

A new report, Energy Revolution: A Global Outlook, by academics from Imperial College London and E4tech, commissioned by Drax, looks into the core areas and activities required to decarbonise the global energy system – and which countries are performing them to good effect. In doing this, the report also looks at how the UK stands in comparison and what steps countries need to take to truly decarbonise.

Here are the key indicators of decarbonisation and how countries around the world are performing towards them.

Dam in Hardangervidda, Norway

Clean power

At the forefront of reducing emissions and curbing climate change is the need to decarbonise electricity generation and move towards renewable sources.

Last year the global average carbon intensity was 440 grams of carbon dioxide (CO2) per kilowatt-hour (g/kWh). Out of the 25 major countries the report tracks, 16 came in below average, with seven of these falling under the long-term 50 g/kWh goal.

Leading the rankings are Norway, France and New Zealand, which have a near-zero carbon intensity for electricity generation, thanks to extensive hydro and nuclear power capacity.

At the other end of the table, China, India, Poland and South Africa remain wedded to coal, producing up to twice the global average CO2 for electricity generation. This comes despite China having installed two and a half times more renewables than any other country – it now boasts 600 gigawatts (GW) of renewable capacity.

Per person, Germany is leading the renewablesdrive with almost 1 kW of wind and solar capacity installed per person over the last decade. Despite this, as much as 40% of its electricity still comes from coal.

Part of the challenge in moving away from coal to renewables is economic, as many countries continue to subsidise their coal industries to keep electricity affordable. Phasing out these subsidies is therefore key to switching to a low-carbon generation system. Doing this works, as demonstrated by the example of Denmark, which cut its fossil fuel subsidies by 90% over the past decade, in turn successfully cutting its coal generation by 25%.

The UK’s carbon pricing strategy, which adds £16 per tonne of CO2emitted on top of the price set by the European emissions trading system (EU ETS), has led the carbon intensity of Great Britain’s electricity to more than halve in a decade. It highlights how quickly and effectively these kinds of fees can make fossil fuels uneconomical. Since 2008 the UK has removed more than 250 g/kWh from its electricity production.

Carbon capture and storage

In many future looking climate scenarios, keeping the earth’s temperature below a 2oC increase depends on extensive deployment of carbon capture technology – capturing as much as 100 billion tonnes of CO2 per year. Storing and using carbon is clearly forecast to be a major part of any attempt to meet the Paris Agreement, but at present there are few facilities carrying it out at scale.

Around the world today there are 18 large-scale carbon capture and storage (CCS) units running across six countries with a total capacity to capture 32 million tonnes of CO2 per year (MtCO2p.a). Another five facilities are under construction in three countries to add another 7 MtCO2p.a of global capacity. In the UK, Drax Power Station is piloting a bioenergy carbon capture and storage programme that could make it the world’s first negative emissions power station.

The USA has the greatest total installed capacity at 20 MtCO2p.a., but per person it ranks behind Norway, Canada and Australia. Their smaller populations give them more than 200 kg of carbon capture capacity per person per year.

Oil platform off the coast of Australia

These figures are well below the 100 billion tonnes the IEA estimates need to be stored by 2060 to prevent temperatures reaching 2oC more. However, considering the US alone has a potential storage capacity of more than 10 trillion tonnes of CO2, the potential of storage is not expected to be a problem.

Using depleted oil or natural gas fields as storage for captured carbon is being explored in a number of regions, with the US establishing several projects with more than 1 million tonnes in capacity. In 2019, Australia will open the world’s largest CO2store with the capacity to capture between 3.4 million and 4 million tonnes a year from Chevron’s Gorgon gas facility.

Considering the storage capacity available globally, it’s a matter of deploying the necessary technology for CCS to have a significant impact on emissions and global warming. The UK is perhaps a typical example of where CCS is at present with estimated storage capacity of 70 billion tonnes, as much as half of the entire EU combined. By repurposing North Sea oil and gas fields in partnership with Norway, the UK could pool its carbon storage capacity.

Electrification

Electricity generation is one of the main targets for emissions reductions globally. As a result of the progress that’s been made in this field, many future-looking scenarios highlight the important of electrification in other sectors, such as transport, in turn making them less carbon intensive.

Transport is leading the charge globally – there are now 10 different countries where one of every 50 new vehicles sold is electric. In Norway, this ratio is almost one in two, thanks in part to generous tax exemptions as well as non-financial incentives like access to bus lanes and half-price ferries.

Perhaps surprisingly, China is the world’s largest electric vehicle (EV) market. It may still use significant amounts of coal, but its commitment to reducing urban air pollution has seen it push EVs heavily, and it now accounts for 50% of the global battery EV market on its own.

Chinese electric car charging stations

Of course, adoption of EVs requires the supporting infrastructure to be truly successful. In conjunction with its high sales, Norway leads the way in charging points per capita, with one for every 500 people. This compares to one charger for every 5,000 people in the UK and one for every 10,000 people in China.

Electrification also affects the energy intensity of country’s transport systems and while it may be the largest EV market, China’s rise in private vehicles has been largely driven by petrol and diesel models. The result is the largest increases in transport energy intensity and emissions has taken place in China, Indonesia and India, respectively.

Domestic energy intensity is also rising in China, Indonesia and South Africa, as greater numbers of people gain access to appliances and home comforts. Conversely in Europe, Portugal, Germany and the Netherlands have all seen their domestic energy intensity drop in the last decade. However, this may be the lingering effect of the 2008 recession rather than long-term efficiency improvements.

The efficiency of industrial processes is also an important barometer in decarbonisation. Activities like mining and manufacturing require heavy-duty diesel-powered machinery and often coal-powered generators, especially in BRIC nations. The exception is China, where plans to get the 1,000 most energy-intensive companies to reduce their energy consumption per unit of GDP produced by 20% over the last five years, has proved fruitful.

Norway’s heavily-electrified industries, however, are still energy intensive and its level of carbon intensity is vulnerable to fluctuations in power generation prices.

Electrification and reduced emissions require government policies to put in motion behavioural changes that can lead to lasting decarbonisation. Robust carbon pricing is one of the most effective tools to enabling a zero carbon, lower cost energy future,” Drax Group CEO Will Gardiner commented recently.

Welcoming a November report by the Energy Transitions Commission, Gardiner said:

“The cost of inaction far outweighs the cost of doing something now.”

Explore the full report: Energy Revolution: A Global Outlook.

I. Staffell, M. Jansen, A. Chase, E. Cotton and C. Lewis (2018). Energy Revolution: Global Outlook. Drax: Selby.

Drax commissioned independent researchers from Imperial College London and E4tech to write Energy Revolution: A Global Outlook, which looks into the core areas and activities required to achieve decarbonisation – and which countries are performing them to good effect. In doing this it also looks at how the UK stands in comparison and what steps countries need to take to truly decarbonise.

The 8 biggest things in renewable energy

Powering a whole country is a big task. The equipment that make up power stations and electricity systems are measured in tonnes and miles, and pump gigawatts (GW) of electricity around the country. With the world’s electricity increasingly coming from renewables, this big thinking is key to powering long-term change.

From taller wind turbines to bigger batteries, these are the massive structures breaking energy records.

Germany’s giant wind turbine and the plan to beat it

As wind power becomes ever more prevalent, one of the key questions that needs answering is how to get more out of it. One way is to build taller turbines and longer blades. Putting turbines higher into the air sets them into stronger wind flows, while longer blades increase their generating capacity.

The world’s tallest wind turbines are currently in Gaildorf, Germany and stand at 178 metres with the blades tips reaching 246.5 metres. Built by Max Bögl Wind AG, the onshore turbines house a 3.4 megawatt (MW) generator that can produce around 10.5 gigawatt hours (GWh) per year.

However, turbines continue to grow and GE has announced plans for the Haliade-X turbine, which will ship in 2021. At 259 metres in total the offshore turbine is almost double the height of the London Eye and will spin 106 metre blades, generating 67 GWh per year.

China’s ‘Great Wall of Solar’

China has pumped substantial investment into solar power, including the world’s biggest solar plant in electricity generation and sheer size. Dubbed the ‘Great Wall of Solar’, the Tengger Desert Solar Park has a capacity of more than 1.5 GW and covers 43 km2 of desert.

The next largest, by comparison, is India’s Kurnool Ultra Mega Solar Park, which covers just 24 km2 and generates 1 GW. However, rampant investment by the country means there are several projects in the pipeline that will break the 2 GW mark and will set new records for solar power plants.

Morocco takes solar to new heights

Concentrated solar power (CSP) takes the technology skywards by using thousands of mirrors, known as heliostats, and focusing the sun’s rays towards a central tower. This heats up molten salt within the tower, which is then combined with water to create steam and power a turbine – like in a thermal power plant.

Morocco’s Noor Ouarzazate facility (pictured in the main photo of this article) is home to the world’s tallest CSP towers. At 250 metres tall, 7,400 heliostats beam the sunlight at each tower, which have a capacity of 150 MW and can store molten salt for 7.5 hours. Its record will soon be matched by Israel’s 121 MW Ashalim Solar Thermal Power Station when it begins operating this year.

However, never one to be outdone when it comes to tall structures, Dubai plans to build a 260 metre CSP tower in 2020 as part of the Mohammed bin Rashid Al Maktoum Solar Park, which at 700 MW will be the world’s largest single-site CSP facility.

Three Gorges Dam

China’s monster mountain dam

The Three Gorges Dam on China’s Yangtza river might be the world’s most powerful hydropower dam with its massive 22.5 GW capacity, but a different Chinese dam holds the title of the world’s tallest.

Jinping-I Hydropower Station is a 305-metre-tall arch dam on the Yalong River. It sits on the Jinping Bend where the river wraps around the entire Jinping mountain range. The project began in 2005 and was completed with the commissioning of a sixth and final generator in 2014, which brought its total capacity to 3.6 GW.

Itaipu Dam and hydropower station

Brazil and Paraguay’s river arrangement

While it may be tall, at 568 metres-long, Jinping-I is far from the longest. That mantle belongs to the 7,919 metre-long Itaipu Dam and hydropower station that straddles Brazil and Paraguay and has an installed capacity of 14 GW.

The power station is home to 20, 700 MW generators, however, as Brazil’s electricity system runs at 60Hz and Paraguay’s at 50Hz, 10 of the generators run at each frequency.

Biomass domes that could hide the Albert Hall

Using a relatively new material, such as compressed wood pellets as a renewable alternative to coal in large thermal power stations creates new challenges. Biomass ‘ecostore’ domes help tackle storage problems by keeping the materials dry and maintaining the right temperatures and conditions.

Unlike cylindrical, concrete silos, domes also offer greater resistance to hurricanes and extreme weather. This is important in areas such as Louisiana where this low carbon fuel  is stored at the Drax Biomass port facility in 35.7 metre high, 61.6 metre diameter domes before it is shipped to Drax Power Station.

The power station itself is home to four of the world’s largest biomass domes. Each is 50.3 metres high and 63 metres in diameter – enough to hold the Albert Hall, or in Drax’s case 71,000 tonnes of biomass.

South Korean coastline takes the most from the tides

Beginning operation 1966, the Rance Tidal Power Station, in France was the first and largest facility of its kind for 45 years. The power station made use of the 750 metre-long Rance Barrage on France’s northern coast with a 330-metre-long section of it generating electricity through 24, 10 MW turbines.

It was overtaken, however, in 2011 with the opening of the Sihwa Lake Tidal Power Station in South Korea. The facility generates power along a 400-metre section of the 12.7 km Sihwa Lake tidal barrage and generates a maximum of 254 MW through ten 25.4 MW submerged turbines.

The battle to beat Tesla’s giant battery

South Australia has become a battlefield in the race to build the world’s biggest grid scale storage solution. Tesla constructed a 10,000 m2, football pitch-sized 100 MW lithium-ion battery outside of Adelaide at the end of 2017 which is connected to a wind power plant and can independently supply electricity to 30,000 homes for an hour.

However, rival billionaire to Tesla’s Elon Musk, Sanjeev Gupta plans to take on the storage facility with a 140 MW battery to support a new solar-powered steelworks, also in South Australia.

The excitement around battery technology’s potential means the title of world’s biggest will likely swap hands plenty more times over the next decade. This contest won’t just be confined to batteries. As countries increasingly move away from fossil fuels, bigger, wider and taller renewable structures will be needed to power the world. These are the world’s largest renewable structures today, but they probably won’t stay in those positions for long.