Now there’s another idea joining the fray, and it carries the added benefit of playing a role in the renewable energy transition: It’s a tiny house made from the nacelle of a decommissioned wind turbine.

The house, unveiled last month as part of Dutch Design Week, is a collaboration between Swedish power company Vattenfall and Dutch architecture firm Superuse Studios. Wind turbines typically have a 20-year lifespan, and Vattenfall is looking for novel ways to repurpose parts of its turbines. With the first generation of large-scale turbines now reaching the end of their useful life, there will be thousands of nacelles (not to mention blades, towers, and generators) in search of a new purpose.

Blades, towers, and generators are the parts of a wind turbine that most people are familiar with, but not so much the nacelle. The giant rectangular box sits at the top of the turbine’s tower and houses its gearbox, shafts, generator, and brake. It’s the beating heart of the turbine, where the blades’ rotation is converted into electricity.

Though it’s big enough to be a tiny house, this particular nacelle is on the small side (as far as nacelles go). It’s 10 feet tall by 13 feet wide by 33 feet long. The interior space of the home about 387 square feet, or the size of a small studio apartment or hotel room. The nacelle came from one of Vattenfall’s V80 turbines, which was installed at an Austrian wind farm in 2005 and has a production capacity of two megawatts. Turbine technology has come a long way since then; the largest ones in the world are approaching a production capacity of 15 megawatts.

Though there will be larger nacelles available, Superuse Studios intentionally chose a small one for its prototype. Their thinking was, if you can make a livable home in this small of a space, you can definitely make a livable home—and add more features—in a larger space; better to start small and grow than start big then downsize.

Though the house is small, its designers ensured it was fully compliant with Dutch building code and therefore suitable for habitation. It has a kitchen with a sink and a stove, a bathroom with a shower, a dining area, and a combined living/sleeping area. As you’d expect from a house made of recycled wind turbine parts, it’s also climate-friendly: Its electricity comes partly from rooftop solar panels, and it has a bidirectional charger for electric vehicles (meaning power from the house can charge the car or power from the car’s battery can be used in the house). There’s an electric heat pump for temperature control, and a solar heater for hot water.

Solar panels and wind turbines don’t last forever, and they use various raw and engineered materials. When the panels or turbines can’t produce power anymore, what’s to be done with all that concrete, copper, steel, silicon, glass, or aluminum? Finding purposeful ways to reuse or recycle these materials will be a crucial component of a successful transition away from fossil fuels.

“We are looking for innovative ways in which you can reuse materials from used turbines as completely as possible,” said Thomas Hjort, Vattenfall’s director of innovation, in a press release. “So making something new from them with as few modifications as possible. That saves raw materials, energy consumption and in this way we ensure that these materials are useful for many years after their first working life.”

As of right now, the nacelle tiny house is just a proof of concept; there are no plans to start producing more in the immediate future, but it’s not outside the realm of possibility eventually. Picture communities of these houses arranged in rows or circles, with communal spaces or parks in between. Using a larger nacelle, homes with one or two bedrooms could be designed, expanding the possibilities for inhabitants and giving purpose to more decommissioned turbines.

“At least ten thousand of this generation of nacelles are available, spread around the world,” said Jos de Krieger, a partner at Superuse Studios. “Most of them have yet to be decommissioned. This offers perspective and a challenge for owners and decommissioners. If such a complex structure as a house is possible, then numerous simpler solutions are also feasible and scalable.”

If 10,000-plus nacelles are available, that means 30,000-plus blades are available. What innovative use might designers and engineers find for them?

Image Credit: Vattenfall

The biggest challenge when it comes to finding alternatives to fossil fuels in aviation is basic physics. Jet fuel is incredibly energy dense, which is crucial for a mode of transport where weight savings can dramatically impact range.

While efforts are underway to build planes powered by batteries, hydrogen, or methane, none can come close to matching kerosene, pound for pound, at present. Sustainable aviation fuel is another option, but so far, its uptake has been limited, and its green credentials are debatable.

Despite this, the authors of a new report from the University of Cambridge’s Aviation Impact Accelerator (AIA) say that with a concerted effort the industry can clean up its act. The report outlines four key sustainable aviation goals that, if implemented within the next five years, could help the sector become carbon neutral by the middle of the century.

“Too often the discussions about how to achieve sustainable aviation lurch between overly optimistic thinking about current industry efforts and doom-laden cataloging of the sector’s environmental evils,” Eliot Whittington, executive director at the Cambridge Institute for Sustainability Leadership, said in a press release.

“The Aviation Impact Accelerator modeling has drawn on the best available evidence to show that there are major challenges to be navigated if we’re to achieve net zero flying at scale, but that it is possible.”

The report notes that time is of the essence. Aviation is responsible for roughly 4 percent of global warming despite only 10 percent of the population flying, a figure that’s likely to rise as the world continues to develop. Despite global leaders pledging to make aviation net zero, current efforts to get there are not ambitious enough, the authors say.

After researching the interventions that could have the biggest impact and discussions at the inaugural meeting of the Transatlantic Sustainable Aviation Partnership at MIT last year, AIA came up with four focus areas that could put those goals within reach.

The first of these is to reduce contrails. While most of the focus is on emissions from burning jet fuel, the generation of persistent contrails can trap heat in atmosphere and add significantly to warming.

Contrails can be avoided by adjusting an aircraft’s altitude in areas where they’re most likely to be formed, but the underlying science is poorly understood as are potential strategies for adjusting air traffic. Therefore, the report suggests setting up several “living labs” in existing airspace to conduct data collection and experiments. These should be ready by the end of 2025, say the authors.

The second goal is to reduce the amount of fuel airplanes use by introducing new aircraft and engine designs, improving operational efficiency of the sector, or just getting aircraft to fly slower. To catalyze action, governments need to set clear policies, such as establishing fuel burn reduction targets, loan guarantees for new aircraft purchases, or incentives to scrap old airplanes.

The third goal is to ensure sustainable aviation fuel is actually sustainable, and its production is scalable. Most sustainable fuels rely on biomass, but limitations on production and competition from other sectors could mean they can’t realize the hoped for emissions reductions.

In the near term, the report suggests aviation will have to work with other industries to set best practices and limit total cross-sector emissions. And in the long run, the industry will have to make efforts to find alternative ways to develop synthetic sustainable fuels.

Lastly, the report argues the industry also needs to invest in “moonshot” technologies. By 2025, aviation should launch several high-risk, high-reward demonstration programs in technologies that could be truly transformative for the sector. These include the development of cryogenic hydrogen or methane fuels, hydrogen-electric propulsion technology, or the use of synthetic biology to dramatically lower the energy demands for sustainable fuel production.

The report’s authors stress that, although they are confident these interventions could have the desired impact, time is of the essence. History suggests that getting global leaders to take decisive action on climate issues is tricky, but at least they now have a concrete roadmap.

Image Credit: John McArthur / Unsplash

Transportation is the single biggest contributor to climate change in the US—accounting for 28 percent of total greenhouse gas emissions, according to the Environmental Protection Agency. So, the rise of electric vehicles has been one of the biggest success stories in the effort to clean up the economy.

Slowing sales growth for battery-powered cars has some worried there might be a ceiling to the number of people willing to adopt the technology. But Norway shows that with the right incentives, the goal of a completely electrified road network is a tangible possibility.

Earlier this week, the Norwegian Road Federation (OFV) announced that of the 2.8 million private cars that are registered in the country, 754,303 are all-electric compared to 753,905 that run on gasoline.

“This is historic. A milestone few saw coming 10 years ago,” OFV director Øyvind Solberg Thorsen told The Guardian. “The electrification of the fleet of passenger cars is going quickly, and Norway is thereby rapidly moving towards becoming the first country in the world with a passenger car fleet dominated by electric cars.”

This tipping point had been long anticipated, as electric vehicle sales in Norway have massively outpaced gasoline cars for some time. Roughly 85 percent of new vehicles registered in 2024 so far have been zero-emissions, which refers to fully battery-powered vehicles and excludes hybrids.

It’s no secret how the country got here. The Norwegian government has given generous subsidies to promote adoption, including tax rebates that bring the cost of electric vehicles down to similar levels as conventional vehicles, exemptions from some tolls, and an extensive public network of free chargers.

Despite overtaking gasoline-powered cars, electric vehicles are still lagging diesel ones, which account for more than a million of Norway’s existing stock. But the government has an ambitious goal to end the sale of new gasoline and diesel cars by next year, so it may not be long before they catch up.

How easily other countries can mimic their success remains to be seen though—tax exemptions on electric vehicles cost 43 billion kroner ($4.1 billion) in 2023. Norway has been able to pay for this thanks to the country’s massive $1.7 trillion sovereign wealth fund, which, ironically, was built using the profits from its enormous fossil fuel reserves.

Electric vehicle sales have been highly concentrated in three main markets—Europe, the US, and China—accounting for roughly 95 percent of all purchases. In the US, new registrations grew 40 percent last year to hit 1.4 million, while Europe saw a 20 percent increase to 3.2 million.

However, sales have been flagging in recent months, even as production capacity continues to ramp up. This has some worried that concerns around pricing and charging infrastructure could cap consumers’ willingness to make the switch. A brewing trade war over electric vehicles between the West and China also threatens to further dent adoption.

While it might not come cheap, if we’re committed to decarbonizing our transportation system, other governments may need to follow Norway’s lead when it comes to incentivizing cleaner cars.

Image Credit: Emil Dosen / Unsplash

Despite a reputation for being a technology that’s always 20 years away, recent years have seen a flurry of investment as optimism grows that its time may finally have come. According to the Fusion Industry Association, last year’s $900 million in new funding brought the total to $7.1 billion.

That optimism doesn’t seem to have been dampened by major delays to ITER, the international collaboration that has long been considered fusion’s flagship project. Building on the knowledge gleaned from ITER and other publicly funded experiments, a host of startups is now betting they can deliver smaller fusion reactors at a fraction of the time and cost.

But it’s not only the private sector pushing to commercialize the technology. In 2019, the UK government provided £300 million in funding for the design of a novel 200-megawatt reactor known as Spherical Tokamak for Energy Production (STEP). And in a series of papers recently published in the Philosophical Transactions of the Royal Society A, its designers have now given a glimpse of what they’ve come up with.

The most common design for a fusion reactor is known as a tokamak, which heats a cloud of ionized gas, known as plasma, until the atoms fuse together and generate huge amounts of energy in the process. The plasma is contained by incredibly strong magnetic fields generated by coils of magnets wrapped around a doughnut-shaped reactor vessel.

STEP follows similar principles but is tall and narrow, more like a cored apple, according to Science. While that might not seem like much of a difference, it means the distance between the center of the reactor vessel and the magnets wrapping around it is smaller than a classic tokamak.

This reduction in distance makes it possible to use smaller, less expensive magnets to contain the plasma and makes the entire design more compact, according to the Financial Times. The shape of a spherical tokamak also produces an inherently more stable plasma, which should improve performance. However, the design does have trade-offs.

Fusion reactors normally use two isotopes of hydrogen fuel called deuterium and tritium. Tritium is incredibly rare though, so reactors generate their own tritium by way of a reaction between the metal lithium and neutrons released by the fusion reaction. This lithium is stored in tritium breeding blankets wrapped around the chamber, which also act as radiation shields to protect the magnets.

The hole in the center of a tokamak normally houses large magnets and a breeding blanket. But with the narrower design of the spherical tokamak there is much less space, so the STEP reactor will have to do away with the blanket and significantly shrink the magnets, or even do away with some.

Fortunately, new high-temperature superconducting tape, which is also being used by many private startups, could help create more compact magnets. But the reactor will have to generate enough tritium using only the blankets on the outer wall of the chamber, which means the team had to come up with an optimized design using liquid lithium and a vanadium alloy.

The reactor’s designers have also opted for an ambitious architecture with joints in the magnets, which will make it possible to open the top of the vessel. This will significantly speed up maintenance jobs and therefore lower operational costs.

However, project leader Paul Methven, told Science that the recently published designs are still far from being set in stone. And while the project has already found itself a site—a retired coal-fired power station in Nottinghamshire county—the project is currently in discussions with the UK government to secure four more years of funding to come up with a final blueprint.

So, whether or not this reactor ever sees the light of day remains to be seen. But it is encouraging to see government investing significant sums to push the technology forward.

Image Credit: STEP

Today’s largest AI models consume vast amounts of electricity. This is significantly increasing energy bills for the tech firms building these models and making it harder for the companies to live up to ambitious pledges they’ve made to cut carbon emissions.

As a result, these companies are on the hunt for new sources of renewable energy to meet demand without increasing their carbon footprint. Solar and wind power are inevitably the go-to choices, but given the already tight competition for access to renewable power, some tech giants are also looking to emerging technologies.

That’s why Meta recently announced a new partnership with Sage Geosystems. The company’s technology generates carbon-free power by pumping water deep into hot underground rock formations. Under the agreement, the startup will provide up to 150 megawatts of geothermal power to help run Meta’s data centers.

“Sage’s technology marks a significant advancement for the clean energy sector, showcasing the ability to harness geothermal energy virtually anywhere,” Meta said in a press release announcing the deal.

“We’re excited to partner with Sage on a first-of-its-kind project exploring the use of new, advanced geothermal energy in parts of the country where it has not been possible before.”

Geothermal power is an attractive option for data center operators because, unlike other renewable sources like solar and wind, it isn’t intermittent. But conventional plants require access to underground reservoirs of hot water, which only occur in a few areas around the globe with high levels of volcanic activity.

So-called enhanced geothermal technology removes this constraint by doing away with the need for a natural water reservoir. Piggybacking off “fracking” technology developed by the oil and gas industry, the approach involves pumping high-pressure water down into hot, dry rocks to create fractures that can be filled with water. The heated water is then extracted, turned into steam, and used to drive a turbine to generate electricity.

This greatly expands the number of locations in which a geothermal plant can be built. The technology is still nascent, but Sage has already field-tested the approach at an abandoned gas well in Texas and told The Verge that it expects to be able to scale up the approach rapidly because it uses “off-the-shelf” technologies from the oil-and-gas industry.

How soon the technology will make a dent in Meta’s energy bill remains uncertain though. An initial 8-megawatt first phase of the project isn’t expected to come online until 2027. It will then be another couple of years until it’s up to the full capacity of 150 megawatts. And crucially, the companies haven’t actually signed an official power purchase agreement yet, The Verge notes.

The partnership will nonetheless give a boost to a fledgling industry, and Meta isn’t the only big tech player interested. Last year, Google announced that some of its Nevada data centers are being powered by an enhanced geothermal plant built by a startup called Fervo.

Geothermal may face some competition though. Big tech companies are also increasingly looking to nuclear power as a potential source of reliable, carbon-free power. Microsoft, in particular, is interested in developing small modular reactors to help run its data centers.

And there’s still a long road ahead for enhanced geothermal power. A recent report from the Department of Energy estimated that it would take roughly $20 to $25 billion worth of investment to prove the technology and create a self-sustaining industry. That’s doable by 2030, according to the report, but will require continued cost reductions and several large-scale demonstrations to build confidence.

Given the tech industry’s ever increasing energy demands combined with a commitment to lower emissions, these companies could be the most promising route to making that a reality.

Image Credit: Sage Geosystems

The pace of the green transition has been remarkable in recent years, but without careful planning it could quickly grind to a halt. While solar and wind power are now competitive with or even cheaper than fossil fuel plants, they are less reliable because output depends on the sun shining and the wind blowing.

This caps how much renewable capacity we can add to the grid without causing serious stability issues. That is, unless we can find ways to store renewable energy in times of excess so it can help plug the gaps when generation drops off.

And it seems this is starting to happen at pace. According to new data from the EIA, installation of grid-scale batteries accounted for nearly a fifth of new energy capacity installed in the first half of this year, outpacing wind, nuclear, and gas.

Overall, 20 gigawatts of new capacity was added between January and June, and unsurprisingly, solar made up the lion’s share at 12 gigawatts. But batteries, which are counted as power generation because they can dispatch power to the grid, came in second at an impressive 4.2 gigawatts. That dwarfed the 0.4 gigawatts of natural gas power added to the grid in the same period, and pushed batteries above both wind at 2.5 gigawatts and nuclear at 1.1 gigawatts.

Tellingly, the data showed the new battery capacity was heavily concentrated in just four states: California, Texas, Arizona, and Nevada accounted for 93 percent of new installations. Ars Technica notes these states are also deploying large amounts of solar power, which means there’s an increasing need for storage to help meet demand after the sun has gone down.

As well as the data on new installations, the EIA also provided details on retirements of older power plants. While total capacity retired dropped from 9.2 gigawatts in the first half of 2023 to just 5.1 gigawatts in the first half of this year, the mix of retired plants gives a clear indication of the direction the grid is headed, with gas accounting for 53 percent and coal for 41 percent.

The jump in battery installations is a promising sign, as meeting the world’s emission reduction targets will require a massive increase in energy storage deployment. A report from the International Energy Agency earlier this year estimated there needs to be a sixfold increase in capacity globally by the end of the decade to meet 2030 targets set at the COP28 climate talks.

Things are looking promising. Deployments doubled last year, according to the report, and in less than 15 years, costs have fallen by more than 90 percent. Battery manufacturing capacity has also tripled over the past three years.

Meeting the target will still be a challenge though, the report notes. Countries agreed to triple renewable power capacity by 2030, but safely integrating this into grids around the world will require 1,200 gigawatts of new battery storage to be installed as well.

So far, most of this demand is being met by lithium-ion batteries, more commonly found in personal electronics and electric vehicles. But there’s also a host of emerging technologies that could help, including the likes of iron-air batteries.

Altogether, the latest data is a promising signal that grid-scale energy storage is going mainstream. But it will still take a concerted effort to ensure we have enough capacity to support a wholesale shift to renewable power.

Image Credit: ダモ リ / Unsplash

While gas- and coal-powered plants can run night and day, renewable power is highly reliant on the sun shining and the wind blowing. Finding ways to deal with this inherent uncertainty will be crucial if we ever want to fully decarbonize our grids.

One of the most obvious solutions is to store extra energy when conditions are favorable, so it can be fed back into the grid later when renewable production drops off. But building batteries capable of storing grid-scale quantities of electricity presents both engineering and economic challenges.

So far, most grid-storage facilities rely on lithium-ion batteries—the same technology found in cellphones and electric vehicles. But these batteries are relatively expensive and not particularly long-lived. They’re also prone to setting fire, which makes them less than ideal for such projects.

Form Energy is betting that its novel iron-air chemistry, which is specially designed for long-term energy storage, could be the answer. And it’s now set to receive $147 million to build a facility in Maine capable of storing enough energy to provide 85 megawatts of power for up to 100 hours.

“Located at the site of a former paper mill in rural Maine, this iron-air battery system will have the most energy capacity of any battery system announced yet in the world,” Mateo Jaramillo, CEO and cofounder of Form Energy, said in a press release.

The project, which is due to be complete by 2028, is part of a broader package of funding from the Bipartisan Infrastructure Law to upgrade the power grid in the Northeast of the US. Most of the $389 million will be used to expand and upgrade the region’s ability to accept power from large offshore wind farms. But the remainder will be given to Form to build a facility capable of storing 8,500 megawatt-hours of energy.

The key ingredients of the company’s battery cells are iron and water, and they rely on the same process that causes rust to charge and discharge. Energy is stored in the battery by converting iron oxide into pure iron and emitting the oxygen into the atmosphere. To release that energy, the battery absorbs oxygen from ambient air to turn the iron back into iron oxide.

This approach can’t get anywhere close to the energy density of lithium-ion batteries—a crucial consideration when packing batteries into small devices or trying to boost the range of vehicles. But when building large-scale storage systems energy density is much less of a concern than cost, a metric on which iron-air batteries win hands down.

Form says this will allow it to build storage facilities that can act as substitutes for power plants for extended periods. As well as helping to balance the grid during everyday operations, this could also help provide emergency power during extreme weather or other grid outages.

While the Maine project is the most ambitious that Form has announced to date, the company has already announced other smaller pilot projects, and Jaramillo told Canary Media that it’s working on other grid-scale facilities of a similar size that have yet to be publicized.

Given the company is still building the factory that will supply batteries to all these projects, it’s early days for the approach. If all goes according to plan though, it could prove to be a crucial tool in efforts to decarbonize the grid.

Image Credit: Form Energy

Despite the rapid rise of renewable energy, many argue that nuclear power still has an important role to play in the race to decarbonize our supply of electricity. But incidents like Chernobyl and Fukushima have made people understandably wary.

The latest nuclear reactor designs are far safer than those of previous generations, but they still carry the risk of a nuclear meltdown. This refers to when a plant’s cooling system fails, often due to power supplies being cut off, leading to runaway overheating in the core. This can cause an explosion that breaches containment units and spreads radioactive material far and wide.

But now, researchers in China have carried out tests to prove that a new kind of reactor design is essentially impervious to meltdowns. In a paper in Joule, they describe a test in which they cut power to a live nuclear plant—and the plant was able to passively cool itself.

“The responses of nuclear power and temperatures within different reactor structures show that the reactors can be cooled down naturally without active intervention,” the authors write. “The results of the tests manifest the existence of commercial-scale inherent safety for the first time.”

The researchers from Tsinghua University carried out the test on the 200-megawatt High-Temperature Gas-Cooled Reactor Pebble-Bed Module (HTR-PM) in Shandong, which became commercially operational last December. The plant’s novel design replaces the fuel rods found in conventional reactor designs with a large number of “pebbles.” Each of these is a couple of inches across and made up of graphite with a small amount of uranium fuel inside.

The approach significantly reduces the energy density of the reactor’s fuel, making it easier for heat to dissipate naturally if cooling systems fail. Although small prototype reactors have been built in China and Germany, a full-scale demonstration of the technology’s safety had yet to happen.

To put the new reactor to the test, the researchers deliberately cut power to both of the plant’s reactor modules and observed the results. Both modules cooled down naturally without any intervention in roughly 35 hours. The researchers claim this is proof the design is “inherently safe” and should significantly reduce requirements for safety systems in future reactors.

The design does result in power generation costs roughly 20 percent higher than conventional reactors, the researchers admit. But they believe this will come down if and when the technology goes into mass production.

China isn’t the only country building such reactors. American company X-Energy has designed an 80-megawatt pebble-bed reactor called the Xe-100 and is currently waiting for a decision on its license to operate from the Nuclear Regulatory Commission.

However, as New Scientist notes, it’s not possible to retrofit existing plants with this technology, which means the risk of meltdowns from older plants remains. And given the huge amount of time and money it typically takes to build a nuclear power plant, it’s unlikely the technology will make up a significant chunk of the world’s nuclear fleet anytime soon.

But by proving it’s possible to build a meltdown-proof reactor, the researchers have disarmed one of the major arguments against using nuclear power to tackle the climate crisis.

Image Credit: Tsinghua University

While most of the focus on the climate fight has been on cleaning up the electric grid and transportation, a surprisingly large amount of fossil fuel usage goes into industrial heat. As much as 25 percent of global energy consumption goes towards manufacturing glass, steel, and cement.

Electrifying these processes is challenging because it’s difficult to reach the high temperatures required. Solar receivers, which use thousands of sun-tracking mirrors to concentrate energy from the sun, have shown promise as they can hit temperatures of 3,000 C. But they’re very inefficient when processes require temperatures over 1,000 C because much of the energy is radiated back out.

To get around this, researchers from ETH Zurich in Switzerland showed that adding semi-transparent quartz to a solar receiver could trap solar energy at temperatures as high as 1,050 C. That’s hot enough to replace fossil fuels in a range of highly polluting industries, the researchers say.

“Previous research has only managed to demonstrate the thermal-trap effect up to 170 C,” lead researcher Emiliano Casati said in a press release. “Our research showed that solar thermal trapping works not just at low temperatures, but well above 1,000 C. This is crucial to show its potential for real-world industrial applications.”

The researchers used a silicon carbide disk to absorb solar energy but attached a roughly one-foot-long quartz rod to it. Because quartz is semi-transparent, light is able pass through it, but it also readily absorbs heat and prevents it from being radiated back out.

That meant that when the researchers subjected the quartz rod to simulated sunlight equivalent to 136 suns, the solar energy readily passed through to the silicon plate and was then trapped there. This allowed the plate to heat up to 1,050 C, compared to just 600 C at the other end of the rod.

Simulations of the device found that the quartz’s thermal trapping capabilities could significantly boost the efficiency of solar receivers. Adding a quartz rod to a state-of-the-art receiver could boost efficiency from 40 percent to 70 percent when attempting to hit temperatures of 1,200 C. That kind of efficiency gain could drastically reduce the size, and therefore cost, of solar heat installations.

While still just a proof of concept, the simplicity of the approach means it would probably not be too difficult to apply to existing receiver technology. Companies like Heliogen, which is backed by Bill Gates, has already developed solar furnace technology designed to generate the high temperatures required in a wide range of industries.

Casati says the promise is clear, but work remains to be done to prove its commercial feasibility.

“Solar energy is readily available, and the technology is already here,” he says. “To really motivate industry adoption, we need to demonstrate the economic viability and advantages of this technology at scale.”

But the prospect of replacing such a big chunk of our fossil fuel usage with solar power should be motivation enough to bring this technology to fruition.

Image Credit: A new solar trap built by a team of ETH Zurich scientists reaches 1050 C (Device/Casati et al.)

Scientists and policymakers initially resisted proposals to remove CO2 from the atmosphere, due to concerns it could lead to a reduced sense of urgency around emissions reductions. But with progress on that front falling behind schedule, there’s been growing acceptance that carbon capture will be crucial if we want to avoid the worst consequences of climate change.

A variety of approaches, including reforestation, regenerative agriculture, and efforts to lock carbon up in minerals, could play a role. But the approach garnering most of the attention is direct air capture, which relies on large facilities powered by renewable energy to suck CO2 out of the air.

One of the leaders in this space is Swiss company Climeworks, whose Orca plant in Iceland previously held the title for world’s largest. But this week, the company started operations at a new plant called Mammoth that has nearly ten times the capacity. The facility, also in Iceland, will be able to extract 36,000 tons of CO2 a year, which is nearly four times the 10,000 tons a year currently being captured globally.

“Starting operations of our Mammoth plant is another proof point in Climeworks’ scale-up journey to megaton capacity by 2030 and gigaton by 2050,” co-CEO of Climeworks Jan Wurzbacher said in a statement. “Constructing multiple real-world plants in rapid sequences makes Climeworks the most deployed carbon removal company with direct air capture at the core.”

Climeworks plants use fans to suck air into large collector units filled with a material called a sorbent, which absorbs CO2. Once the sorbent is saturated, the collector shuts and is heated to roughly 212 degrees Fahrenheit to release the CO2.

The Mammoth plant will eventually feature 72 of these collector units, though only 12 are currently operational. That’s still more than Orca’s eight units, which allows it to capture roughly 4,000 tons of CO2 a year. Adding an extra level to the stacks of collectors has also reduced land use per ton of CO2 captured, while a new V-shaped configuration improves airflow, boosting performance.

To permanently store the captured carbon, Climeworks has partnered with Icelandic company Carbfix, which has developed a process to inject CO2 dissolved in water deep into porous rock formations made of basalt. Over the course of a couple years, the dissolved CO2 reacts with the rocks to form solid carbonate minerals that are stable for thousands of years.

With the Orca plant, CO2 had to be transported through hundreds of meters of pipeline to Carbfix’s storage site. But Mammoth features two injection wells on-site reducing transportation costs. It also has a new CO2 absorption tower that dissolves the gas in water at lower pressures, reducing energy costs compared to the previous approach.

Climeworks has much bigger ambitions than Mammoth though. The US government has earmarked $3.5 billion to build four direct air capture hubs, each capable of capturing one million tons of CO2 a year, and Climeworks will provide the technology for one of the proposed facilities in Louisiana.

The company says it’s aiming to reach megaton-scale—removing one million tons a year—by 2030 and gigaton-scale—a billion tons a year by 2050. Hopefully, they won’t be the only ones, because climate forecasts suggest we’ll need to be removing 3.5 gigatons of CO2 a year by 2050 to keep warming below 1.5 degrees Celsius.

There’s also little clarity on the economics of the approach. According to Reuters, Climeworks did not reveal how much it costs Mammoth to remove each ton of CO2, though it said it’s targeting $400-600 per ton by 2030 and $200-350 per ton by 2040. And while plants in Iceland can take advantage of abundant, green geothermal energy, it’s less clear what they will rely on elsewhere.

Either way, there’s growing agreement that carbon capture will be an important part of our efforts to tackle climate change. While Mammoth might not make much of a dent in emissions, it’s a promising sign that direct air capture technology is maturing.

Image Credit: Climeworks