Climate and energy

While working as a drilling engineer in the shale fields of southern Texas, Tim Latimer, 34, came to a realization: The same technical advances that sparked the natural gas fracking boom could change the game for geothermal energy.

Geothermal power plants generate carbon-free electricity around the clock by circulating water through hot rocks in the Earth’s crust. But the sector has historically only been able to develop affordable facilities in areas with porous, permeable, high-temperature rock formations at relatively low depths. 

A half-century ago, Los Alamos National Lab researchers demonstrated that humans could engineer around some of these geological constraints by cracking underground formations around Fenton Hill, New Mexico, to create the permeability necessary to allow water to flow freely. But creating such wells, known as enhanced geothermal systems, would remain too tricky and expensive to commercialize for decades.  

Latimer recognized that the natural gas sector’s success in driving down the cost of horizontal drilling and hydraulic fracturing, which uses high-pressure fluids to fracture rock, could change all that. If so, it meant companies could develop geothermal power in many more places, helping to deliver far more of a crucial component largely missing from the electricity grid: a steady form of clean power that can fill in the gaps as wind and solar sources fluctuate throughout the day and year, reducing the need for coal and gas plants.

During his MBA studies at Stanford, Latimer met Jack Norbeck, who had closely analyzed the Los Alamos experiments for his PhD work and come to a similar conclusion. Together, they formed Fervo Energy in 2017. The pair quickly earned a spot in the inaugural class of Cyclotron Road, a US Department of Energy-backed entrepreneur fellowship program, and soon after secured funding from Bill Gates’s Breakthrough Energy Ventures.

Under Latimer’s leadership as CEO, Fervo has been on a roll. Last summer, the startup said initial tests demonstrated that its first set of wells developed with these techniques, near Winnemucca, Nevada, are commercially viable. Those wells are now sending up to 3.5 megawatts of electricity onto the state’s grid (enough to power roughly 3,500 homes), most of which Google has purchased to run its operations around Las Vegas. 

Last fall, Fervo also began developing Project Cape, a geothermal power plant in Utah that will generate up to 400 megawatts, most of which will power homes and businesses in Southern California. And this summer, the company announced it’s developing another geothermal plant in Nevada as part of a partnership with Google and the state’s main utility, NV Energy.

Today, nearly all electronics and electric vehicles are powered by lithium-ion batteries. They work by shuttling charged particles, or ions, between a metal cathode and an anode typically made of graphite. Researchers have known for decades that an anode made from lithium, the lightest metal on the periodic table, could enable a rechargeable battery to store significantly more energy relative to its size. But lithium is highly reactive: Interactions with the battery’s electrolyte, which usually consists of a salt dissolved in a volatile liquid solvent, make lithium metal batteries more prone to catching fire. Researchers have sought to overcome this hazard by replacing liquid electrolytes with solids, but that reduces  performance.

Chibueze Amanchukwu, 31, developed a new type of electrolyte that’s a liquid when the battery is in use and is free of any fire-causing solvents. The process involved months of testing different combinations of salts to find a concoction with a low enough melting point. His team’s electrolyte, made from a mix of lithium, potassium, and cesium, melts at 45 °C—meaning it could work in batteries built to power EVs or to store grid electricity. The researchers are now working to push that temperature as close to 0 °C as possible.

The technology, Amanchukwu says, is not quite ready for commercialization. But it marks a major step toward what he calls the “elusive dream” of making lithium metal chemistry work. “What our work shows is that you can have batteries with high energy density and high performance, without sacrificing safety,” he says.

Xiangkun (Elvis) Cao, 32, wants to make air travel carbon-neutral. He’s created a device that mimics photosynthesis and turns carbon dioxide into airplane fuel. 

Air travel makes up 2% of global carbon emissions, according to the International Energy Agency. Artificial photosynthesis, whereby scientists combine light, carbon dioxide, and water in a reactor to create synthetic fuel, has shown promise as a decarbonization tool. But researchers have struggled to make the technology scalable, low-cost, and efficient.  

Using a photocatalytic reactor to convert CO₂ into useful chemicals is not new, but Cao’s reactor stands out. Its efficient delivery of light, hydrogen, CO₂, and heat is a feat of interdisciplinary engineering. Drawing from the field of optics, Cao uses a waveguide, which focuses light onto the area where the reaction takes place. At the same time, a special panel called a baffle (used in everything from household stoves to rocket engines) efficiently mixes CO₂ and hydrogen. To keep the reactor at the ideal temperature, phase-change materials emit and absorb heat as they solidify and melt. 

His device converts about half of the CO₂ it absorbs into carbon monoxide, a percentage 20 times higher than similar reactors. The carbon monoxide is then mixed with hydrogen to make an essential jet fuel ingredient.  

United Airlines has agreed to purchase 300 million gallons of synthetic fuel from the spinoff based on his technology, over the next 20 years. The flights powered by these fuels will still emit carbon dioxide, which makes them carbon-neutral but not carbon-negative. 

Cao, who completed his PhD in mechanical engineering at Cornell, hopes to someday design a device that could be attached directly behind a plane’s exhaust pipes. There, the device could convert emitted CO₂ into fuel in real time, preventing the greenhouse gas from ever entering the atmosphere.

This post has been updated. 

Cement is one of the most widely used materials on the planet. Producing it is a massive problem for climate change, making up roughly 7% of global greenhouse gas emissions.

Cody Finke, 34, cofounded a company called Brimstone that’s trying to clean up the cement industry by making the familiar material in a new way.

Today the most popular type of cement is a variety called Portland cement. The material is formed by heating up a mixture containing limestone, which kicks off chemical reactions that release carbon dioxide. To avoid spewing out that greenhouse gas, Finke figured out how to make Portland cement with silicate rocks instead.

Brimstone’s process still requires heating kilns to high temperatures, which can be energy-intensive and produce emissions no matter which ingredients are involved. But the company’s final product will have properties identical to the cement used in industry today, and if renewable energy is used to heat the kilns, the company’s products could be entirely emissions-free, Finke says.

Making Portland cement was a major focus during development, he adds, because customers might consider novel materials too risky to use in big, expensive projects. Another priority was making a material that could compete on cost, a distinction the company hopes to prove when it begins producing its material at a large plant.

Finke cofounded Brimstone in 2019 and now serves as CEO. In March 2024, the company received a $189 million grant from the US Department of Energy to scale up cement production. Brimstone plans to use the funding to build its first commercial plant—which could eventually produce as much as 140,000 metric tons of cement and other co-products per year.

Cement production generates roughly the same amount of emissions globally as passenger vehicles, but the industry tends to get less attention and funding from investors, Finke says. Cement may not strike most people as an urgent climate challenge, but as he puts it, “Anyone who cares about climate should also care about cement.”

After decades of dithering on climate change, nations now need to radically cut greenhouse gas emissions and find ways to suck down vast amounts of carbon dioxide already in the atmosphere.

In fact, studies show that the world may need to remove and safely store billions of tons of it per year by midcentury to keep global warming in check—or pull the planet back to a safer state.

Noah McQueen, 28, cofounded Heirloom Carbon Technologies in 2020 in a bid to drive down the costs and scale up the facilities needed to do that. 

As an undergraduate at the Colorado School of Mines, McQueen had been searching for ways to use their love of math and science to achieve “an impact that’s bigger than myself.” When they began working with Jennifer Wilcox, a chemical engineering professor who had done pioneering work on capturing carbon dioxide from industrial plants or plucking it out of the air, McQueen finally saw a way to do so.

In the years that followed, McQueen helped develop an approach to carbon removal they believe will prove effective and affordable, inspired by the natural rock weathering process that already draws down at least half a billion tons of carbon dioxide a year.

The trick is to do that far faster than nature. Heirloom heats crushed limestone to release carbon dioxide, then adds water to what’s left to form calcium hydroxide, which is basically a carbon dioxide sponge. The company stacks thin layers of the material in trays exposed to the air, which react with the greenhouse gas within days, forming limestone once again. And then the process begins anew.

Heirloom intends to inject most of the resulting stream of carbon dioxide into deep wells, where it should remain permanently sequestered. But some will go into products, like concrete, that should keep the gas out of the atmosphere for decades.

The company, which has raised tens of millions of dollars in venture capital, is operating a plant in California that removes 1,000 tons of carbon dioxide per year. It’s also building two plants in Louisiana that will be capable of removing and storing 320,000 tons annually. Heirloom secured funds under the Department of Energy’s direct-air-capture hubs program for the larger one. 

The company has distinguished itself from some of its peers by refusing to use the removed carbon dioxide for enhanced oil recovery, which helps free up additional fossil fuels from wells, or to accept money from the oil and the gas sector. 

Heirloom plans to continue developing facilities and hopes to remove and sequester a billion tons of carbon dioxide from the air by 2035. As the process improves along the way, McQueen believes their approach could prove to be one of the most cost effective ways of doing so.

Direct air capture technology has made it possible to remove carbon dioxide from the sky. But then what? Claire Nelson, 31, cofounder of Cella Mineral Storage, aims to inject that carbon dioxide underground and securely store it as a mineral called carbonate. 

Carbon mineralization naturally occurs when carbon dioxide, water, and porous volcanic rock meet. Cella tweaks this process by repeatedly injecting CO₂, followed by water, into bedrock. This allows the company to more evenly distribute CO₂ within the rock’s pores and use half as much water as other similar carbon storage methods. Using fewer resources lowers the cost, and a more even distribution of carbonate makes it less likely the rock’s pores will clog up. Plus, injection sites don’t need to be monitored as heavily, because there’s little risk of the carbon dioxide escaping. 

Nelson, who received her PhD in geochemistry from Northwestern University, is also working to accurately capture where mineralized carbon is stored underground. She’s filed a patent for a technique that  will analyze the levels of carbon and calcium in the water contained within a reservoir at different stages of the mineralization process. With this technique, the company can determine where exactly in the reservoir the carbon is being stored. 

Cella, which is based in New York City and employs seven people, is now constructing its first commercial carbon storage facility, in Kenya, alongside a direct air capture plant built by RepAir. They will need to show that the stored carbonate does not clog the reservoir’s pores and reduce the rock’s permeability (which could be  detrimental). Then, Nelson hopes to expand to more countries and plans to focus her efforts on those that will struggle the most to transition from fossil fuels to renewable energy.

Roughly 30% of global greenhouse gas emissions come from industrial processes in factories that make the things we use in our daily lives. Most of the energy that sector consumes is in the form of heat, and nearly all of that heat is generated from burning fossil fuels.

Wind and solar power might be able to help, but to date they haven’t been feasible solutions because they’re not available all the time, whereas factories can run 24/7. Andrew Ponec, 31, aims to bridge that gap. As cofounder and CEO of Antora Energy, he’s working to create thermal batteries that can take in cheap, low-emissions electricity when it’s available and store it as heat to disperse later.

Antora’s technology works by running electricity through carbon blocks—resistive heating warms the blocks up to temperatures over 2,000 °C (3,632 °F). That heat can then be applied in industrial processes, like those used to make food and paper. Antora plans to someday use a technology called thermophotovoltaic cells to turn the heat back into electricity for customers who want other ways to use the stored energy.  

Ponec and his cofounders set out to reduce emissions as much as possible, so they focused on cleaning up heavy industry—a sector that needs a lot of help. They explored other tools, including rail electrification, mining technology, and a range of batteries, but eventually landed on thermal energy storage, starting Antora in 2018.

The company is now building out its California factory to produce more thermal batteries for customers. Antora recently raised $150 million from investors and received a $14.5 million grant from a US Department of Energy agency.

While cleaning up transportation or agriculture might be more top of mind for most people, addressing heavy industry and other behind-the-scenes sectors is a crucial part of climate action, Ponec says: “We have the opportunity to eliminate a huge amount of carbon emissions.”