̽��ֱ�� of Cambridge - renewable

Solar-powered device captures carbon dioxide from air to make sustainable fuel

sc604 — Thu, 13 Feb 2025 10:00:00 +0000

̽��ֱ��researchers, from the ̽��ֱ�� of Cambridge, say their solar-powered reactor could be used to make fuel to power cars and planes, or the many chemicals and pharmaceuticals products we rely on. It could also be used to generate fuel in remote or off-grid locations.

Unlike most carbon capture technologies, the reactor developed by the Cambridge researchers does not require fossil-fuel-based power, or the transport and storage of carbon dioxide, but instead converts atmospheric CO2 into something useful using sunlight. ̽��ֱ��results are reported in the journal Nature Energy.

Carbon Capture and Storage (CCS) has been touted as a possible solution to the climate crisis, and has recently received £22bn in funding from the UK government. However, CCS is energy-intensive and there are concerns about the long-term safety of storing pressurised CO2 deep underground, although safety studies are currently being carried out.

“Aside from the expense and the energy intensity, CCS provides an excuse to carry on burning fossil fuels, which is what caused the climate crisis in the first place,” said Professor Erwin Reisner, who led the research. “CCS is also a non-circular process, since the pressurised CO2 is, at best, stored underground indefinitely, where it’s of no use to anyone.”

“What if instead of pumping the carbon dioxide underground, we made something useful from it?” said first author Dr Sayan Kar from Cambridge’s Yusuf Hamied Department of Chemistry. “CO2 is a harmful greenhouse gas, but it can also be turned into useful chemicals without contributing to global warming.”

̽��ֱ��focus of Reisner’s research group is the development of devices that convert waste, water and air into practical fuels and chemicals. These devices take their inspiration from photosynthesis: the process by which plants convert sunlight into food. ̽��ֱ��devices don’t use any outside power: no cables, no batteries – all they need is the power of the sun.

̽��ֱ��team’s newest system takes CO2 directly from the air and converts it into syngas: a key intermediate in the production of many chemicals and pharmaceuticals. ̽��ֱ��researchers say their approach, which does not require any transportation or storage, is much easier to scale up than earlier solar-powered devices.

̽��ֱ��device, a solar-powered flow reactor, uses specialised filters to grab CO2 from the air at night, like how a sponge soaks up water. When the sun comes out, the sunlight heats up the captured CO2, absorbing infrared radiation and a semiconductor powder absorbs the ultraviolet radiation to start a chemical reaction that converts the captured CO2 into solar syngas. A mirror on the reactor concentrates the sunlight, making the process more efficient.

̽��ֱ��researchers are currently working on converting the solar syngas into liquid fuels, which could be used to power cars, planes and more – without adding more CO2 to the atmosphere.

“If we made these devices at scale, they could solve two problems at once: removing CO2 from the atmosphere and creating a clean alternative to fossil fuels,” said Kar. “CO2 is seen as a harmful waste product, but it is also an opportunity.”

̽��ֱ��researchers say that a particularly promising opportunity is in the chemical and pharmaceutical sector, where syngas can be converted into many of the products we rely on every day, without contributing to climate change. They are building a larger scale version of the reactor and hope to begin tests in the spring.

If scaled up, the researchers say their reactor could be used in a decentralised way, so that individuals could theoretically generate their own fuel, which would be useful in remote or off-grid locations.

“Instead of continuing to dig up and burn fossil fuels to produce the products we have come to rely on, we can get all the CO2 we need directly from the air and reuse it,” said Reisner. “We can build a circular, sustainable economy – if we have the political will to do it.”

̽��ֱ��technology is being commercialised with the support of Cambridge Enterprise, the ̽��ֱ��’s commercialisation arm. ̽��ֱ��research was supported in part by UK Research and Innovation (UKRI), the European Research Council, the Royal Academy of Engineering, and the Cambridge Trust. Erwin Reisner is a Fellow of St John’s College, Cambridge.

Reference:
Sayan Kar et al. ‘Direct air capture of CO2 for solar fuels production in flow.’ Nature Energy (2025). DOI: 10.1038/s41560-025-01714-y

For more information on energy-related research in Cambridge, please visit the Energy IRC, which brings together Cambridge’s research knowledge and expertise, in collaboration with global partners, to create solutions for a sustainable and resilient energy landscape for generations to come.

Researchers have developed a reactor that pulls carbon dioxide directly from the air and converts it into sustainable fuel, using sunlight as the power source.

We can build a circular, sustainable economy – if we have the political will to do it

Erwin Reisner

Sayan Kar

Solar-powered flow reactor

̽��ֱ��text in this work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. Images, including our videos, are Copyright © ̽��ֱ�� of Cambridge and licensors/contributors as identified. All rights reserved. We make our image and video content available in a number of ways – on our main website under its Terms and conditions, and on a range of channels including social media that permit your use and sharing of our content under their respective Terms.

Yes

Electricity prices across Europe to stabilise if 2030 targets for renewable energy are met

fpjl2 — Mon, 03 Feb 2025 10:24:42 +0000

Hitting the current national 2030 quotas for solar and wind energy could reduce the volatility of electricity markets by an average of 20% across 29 European countries, according to a new study from the ̽��ֱ�� of Cambridge.

̽��ֱ��intensity of spikes in power prices are predicted to fall in every country by the end of the decade if commitments to green energy are met, as natural gas dependency is cut.

̽��ֱ��UK and Ireland would be the biggest beneficiaries, with 44% and 43% reductions in the severity of electricity price spikes by 2030, compared with last year.

Germany could experience a 31% decline in electricity price volatility, with the Netherlands and Belgium seeing price spikes ease by 38% and 33% respectively.

̽��ֱ��simulations conducted for the new study show that scaling up renewable energy minimises the market impact of fluctuations in natural gas price – increasing stability even when considering the reliance of renewable technologies on weather.

Some EU leaders and energy ministers have called for renewables targets on grounds of energy security as well as decarbonisation, particularly since Putin’s war on Ukraine stemmed the flow of Russian gas.

̽��ֱ��study, published in the journal Nature Energy, calculates in detail how such aims would affect the volatility of wholesale electricity prices in energy markets across Europe.

“ ̽��ֱ��volatility of energy prices is a major cause of damage to national economies,” said Laura Diaz Anadon, the ̽��ֱ�� of Cambridge’s Professor of Climate Change Policy.

“Consumers are still reeling from sharp increases in electricity prices brought about by natural gas shortages following Russia’s invasion of Ukraine,” said Anadon. “We show that hitting renewables targets reduce the likelihood of such price spikes in the future.”

Daniel Navia, a researcher with the ̽��ֱ��’s Centre for Environment, Energy and Natural Resource Governance (CEENRG), said: “Meeting renewable energy targets is not only good for carbon neutrality, but we can see it is a boost to economic resilience”

“We had probably underestimated how costly energy price shocks are to our societies, and the last crisis has been a stark reminder.”

̽��ֱ��Cambridge researchers used the ̽��ֱ��’s high performance computing facilities to model a wide range of factors – from fluctuations in weather patterns and energy demands to fuel capacity – to map the current and future grids of all 27 EU nations plus the UK and Switzerland.

They assessed electricity markets in 2030 based on the commitments to renewables as stated in each nation’s national energy and climate plan.

“ ̽��ֱ��UK in particular is projected to see major benefits to its energy market stability from renewables,” said Anadon.

“ ̽��ֱ��UK has struggled with its exposure to gas prices due to a lack of energy storage and limited connections to the European grid. This has led to more hours where electricity prices are set by natural gas.”

̽��ֱ��research also suggests that wholesale prices of electricity could fall by over a quarter on average across all countries in the study by decade’s end if they stick to current national renewables targets.

Again, populations in the UK and Ireland stand to gain significantly, with electricity prices predicted to fall by around 45% by 2030, compared with the current situation.

Several of the Nordic nations could see over 60% reductions in electricity costs by 2030, while in Germany the price is predicted to fall by 34%, with Belgium seeing a similar drop of 31%. ̽��ֱ��study suggests the Netherlands could see the price of electricity fall by 41%.

While the study’s authors caution that trends in electricity prices depend on factors that are “impossible to predict”, they say their results are in line with recent outputs by institutions such as the International Energy Agency.

In fact, Navia and Anadon say their modelling may even underestimate the potential for electricity price stability across Europe, as the projections were calculated using data from 1990-2021 – before the energy crisis created by Russia’s attack on Ukraine.

“It makes sense to think about renewables as a security investment, and if we lose the momentum towards green energy, we are clearly harming the climate, but we also exposing ourselves to unknowable risks down the line,” said Anadon.

̽��ֱ��new study also charts the effects on electricity prices if countries overshoot on renewables. If Europe exceeds its renewable energy goals by 30%, electricity prices could become 50% less sensitive to natural gas, compared to just meeting renewables targets.

However, the study suggests there are tipping points where renewables cause the price of power to fall so far that it stops providing sufficient return on investment, and the green energy industries may stall.

Added Navia: “If we are to fully utilise solar and wind as a security tool, Europe might have to rethink how its energy markets are designed, and what incentives it can offer the private sector to maintain the societal insurance value it gets from renewable energy.”

National targets for solar and wind power will see reliance on natural gas plummet, reducing electricity price volatility across Europe, with major beneficiaries including the UK and Ireland, the Nordics, and the Netherlands.

̽��ֱ��UK in particular is projected to see major benefits to its energy market stability from renewables

Laura Diaz Anadon

Anton Petrus via Getty images

High voltage electricity towers combined with economic charts

Yes

Tiny copper ‘flowers’ bloom on artificial leaves for clean fuel production

sc604 — Mon, 03 Feb 2025 09:28:45 +0000

̽��ֱ��researchers, from the ̽��ֱ�� of Cambridge and the ̽��ֱ�� of California, Berkeley, developed a practical way to make hydrocarbons – molecules made of carbon and hydrogen – powered solely by the sun.

̽��ֱ��device they developed combines a light absorbing ‘leaf’ made from a high-efficiency solar cell material called perovskite, with a copper nanoflower catalyst, to convert carbon dioxide into useful molecules. Unlike most metal catalysts, which can only convert CO₂ into single-carbon molecules, the copper flowers enable the formation of more complex hydrocarbons with two carbon atoms, such as ethane and ethylene — key building blocks for liquid fuels, chemicals and plastics.

Almost all hydrocarbons currently stem from fossil fuels, but the method developed by the Cambridge-Berkeley team results in clean chemicals and fuels made from CO2, water and glycerol – a common organic compound – without any additional carbon emissions. ̽��ֱ��results are reported in the journal Nature Catalysis.

̽��ֱ��study builds on the team’s earlier work on artificial leaves, which take their inspiration from photosynthesis: the process by which plants convert sunlight into food. “We wanted to go beyond basic carbon dioxide reduction and produce more complex hydrocarbons, but that requires significantly more energy,” said Dr Virgil Andrei from Cambridge’s Yusuf Hamied Department of Chemistry, the study’s lead author.

Andrei, a Research Fellow of St John’s College, Cambridge, carried out the work as part of the Winton Cambridge-Kavli ENSI Exchange programme in the lab of Professor Peidong Yang at ̽��ֱ�� of California, Berkeley.

By coupling a perovskite light absorber with the copper nanoflower catalyst, the team was able to produce more complex hydrocarbons. To further improve efficiency and overcome the energy limits of splitting water, the team added silicon nanowire electrodes that can oxidise glycerol instead. This new platform produces hydrocarbons much more effectively — 200 times better than earlier systems for splitting water and carbon dioxide.

̽��ֱ��reaction not only boosts CO₂ reduction performance, but also produces high-value chemicals such as glycerate, lactate, and formate, which have applications in pharmaceuticals, cosmetics, and chemical synthesis.

“Glycerol is typically considered waste, but here it plays a crucial role in improving the reaction rate,” said Andrei. “This demonstrates we can apply our platform to a wide range of chemical processes beyond just waste conversion. By carefully designing the catalyst’s surface area, we can influence what products we generate, making the process more selective.”

While current CO₂-to-hydrocarbon selectivity remains around 10%, the researchers are optimistic about improving catalyst design to increase efficiency. ̽��ֱ��team envisions applying their platform to even more complex organic reactions, opening doors for innovation in sustainable chemical production. With continued improvements, this research could accelerate the transition to a circular, carbon-neutral economy.

“This project is an excellent example of how global research partnerships can lead to impactful scientific advancements,” said Andrei. “By combining expertise from Cambridge and Berkeley, we’ve developed a system that may reshape the way we produce fuels and valuable chemicals sustainably.”

̽��ֱ��research was supported in part by the Winton Programme for the Physics of Sustainability, St John’s College, the US Department of Energy, the European Research Council, and UK Research and Innovation (UKRI).

Reference:
Virgil Andrei et al. ‘Perovskite-driven solar C2 hydrocarbon synthesis from CO2.’ Nature Catalysis (2025). DOI: 10.1038/s41929-025-01292-y

Tiny copper ‘nano-flowers’ have been attached to an artificial leaf to produce clean fuels and chemicals that are the backbone of modern energy and manufacturing.

Virgil Andrei

Solar fuel generator

Yes

Trash into treasure: making clean fuel from waste and sunlight

sc604 — Wed, 09 Oct 2024 14:22:55 +0000

Professor Erwin Reisner and his team are developing prototype devices that convert waste, water and air into practical fuels and chemicals.

̽��ֱ��cost of solar power: how low can we go?

sc604 — Tue, 08 Oct 2024 14:27:07 +0000

Professor Sam Stranks is developing next-generation solar cell technology, which could drive down renewable energy prices even further.

A simple ‘twist’ improves the engine of clean fuel generation

sc604 — Wed, 24 Apr 2024 14:31:37 +0000

̽��ֱ��researchers, led by the ̽��ֱ�� of Cambridge, are developing low-cost light-harvesting semiconductors that power devices for converting water into clean hydrogen fuel, using just the power of the sun. These semiconducting materials, known as copper oxides, are cheap, abundant and non-toxic, but their performance does not come close to silicon, which dominates the semiconductor market.

However, the researchers found that by growing the copper oxide crystals in a specific orientation so that electric charges move through the crystals at a diagonal, the charges move much faster and further, greatly improving performance. Tests of a copper oxide light harvester, or photocathode, based on this fabrication technique showed a 70% improvement over existing state-of-the-art oxide photocathodes, while also showing greatly improved stability.

̽��ֱ��researchers say their results, reported in the journal Nature, show how low-cost materials could be fine-tuned to power the transition away from fossil fuels and toward clean, sustainable fuels that can be stored and used with existing energy infrastructure.

Copper (I) oxide, or cuprous oxide, has been touted as a cheap potential replacement for silicon for years, since it is reasonably effective at capturing sunlight and converting it into electric charge. However, much of that charge tends to get lost, limiting the material’s performance.

“Like other oxide semiconductors, cuprous oxide has its intrinsic challenges,” said co-first author Dr Linfeng Pan from Cambridge’s Department of Chemical Engineering and Biotechnology. “One of those challenges is the mismatch between how deep light is absorbed and how far the charges travel within the material, so most of the oxide below the top layer of material is essentially dead space.”

“For most solar cell materials, it’s defects on the surface of the material that cause a reduction in performance, but with these oxide materials, it’s the other way round: the surface is largely fine, but something about the bulk leads to losses,” said Professor Sam Stranks, who led the research. “This means the way the crystals are grown is vital to their performance.”

To develop cuprous oxides to the point where they can be a credible contender to established photovoltaic materials, they need to be optimised so they can efficiently generate and move electric charges – made of an electron and a positively-charged electron ‘hole’ – when sunlight hits them.

One potential optimisation approach is single-crystal thin films – very thin slices of material with a highly-ordered crystal structure, which are often used in electronics. However, making these films is normally a complex and time-consuming process.

Using thin film deposition techniques, the researchers were able to grow high-quality cuprous oxide films at ambient pressure and room temperature. By precisely controlling growth and flow rates in the chamber, they were able to ‘shift’ the crystals into a particular orientation. Then, using high temporal resolution spectroscopic techniques, they were able to observe how the orientation of the crystals affected how efficiently electric charges moved through the material.

“These crystals are basically cubes, and we found that when the electrons move through the cube at a body diagonal, rather than along the face or edge of the cube, they move an order of magnitude further,” said Pan. “ ̽��ֱ��further the electrons move, the better the performance.”

“Something about that diagonal direction in these materials is magic,” said Stranks. “We need to carry out further work to fully understand why and optimise it further, but it has so far resulted in a huge jump in performance.” Tests of a cuprous oxide photocathode made using this technique showed an increase in performance of more than 70% over existing state-of-the-art electrodeposited oxide photocathodes.

“In addition to the improved performance, we found that the orientation makes the films much more stable, but factors beyond the bulk properties may be at play,” said Pan.

̽��ֱ��researchers say that much more research and development is still needed, but this and related families of materials could have a vital role in the energy transition.

“There’s still a long way to go, but we’re on an exciting trajectory,” said Stranks. “There’s a lot of interesting science to come from these materials, and it’s interesting for me to connect the physics of these materials with their growth, how they form, and ultimately how they perform.”

̽��ֱ��research was a collaboration with École Polytechnique Fédérale de Lausanne, Nankai ̽��ֱ�� and Uppsala ̽��ֱ��. ̽��ֱ��research was supported in part by the European Research Council, the Swiss National Science Foundation, and the Engineering and Physical Sciences Research Council (EPSRC), part of UK Research and Innovation (UKRI). Sam Stranks is Professor of Optoelectronics in the Department of Chemical Engineering and Biotechnology, and a Fellow of Clare College, Cambridge.

Reference:
Linfeng Pan, Linjie Dai et al. ‘High carrier mobility along the [111] orientation in Cu2O photoelectrodes.’ Nature (2024). DOI: 10.1038/s41586-024-07273-8

Researchers have found a way to super-charge the ‘engine’ of sustainable fuel generation – by giving the materials a little twist.

orange via Getty Images

Abstract orange swirls

Yes

Solar-powered device produces clean water and clean fuel at the same time

sc604 — Mon, 13 Nov 2023 16:21:43 +0000

̽��ֱ��device, developed by researchers at the ̽��ֱ�� of Cambridge, could be useful in resource-limited or off-grid environments, since it works with any open water source and does not require any outside power.

It takes its inspiration from photosynthesis, the process by which plants convert sunlight into food. However, unlike earlier versions of the ‘artificial leaf’, which could produce green hydrogen fuel from clean water sources, this new device operates from polluted or seawater sources and can produce clean drinking water at the same time.

Tests of the device showed it was able to produce clean water from highly polluted water, seawater, and even from the River Cam in central Cambridge. ̽��ֱ��results are reported in the journal Nature Water.

“Bringing together solar fuels production and water purification in a single device is tricky,” said Dr Chanon Pornrungroj from Cambridge’s Yusuf Hamied Department of Chemistry, the paper’s co-lead author. “Solar-driven water splitting, where water molecules are broken down into hydrogen and oxygen, need to start with totally pure water because any contaminants can poison the catalyst or cause unwanted chemical side-reactions.”

“In remote or developing regions, where clean water is relatively scarce and the infrastructure necessary for water purification is not readily available, water splitting is extremely difficult,” said co-lead author Ariffin Mohamad Annuar. “A device that could work using contaminated water could solve two problems at once: it could split water to make clean fuel, and it could make clean drinking water.”

Pornrungroj and Mohamad Annuar, who are both members of Professor Erwin Reisner’s research group, came up with a design that did just that. They deposited a photocatalyst on a nanostructured carbon mesh that is a good absorber of both light and heat, generating the water vapour used by the photocatalyst to create hydrogen. ̽��ֱ��porous carbon mesh, treated to repel water, served both to help the photocatalyst float and to keep it away from the water below, so that contaminants do not interfere with its functionality.

In addition, the new device uses more of the Sun’s energy. “ ̽��ֱ��light-driven process for making solar fuels only uses a small portion of the solar spectrum – there’s a whole lot of the spectrum that goes unused,” said Mohamad Annuar.

̽��ֱ��team used a white, UV-absorbing layer on top of the floating device for hydrogen production via water splitting. ̽��ֱ��rest of the light in the solar spectrum is transmitted to the bottom of the device, which vaporises the water.

“This way, we’re making better use of the light – we get the vapour for hydrogen production, and the rest is water vapour,” said Pornrungroj. “This way, we’re truly mimicking a real leaf, since we’ve now been able to incorporate the process of transpiration.”

A device that can make clean fuel and clean water at once using solar power alone could help address the energy and the water crises facing so many parts of the world. For example, the indoor air pollution caused by cooking with ‘dirty’ fuels, such as kerosene, is responsible for more than three million deaths annually, according to the World Health Organization. Cooking with green hydrogen instead could help reduce that number significantly. And 1.8 billion people worldwide still lack safe drinking water at home.

“It’s such a simple design as well: in just a few steps, we can build a device that works well on water from a wide variety of sources,” said Mohamad Annuar.

“It’s so tolerant of pollutants, and the floating design allows the substrate to work in very cloudy or muddy water,” said Pornrungroj. “It’s a highly versatile system.”

“Our device is still a proof of principle, but these are the sorts of solutions we will need if we’re going to develop a truly circular economy and sustainable future,” said Reisner, who led the research. “ ̽��ֱ��climate crisis and issues around pollution and health are closely related, and developing an approach that could help address both would be a game-changer for so many people.”

̽��ֱ��research was supported in part by the European Commission’s Horizon 2020 programme, ̽��ֱ��European Research Council, the Cambridge Trust, the Petronas Education Sponsorship Programme, and the Winton Programme for the Physics of Sustainability. Erwin Reisner is a Fellow of St John’s College. Chanon Pornrungroj is a member of Darwin College, and Ariffin Mohamad Annuar is a member of Clare College.

Reference:
Chanon Pornrungroj, Ariffin Bin Mohamad Annuar et al. ‘Hybrid photothermal-photocatalyst sheets for solar-driven overall water splitting coupled to water purification.’ Nature Water (2023). DOI: 10.1038/s44221-023-00139-9

A floating, solar-powered device that can turn contaminated water or seawater into clean hydrogen fuel and purified water, anywhere in the world, has been developed by researchers.

These are the sorts of solutions we will need to develop a truly circular economy and sustainable future

Erwin Reisner

Chanon Pornrungroj

Device for making solar fuels on the River Cam near the Bridge of Sighs

̽��ֱ��text in this work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. Images, including our videos, are Copyright © ̽��ֱ�� of Cambridge and licensors/contributors as identified. All rights reserved. We make our image and video content available in a number of ways – as here, on our main website under its Terms and conditions, and on a range of channels including social media that permit your use and sharing of our content under their respective Terms.

Yes

Photosynthesis ‘hack’ could lead to new ways of generating renewable energy

sc604 — Wed, 22 Mar 2023 15:57:53 +0000

Researchers have ‘hacked’ the earliest stages of photosynthesis, the natural machine that powers the vast majority of life on Earth, and discovered new ways to extract energy from the process, a finding that could lead to new ways of generating clean fuel and renewable energy.