Tag: hydrogen

How biomass can enable a hydrogen economy

10 March 2022

Carbon capture

Key points:

  • Hydrogen as a fuel offers a carbon-free alternative for hard-to-abate sectors such as heavy road transport, domestic heating, and industries like steel and cement.
  • There are several methods of producing hydrogen, the most common being steam methane reforming, which can be a carbon-intensive process.
  • Biomass gasification with CCS is a form of bioenergy with carbon capture and storage (BECCS) that can produce hydrogen and negative emissions – removing CO2 permanently from the atmosphere.
  • The development of both BECCS and hydrogen technologies will determine how intrinsically connected the two are in a net zero future.

Reaching net zero means more than just transitioning to renewable and low carbon electricity generation. The whole UK economy must transform where its energy comes from to low-emissions sources. This includes ‘hard-to-abate’ industries like steel, cement, and heavy goods vehicles (HGVs), as well as areas such as domestic heating

One solution is hydrogen. The ultra-light element can be used as a fuel that when combusted in air produces only heat, water vapour, and nitrous oxide. As hydrogen is a carbon-free fuel, a so-called ‘hydrogen economy’ has the potential to decarbonise hard-to-abate sectors.

While hydrogen is a zero-carbon fuel its production methods can be carbon-intensive. For a hydrogen economy to operate within a net zero UK carbon-neutral means of producing it are needed at scale. And biomass, energy from organic material – with or without carbon capture and storage (in the case of BECCS)– could have a key role to play.

In January 2022, the UK government launched a £5 million Hydrogen BECCS Innovation Programme. It aims to develop technologies that can both produce hydrogen for hard-to-decarbonise sectors and removeCO2 from the atmosphere. The initiative highlights the connected role that biomass and hydrogen can have in supporting a net zero UK.

Producing hydrogen at scale

Hydrogen is the lightest and most abundant element in the universe. However, it rarely exists on its own. It’s more commonly found alongside oxygen in the familiar form of H2O. Because of its tendency to form tight bonds with other elements, pure streams of hydrogen must be manufactured rather than extracted from a well, like oil or natural gas.

As much as 70 million tonnes of hydrogen is produced each year around the world, mainly to make ammonia fertiliser and chemicals such as methanol, or to remove impurities during oil refining. Of that hydrogen, 96% is made from fossil fuels, primarily natural gas, through a process called steam methane reforming, of which hydrogen and CO2 are products. Without the use of carbon capture, utilisation, and storage (CCUS) technologies the CO2 is released into the atmosphere, where it acts as a greenhouse gas and contributes to climate change.

Another method of producing hydrogen is electrolysis. This process uses an electric current to break water down into hydrogen and oxygen molecules. Like charging an electric vehicle, this method is only low carbon if the electricity sources powering it are as well.

For electrolysis to support hydrogen production at scale depends on a net zero electricity grid built around renewable electricity sources such as wind, solar, hydro, and biomass.

However, bioenergy with carbon capture and storage (BECCS) offers another means of producing carbon-free renewable hydrogen, while also removing emissions from the atmosphere and storing it – permanently.

Producing hydrogen and negative emissions with biomass 

Biomass gasification is the process of subjecting biomass (or any organic matter) to high temperatures but with a limited amount of oxygen added that prevents complete combustion from occurring.

The process breaks the biomass down into a gaseous mixture known as syngas, which can be used as an alternative to methane-based natural gas in heating and electricity generation or used to make fuels. Through a water-gas shift reaction, the syngas can be converted into pure streams of CO2 and hydrogen.

Ordinarily, the hydrogen could be utilised while the CO2 is released. In a BECCS process, however, the CO2 is captured and stored safely and permanently. The result is negative emissions.

Here’s how it works: BECCS starts with biomass from sustainably managed forests. Wood that is not suitable for uses like furniture or construction – or wood chips and residues from these industries – is often considered waste. In some cases, it’s simply burnt to dispose of it. However, this low-grade wood can be used for energy generation as biomass.

When biomass is used in a process like gasification, the CO2 that was absorbed by trees as they grew and subsequently stored in the wood is released. However, in a BECCS process, the CO2 is captured and transported to locations where it can be stored permanently.

The overall process removes CO2 from the atmosphere while producing hydrogen. Negative emissions technologies like BECCS are considered essential for the UK and the world to reach net zero and tackle climate change.

Building a collaborative net zero economy  

How big a role hydrogen will play in the future is still uncertain. The Climate Change Committee’s (CCC) 2018 report ‘Hydrogen in a low carbon economy’ outlines four scenarios. These range from hydrogen production in 2050 being able to provide less than 100 terawatt hours (TWh) of energy a year to more than 700 TWh.

Similarly, how important biomass is to the production of hydrogen varies across different scenarios. The CCC’s report puts the amount of hydrogen produced in 2050 via BECCS between 50 TWh in some scenarios to almost 300 TWh in others. This range depends on factors such as the technology readiness level of biomass gasification. If it can be proven – technical work Drax is currently undertaking – and at scale, then BECCS can deliver on the high-end forecast of hydrogen production.

The volumes will also depend on the UK’s commitment to BECCS and sustainable biomass. The CCC’s ‘Biomass in a low carbon economy’ report offers a ‘UK BECCS hub’ scenario in which the UK accesses a greater proportion of the global biomass resource than countries with less developed carbon capture and storage systems, as part of a wider international effort to sequester and store CO2. The scenario assumes that the UK builds on its current status and continues to be a global leader in BECCS supply chains, infrastructure, and geological storage capacity. If this can be achieved, biomass and BECCS could be an intrinsic part of a hydrogen economy.

There are still developments being made in hydrogen and BECCS, which will determine how connected each is to the other and to a net zero UK. This includes the feasibility of converting HGVs and other gas systems to hydrogen, as well as the efficiency of carbon capture, transport and storage systems. The cost of producing hydrogen and carrying out BECCS are also yet to be determined.

The right government policies and incentives that encourage investment and protect jobs are needed to progress the dual development of BECCS and hydrogen. Success in both fields can unlock a collaborative net zero economy that delivers a carbon-free fuel source in hydrogen and negative emissions through BECCS.

Committing to a net zero power system as part of COP26

30 November 2020

Carbon capture

Dear Prime Minister, Chancellor, COP26 President and Minister for Energy and Clean Growth,

We are a group of energy companies investing tens of billions in the coming decade, deploying the low carbon infrastructure the UK will need to get to net zero and drive a green recovery to the COVID-19 crisis.

We welcome the leadership shown on the Ten Point Plan for a Green Industrial Revolution, and the detailed work going on across government to deliver a net zero economy by 2050. We are writing to you to call on the Government to signal what this will mean for UK electricity decarbonisation by committing to a date for a net zero power system.

Head of BECCS inspects pilot plant within Drax Power Station's CCUS Incubation Unit

Head of BECCS Carl Clayton inspects pipes at the CCUS Incubation Area, Drax Power Station

The electricity sector will be the backbone of our net zero economy, and there will be ever increasing periods where Great Britain is powered by only zero carbon generation. To support this, the Electricity System Operator is putting in place the systems, products and services to enable periods of zero emissions electricity system operation by 2025.

Achieving a net zero power system will require government to continue its efforts in key policy areas such as carbon pricing, which has been central in delivering UK leadership in the move away from coal and has led to UK electricity emissions falling by over 63% between 2012 and 2019 alone.

It is thanks to successive governments’ commitment to robust carbon pricing that the UK is now using levels of coal in power generation last seen 250 years ago – before the birth of the steam locomotive. A consistent, robust carbon price has also unlocked long term investment low-carbon power generation such that power generated by renewables overtook fossil fuel power generation for the first time in British history in the first quarter of 2020.

Yet, even with the demise of coal and the progress in offshore wind, more needs to be done to drive the remaining emissions from electricity as its use is extended across the economy.

In the near-term, in combination with other policies, continued robust carbon pricing on electricity will incentivise the continued deployment of low carbon generation, market dispatch of upcoming gas-fired generation with Carbon Capture and Storage (CCS) projects and the blending of low carbon hydrogen with gas-fired generation. Further forward, a robust carbon price can incentivise 100% hydrogen use in gas-fired generation, and importantly drive negative emissions to facilitate the delivery of a net zero economy.

Next year, the world’s attention will focus on Glasgow and negotiations crucial to achieving our climate change targets, with important commitments already made by China, the EU, Japan and South Korea amongst others. An ambitious 2030 target from the UK will help kickstart the Sprint to Glasgow ahead of the UK-UN Climate Summit on 12 December.

Electricity cables and pylon snaking around a mountain near Cruachan Power Station in the Highlands

Electricity cables and pylon snaking around a mountain near Cruachan Power Station, Drax’s flexible pumped storage facility in the Highlands

2030 ambition is clearly needed, but to deliver on net zero, deep decarbonisation will be required. Previous commitments from the UK on its coal phase out and being the first major economy to adopt a net zero target continue to encourage similar international actions. To build on these and continue UK leadership on electricity sector decarbonisation, we call on the UK to commit to a date for a net zero power system ahead of COP26, to match the commitment of the US President-elect’s Clean Energy Plan. To ensure the maximum benefit at lowest cost, the chosen date should be informed by analysis and consider broad stakeholder input.

Alongside near-term stability as the UK’s carbon pricing future is determined, to meet this commitment Government should launch a consultation on a date for a net zero power system by the Budget next year, with a target date to be confirmed in the UK’s upcoming Net Zero Strategy. This commitment would send a signal to the rest of the world that the UK intends to maintain its leadership position on climate and to build a greener, more resilient economy.

To:

  • Rt Hon Boris Johnson MP, Prime Minister of the United Kingdom
  • Rt Hon Rishi Sunak MP, Chancellor of the Exchequer
  • Rt Hon Alok Sharma MP, Secretary of State for Business, Energy and Industrial Strategy and UNFCCC COP26 President
  • Rt Hon Kwasi Kwarteng MP, Minister for Business, Energy and Clean Growth

Signatories:

BP, Drax, National Grid ESO, Sembcorp, Shell and SSE

View/download letter in PDF format

 

Could hydrogen power stations offer flexible electricity for a net zero future?

26 August 2020

Power generation
Pipework in a chemical factory

We’re familiar with using natural gas every day in heating homes, powering boilers and igniting stove tops. But this same natural gas – predominantly methane – is also one of the most important sources of electricity to the UK. In 2019 gas generation accounted for 39% of Great Britain’s electricity mix. But that could soon be changing.

Hydrogen, the super simple, super light element, can be a zero-carbon emissions source of fuel. While we’re used to seeing it in everyday in water (H2O), as a gas it has been tested as an alternative to methane in homes and as a fuel for vehicles.

Could it also replace natural gas in power stations and help keep the lights on?

The need for a new gas

Car arriving at hydrogen gas station

Hydrogen fuel station

Natural gas has been the largest single source of electricity in Great Britain since around 2000 (aside from the period 2012-14 when coal made a resurgence due to high gas prices). The dominance of gas over coal is in part thanks to the abundant supply of it in the North Sea. Along with carbon pricing, domestic supply makes gas much cheaper than coal, and much cleaner, emitting as much as 60% less CO2 than the solid fossil fuel.

Added to this is the ability of gas power stations to start up, change their output and shut down very quickly to meet sudden shifts in electricity demand. This flexibility is helpful to support the growth of weather-dependant renewable sources of power such as wind or solar. The stability gas brings has helped the country decarbonise its power supply rapidly.

Hydrogen, on the other hand, can be an even cleaner fuel as it only releases water vapour and nitrous oxide when combusted in large gas turbines. This means it could offer a low- or zero-carbon, flexible alternative to natural gas that makes use of Great Britain’s existing gas infrastructure. But it’s not as simple as just switching fuels.

Switching gases

Some thermal power stations work by combusting a fuel, such as biomass or coal, in a boiler to generate intense heat that turns water into high-pressure steam which then spins a turbine. Gas turbines, however, are different.

Engineer works on a turbine at Drax Power Station

Instead of heating water into steam, a simple gas turbine blasts a mix of gas, plus air from the surrounding atmosphere, at high pressure into a combustion chamber, where a chemical reaction takes place – oxygen from the air continuously feeding a gas-powered flame. The high-pressure and hot gasses then spin a turbine. The reaction that takes place inside the combustion chamber is dependent on the chemical mix that enters it.

“Natural gas turbines have been tailored and optimised for their working conditions,” explains Richard Armstrong, Drax Lead Engineer.

“Hydrogen is a gas that burns in the same way as natural gas, but it burns at different temperatures, at different speeds and it requires different ratios of oxygen to get the most efficient combustion.”

Switching a power station from natural gas to hydrogen would take significant testing and refining to optimise every aspect of the process and ensure everything is safe. This would no doubt continue over years, subtly developing the engines over time to improve efficiency in a similar way to how natural gas combustion has evolved. But it’s certainly possible.

What may be trickier though is providing the supply of hydrogen necessary to power and balance the country’s electricity system. 

Making hydrogen

Hydrogen is the most abundant element in the universe. But it’s very rare to find it on its own. Because it’s so atomically simple, it’s highly reactive and almost always found naturally bonded to other elements.

Water is the prime example: it’s made up of two hydrogen atoms and one oxygen atom, making it H2O. Hydrogen’s tendency to bond with everything means a pure stream of it, as would be needed in a power station, has to be produced rather than extracted from underground like natural gas.

Hydrogen as a gas at standard temperature and pressure is known by the symbol H2.

A power station would also need a lot more hydrogen than natural gas. By volume it would take three times as much hydrogen to produce the same amount of energy as would be needed with natural gas. However, because it is so light the hydrogen would still have a lower mass.

“A very large supply of hydrogen would be needed, which doesn’t exist in the UK at the moment,” says Rachel Grima, Research & Innovation Engineer at Drax. “So, at the same time as converting a power plant to hydrogen, you’d need to build a facility to produce it alongside it.”

One of the most established ways to produce hydrogen is through a process known as steam methane reforming. This applies high temperatures and pressure to natural gas to break down the methane (which makes up the majority of natural gas) into hydrogen and carbon dioxide (CO2).

The obvious problem with the process is it still emits CO2, meaning carbon capture and storage (CCS) systems are needed if it is to be carbon neutral.

“It’s almost like capturing the CO2 from natural gas before its combusted, rather than post-combustion,” explains Grima. “One of the advantages of this is that the CO2 is at a much higher concentration, which makes it much easier to capture than in flue gas when it is diluted with a lot of nitrogen.”

Using natural gas in the process produces what’s known as ‘grey hydrogen’, adding carbon capture to make the process carbon neutral is known as ‘blue hydrogen’ – but there are ways to make it with renewable energy sources too.

Electrolysis is already an established technology, where an electrical current is used to break water down into hydrogen and oxygen. This ‘green hydrogen’ cuts out the CO2 emissions that come from using natural gas. However, like charging an electric vehicle, the process is only carbon-neutral if the electricity powering it comes from zero carbon sources, such as nuclear, wind and solar.

It’s also possible to produce hydrogen from biomass. By putting biomass under high temperatures and adding a limited amount of oxygen (to prevent the biomass combusting) the biomass can be gasified, meaning it is turned into a mix of hydrogen and CO2. By using a sustainable biomass supply chain where forests absorb the equivalent of the CO2 emitted but where some fossil fuels are used within the supply chain, the process becomes low carbon.

Carbon capture use and storage (CCUS) Incubation Area, Drax Power Station

Carbon capture use and storage (CCUS) Incubation Area, Drax Power Station

CCS can then be added to make it carbon negative overall, meaning more CO2 is captured and stored at forest level and in below-ground carbon storage than is emitted throughout its lifecycle. This form of ‘green hydrogen’ is known as bioenergy with carbon capture and storage (BECCS) hydrogen or negative emissions hydrogen.

There are plenty of options for making hydrogen, but doing it at the scale needed for power generation and ensuring it’s an affordable fuel is the real challenge. Then there is the issue of transporting and working with hydrogen.

“The difficulty is less in converting the UK’s gas power stations and turbines themselves. That’s a hurdle but most turbine manufacturers already in the process of developing solutions for this,” says Armstrong.

“The challenge is establishing a stable and consistent supply of hydrogen and the transmission network to get it to site.”

Working with the lightest known element

Today hydrogen is mainly transported by truck as either a gas or cooled down to minus-253 degrees Celsius, at which point it becomes a liquid (LH2). However, there is plenty of infrastructure already in place around the UK that could make transporting hydrogen significantly more efficient.

“The UK has a very advanced and comprehensive gas grid. A conversion to hydrogen would be more economic if you could repurpose the existing gas infrastructure,” says Hannah Steedman, Innovation Engineer at Drax.

“The most feasible way to feed a power station is through pipelines and a lot of work is underway to determine if the current natural gas network could be used for hydrogen.”

Gas stove

Hydrogen is different to natural gas in that it is a very small and highly reactive molecule,  therefore it needs to be treated differently. For example, parts of the existing gas network are made of steel, a metal which hydrogen reacts with, causing what’s known as hydrogen embrittlement, which can lead to cracks and failures that could potentially allow gas to escape. There are also factors around safety and efficiency to consider.

Like natural gas, hydrogen is also odourless, meaning it would need to have an odourant added to it. Experimentation is underway to find out if mercaptan, the odourant added to natural gas to give it a sulphuric smell, is also compatible with hydrogen.

But for all the challenges that might come with switching to hydrogen, there are huge advantages.

The UK’s gas network – both power generation and domestic – must move away from fossil fuels if it is to stop emitting CO2 into the atmosphere, and for the country to reach net zero by 2050. While the process will not be as simple as switching gases, it creates an opportunity to upgrade the UK’s gas infrastructure – for power, in homes and even as a vehicle fuel.

It won’t happen overnight, but hydrogen is a proven energy fuel source. While it may take time to ramp up production to a scale which can meet demand, at a reasonable cost, transitioning to hydrogen is a chance to future-proof the gas systems that contributes so heavily to the UK’s stable power system.

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.

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

27 June 2019

Carbon capture
A model fuel cell car

NASA Museum, Houston, Texas

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

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

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

Power through reaction

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

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

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

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

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

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

Fuel cells as a battery alternative

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

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

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

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

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

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

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

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

Turning CO2 to power

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

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

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

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

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

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

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

During a government-supported front end engineering and design (FEED) study starting this spring, this CO2 will also be captured, then fed through a pipeline running from Drax Power Station into the greenhouse of a nearby salad grower. Here it will act to accelerate the growth of tomatoes.

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

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

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

Could turning carbon dioxide into fish food feed the future?

17 June 2019

Carbon capture
Fisherman boiling shrimps on board of shrimp boat fishing for shrimps on the North Sea

Reducing carbon dioxide (CO2) emissions is one today’s greatest global challenges. But it‘s far from the only issue the world faces. The global population is expected to grow by a third to hit 10 billion by 2050 – an incredible growth that will place huge stress on securing a sustainable source of nutritious, healthy food for future generations.

One UK start-up, Deep Branch Biotechnology, is aiming to tackle both problems with a single solution that utilises captured CO2 emissions to create animal feed protein. In the past, Drax has explored using CO2 captured from its biomass units to help prevent a looming summer beer shortage. Now it’s partnering with Deep Branch to test if captured CO2 can solve some of agriculture’s most-pressing problems.

Broken food chain

The amount of land and resources dedicated to producing animal feed is increasingly unsustainable. A third of all the earth’s cropland is currently used to grow feed crops for livestock, which adds up to more than 90% of all global soy, and 60% of all cereals.

Soy seedlings

“The process of creating the protein we eat on our plates is extremely resource inefficient,” says Peter Rowe, Deep Branch CEO. “It takes about 6 kilograms (kg) of feed to produce one kg of pork. Soy is one of the world’s most widely produced crops but more than 90% of it goes into animal feed.”

It’s not just on land where feed crops are creating problems. Of fish caught around the world, an incredible 25% is processed into fishmeal for the aquaculture, or fish farming, industry. The demand for fishmeal is such that at present it outpaces demand for fish.

Even with an increasing number of people shifting to meat-free diets and more alternatives making headlines, meat production is still expected to double by 2050.

These industries need serious overhauls if they are to sustain into the coming decades. Deep Branch, helped via funding from Innovate UK, is looking to aquaculture as a test bed for sustainable protein production whilst also encouraging CO2 capture.

Turning carbon to carp

The secret behind Deep Branch’s approach to turning emissions into fish food is a strain of bacteria that feeds on CO2.

The partnership will see Deep Branch connect directly to a source of CO2, with the start-up taking up residence in Drax’s carbon capture usage and storage (CCUS) incubator space. Here, flue gas from one of Drax’s biomass power generation units will be fed into Deep Branch’s system, along with hydrogen, enabling a process known as gas fermentation to take place.

“Normally when people think of fermentation, they think about something like wine, where sugar is converted into alcohol with a yeast acting as the biological catalyst,” says Rowe. “Our process, however, uses CO2 and hydrogen instead of sugar. Rather than yeast, our proprietary bacterium acts as the biological catalyst and converts these gases into protein.”

The resulting product is single cell protein, which comes out as a milk-like liquid when harvested. It’s then dried into powder and 70% of what remains are proteins that can be used as a fishmeal replacement.

One of the advantages of Deep Branch’s system is that rather than requiring energy to separate CO2, flue gas can be delivered directly to microbes, which can convert up to 70% of the captured CO2 into proteins. But for such a system to have a real impact it needs to be deployed at scale.

Scaling up

The process has been trialled in labs and proved highly efficient, with ten kg of CO2 producing seven kg of protein. What this new partnership with Drax offers is the opportunity to test Deep Branch’s process and technology at grid-scale. And while Deep Branch is focusing on aquaculture for now, the concept could potentially reach much further through the food chain.

Fish feed

“Because Drax’s biomass units are carbon neutral at the point of generation, the process creates an extremely low-carbon protein,” explains Rowe. “If you divorce the negative environmental impacts of industries like agriculture from its growth then you can provide more whilst impacting less.”

Deployed at global scale the idea of carbon-neutral protein would free up some of the arable land currently being used for soy and other feed crops. It means that as well as cutting the carbon intensity of traditional protein sources, more land would be available for other uses, while helping to halt climate change.

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

Heating the future

9 April 2019

Sustainable bioenergy

We all want our homes and our workplaces to be warm and cosy, but not at the cost of catastrophic climate change. That’s why decarbonising our heating is a challenge that simply cannot be ignored.

Making decisions about how this is done requires careful consideration and a detailed, deliverable national strategy.

Here we discuss the key issues in decarbonising heat.

The numbers

The Climate Change Act commits the UK to reducing its carbon emissions by at least 80 per cent of their 1990 levels by 2050.

As heating our homes and workplaces is responsible for almost one fifth of our country’s total carbon emissions, we are clearly going to need to make huge changes to the way we keep our homes and workplaces warm in order to meet those commitments.

‘Over 80% of energy used in homes is for heating – suggesting large potential for continued decarbonisation.’

— Energising Britain: Progress, impacts and outlook for transforming Britain’s energy system, by I. Staffell, M. Jansen, A. Chase, C. Lewis and E. Cotton, 2018.

Improved insulation, greater energy efficiency and electrification will all reduce the need for fossil fuel-based heating. However, domestic energy efficiency in the UK is lagging well behind targets, although the situation varies from region to region – and such targets do not even exist yet for the non-domestic sector.

Roof insulation material

Even in a low or zero-carbon future, we’re still going to need to keep our homes and workplaces warm – and affordably.

Future policy

Against this backdrop, in March 2018, the UK Government issued a call for evidence for a Future Framework for Heat in Buildings.

Chancellor Phillip Hammond introduced a new ‘future homes standard’ in his 2019 Spring Budget Statement, “mandating the end of fossil fuel heating systems.” Gas boilers will be banned from all new homes from 2025.

A major change is coming. But what else will we need to change in order to transform our heating systems?

1. More electrification

The most noticeable change in the way we heat our homes and workspaces in the future may well come from the need to switch from systems that fuelled by natural gas to ones that are driven by electricity.

Some technologies that can offer a solution to the challenge of decarbonising heating depend on a significant amount of electricity to keep the warmth flowing.

For instance, the hybrid heat pump scenario which is currently supported by the Committee on Climate Change would see up to 85% of a consumer’s need for heat being met by low-carbon electricity.

To give some context to that figure, according to the Committee, 85 per cent of the UK’s homes now rely on fossil-fuel derived natural gas for heating and hot water, and on average these: “currently emit around 2tCO2 per household per year… which represents around one tenth of the average UK household’s carbon footprint.”

Changing from a situation where our heating depends on 85% fossil fuel gas to one that depends on 85% low or zero carbon electricity is little short of a complete transformation. Given that the new future homes standard is due to be introduced in less than six years, this transformation will need to happen quickly.

Of course, a great deal of the extra electricity needed will come from intermittent renewables such as wind turbines and solar panels – especially as the cost of renewable electricity is falling.

Much of that power looks likely to be supplied by distributed sources rather than those integrated into the national grid. Indeed, since 2011, power generation capacity connected directly to the distribution network grew from 12 gigawatts (GW) to more than 40 GW by the end of 2017, according to estimates from energy experts Cornwall Insight in a report for our B2B energy supply business, Haven Power.

With so much of our electricity reliant on the weather, there will still be a need for dispatchable and flexible thermal sources and energy storage, such as Drax and Cruachan power stations. Their centralised power generation can be turned up and fed directly into the national transmission system at short notice, to keep our heating running and our homes warm.

Dam and reservoir, Cruachan Power Station, Scotland

Such a transformation will obviously require careful strategic planning as well as an enormous amount of investment.

There may well be no single solution to the challenge of heat decarbonisation, rather a number of different solutions that depend on where people live and work, their individual circumstances, the energy efficiency of their homes and the resources they have close at hand.

But while it has previously been reported that the overall or system costs of electrifying heating could be as much as three times the cost of using gas, another study suggests that the costs could be much closer.

2. More heat pumps

Heat pumps that absorb environmental warmth and use it to provide low carbon heating have always been considered a possible option for the four million homes and countless workplaces that are not currently connected to the UK’s mains gas network.

Recently expert opinion has been changing with hybrid heat pumps seen as a workable solution even for homes and workplaces that are connected to gas supplies. Indeed, in 2018 the Committee on Climate Change stated that hybrid heat pumps: “can be the lowest cost option where homes are sufficiently insulated, or can be insulated affordably.” This means that they may be one of the simplest and most affordable options to provide the heating of the future.

Hybrid heat pumps draw heat from the air or ground around them and use a boiler to provide extra heat when the weather is exceptionally cold. In a low carbon future, that boiler could be fuelled by biogas. In a zero carbon situation, it could be powered by hydrogen.

Heat pumps can be air-source (ASHP) – absorbing warmth from the atmosphere like the heat exchanger in your fridge in reverse – or ground source (GSHP). GSHPs absorb heat through on a network of pipes (a ground loop) buried or a vertical borehole drilled in the earth outside your home or workplace.

Both ASHPs and GSHPs can be used to support underfloor heating or a radiator system, though neither will provide water heated to the high temperature a natural gas boiler will reach to keep radiators hot.

And even though the warmth they absorb is free, heat pumps depend on a supply of electricity to condense it and to bring it back to the heating system inside the house.

This electricity could be generated by distributed power from local solar PV, wind turbines, drawn from batteries or even from the low carbon grid of the future.

It is worth noting that the size of heat pumps and the amount of land they require – especially GSHP – makes them a less attractive solution for people who live or work in built up areas such as cities. While for those who live in blocks of flats, it is difficult to see how individual heat pumps could be a practical solution.

3. More hydrogen

The idea of switching the mains gas grid to store and transport hydrogen has long appealed as a potential solution to the challenge of decarbonising heating. Renewable hydrogen could then be burnt in domestic boilers similar to those we currently use for natural gas.

The benefits are many. Hydrogen produces no carbon emissions when burnt, and can be stored and transported in much the same way as natural gas (provided old metal pipes have been replaced with modern alternatives).

And given the sunk costs involved in the existing gas grid and in the network of pipes and radiators already installed in tens of millions of homes, hydrogen has always been expected to be the lowest cost option too.

However, according to the Committee on Climate Change’s latest findings, hydrogen should not be seen as a ‘silver bullet’ solution, capable of transforming our entire heating landscape in a single change.

The main reasons they give for this judgment are the relatively high cost of the electricity required to produce sufficient hydrogen to power tens of millions of boilers, the undesirability of relying on substantial imports of hydrogen, and the lack of a carbon-free method to supply the gas cost-effectively at scale.

Hydrogen could, however, be produced by gas reformation of the emissions retained by bioenergy carbon capture and storage (BECCS) such as that being pioneered at Drax Power Station. Carbon capture use and storage (CCUS), of which BECCS is the renewable variant, is supported by the UK government through its Clean Growth Strategy as it has potential to accelerate decarbonisation in power and industrial sectors.

Extremely rapid progress to provide hydrogen in sufficient quantities from BECCS is unlikely – but the first schemes could begin operating in the late 2020s.

Hydrogen production also has the potential to radically transform the economics of CCUS, making it a much more attractive investment.

It was originally assumed that the power required to drive the energy-intensive process of hydrogen created via electrolysis would come from surplus electricity generated by intermittent renewables at times of low demand. However, that surplus is not now generally regarded as likely to be sufficiently large to be relied upon. 

It is these limitations, together with a comprehensive model of the likely costs involved in different approaches to decarbonisation, that led the Committee on Climate Change to suggest that hybrid heat pumps could provide the bulk of domestic heating in the future.

At present, it seems likely that converting to hydrogen-fuelled boilers will mainly be an attractive option for those who live and work near areas where the renewable fuel can be most easily created and stored. The north of England is a prime example – close to the energy and carbon intensive areas of the Humber and Tees valleys where CCUS and hydrogen clusters could be located with good access to North Sea carbon stores such as aquifers and former gas fields.

4. More solar

Many homes in the UK – especially in the south – could be heated electrically without carbon emissions at the point of use.

Solar thermal (for water heating) or solar PVs (for electric and water heating) common sights on domestic property rooftops. The intermittency of solar power need not be an issue as the electricity generated could then be stored in batteries ‘behind the meter’ until it is needed.

However, the lack of sufficient daylight for much of the year in many parts of the UK could, together with the still relatively high cost of battery storage, still mean that this would not necessarily be a solution that can be applied at scale to millions of homes and workplaces all year round.

As the cost of battery storage continues to fall, it may well be that solar becomes a more practical and cost-effective solution.

5. More biomass

More geothermal

Sustainably sourced compressed wood pellets and biomass boilers have long been proposed as a potential solution to decarbonising heating for the many people who live and work off the mains gas grid. Bioenergy as a whole – including biogas as well as wood pellets – now provides around four percent of UK heat, up from 1.4% in 2008.

The main barriers to this are the current relatively high cost of biomass boilers. This is currently offset by the Renewable Heating Incentive (RHI) which the UK government has committed to continuing until 2021.

As this solution is adopted by more consumers, it is anticipated that the real costs of such new technology will fall as economies of scale start to take effect in much the same way that solar PV and battery technology has recently become more affordable.

6. More geothermal

Ruins of a tin mine, Wheal Coates Mine, St. Agnes, Cornwall, England

Geothermal energy uses the heat stored beneath the surface of our planet itself to provide the energy we need.

While in some countries such as Iceland, geothermal energy is used to drive turbines to generate electricity that is then used to provide power for heating, it is envisaged that in the UK it could be converted into warmth through massive heat pumps that provide heating to entire communities – especially those in former mining areas. There is already one geothermal district heating scheme in operation in the UK, in Southampton.

It is envisaged that such geothermal schemes would work most effectively at a district level, providing zero carbon heat to many homes and workplaces. According to a recent report, geothermal energy has the potential to “produce up to 20 per cent of UK electricity and heat for millions.”

At present, drilling is being carried out to see if geothermal heating could be viable in Cornwall. However, there is no reason why it could not be used in disused coalmines too where ground source heat pumps (GSHPs) would absorb and condense the required heat. This means that geothermal could have strong potential as a solution to the challenge of decarbonisation for former mining communities.

7. More CHP

Cory Riverside Energy’s Resource Recovery Facility in Belvedere, London, could be operated as a CHP plant in the future

By using the heat created in thermal renewable electricity generation – such as biomass – in combined heat and power schemes, businesses and individuals can reduce their energy costs and their carbon emissions. Such schemes can work well for new developments on a district basis, and are already popular in mainland Europe, especially Sweden, Denmark and Switzerland.

Warm homes, factories and offices

There are already a number of viable solutions to decarbonising heating in the UK. They rely on smart policy, smarter technology and customers taking control of their energy.

Rather than any one of these technologies providing a single solution that can help every consumer and business in the country to meet the challenge in the same way, it is more likely that it will be met by a number of different solutions, depending on geography, cost and individual circumstances. These will sometimes also work in concert rather than alone.

The UK has made solid progress on reducing carbon emissions – especially in power generation. When it comes to heating buildings, rapid decarbonisation is now needed. And that decarbonisation must avoid fuel poverty and help to rebalance the economy.

Find out more about energy in buildings in Energising Britain: Progress, impacts and outlook for transforming Britain’s energy system.