How much hydrogen awaits us underground?

地下蕴藏着多少氢能？

In the 1990s, Barbara Sherwood Lollar descended into the Kidd Creek mine in northern Ontario, which cuts more than three kilometers into the ancient root of North America. There her team of geochemists found water that had been confined underground for more than a billion years. 20世纪90年代，芭芭拉·舍伍德·洛拉（Barbara Sherwood Lollar）深入安大略省北部的基德克里克（Kidd Creek）矿井，该矿井深入北美古老地壳超过三公里。在那里，她的地球化学家团队发现了被封存在地下超过十亿年的水。

This ancient brine turned out to be a habitat for living microbes that feed on the hydrogen produced in reactions between the water and the rock. Decades later, Sherwood Lollar, who is a geochemist at the University of Toronto, revisited the team’s hydrogen data to see if there is enough of the gas in the mine to make it a useful source of zero-carbon fuel. “If we can set some smart minds into figuring out how to hook it up and use it, then we’ve got a win for this nascent economy,” she says. 这种古老的卤水竟是微生物的栖息地，这些微生物以水和岩石反应产生的氢气为食。几十年后，多伦多大学的地球化学家舍伍德·洛拉重新审视了团队当年的氢气数据，以评估矿井中的氢气含量是否足以作为一种有用的零碳燃料来源。她说：“如果我们能集思广益，研究出如何收集并利用这些氢气，那么对于这个新兴经济体来说，将是一次巨大的胜利。”

While hydrogen fuel does show promise as a versatile power source, producing it typically generates lots of greenhouse-gas emissions and requires more energy than the gas contains. The ability to tap ready-made underground reservoirs—so-called “geologic hydrogen”—would change the equation. 虽然氢燃料作为一种多功能能源前景广阔，但其生产过程通常会产生大量温室气体，且消耗的能量往往超过氢气本身所含的能量。如果能够开发现成的地下储层——即所谓的“地质氢”，将彻底改变这一局面。

A flurry of exploration efforts have launched to search for the stuff, which is produced underground when water molecules are split by chemical reactions with iron-rich rock or—as they are at Kidd Creek—by the radioactive decay of other elements. The hunt has spread all over the world and engaged dozens of startups, including the Australian firm HyTerra and the Bill Gates–backed company Koloma, which have both been poking around the US Midwest to reach ancient oceanic rocks associated with hydrogen production. 目前，全球掀起了一股寻找地质氢的勘探热潮。地质氢是在地下通过水分子与富铁岩石的化学反应，或像基德克里克矿那样通过其他元素的放射性衰变而产生的。这场搜寻行动已遍及全球，吸引了数十家初创公司参与，包括澳大利亚的HyTerra公司和比尔·盖茨支持的Koloma公司，它们都在美国中西部地区进行勘探，试图触及与氢气生产相关的古老海洋岩石。

Researchers at the US Geological Survey have estimated that trillions of tons of H2 are produced within Earth’s crust; if a small fraction of this could be recovered, it could meet global hydrogen demand for centuries. But the search so far has come up short. No one has yet reported finding a commercially viable reservoir of the gas, and public data on what has been found remains in short supply as companies jockey for position and seek to attract investment. 美国地质调查局的研究人员估计，地球地壳内产生了数万亿吨氢气；如果能回收其中一小部分，就足以满足全球数百年的氢能需求。但目前的搜寻工作尚未取得重大突破。尚无公司报告发现具有商业开采价值的氢气储层，且由于各公司都在争夺市场地位并寻求投资，有关发现的公开数据依然匮乏。

At Kidd Creek mine, Sherwood Lollar and her colleague Oliver Warr leveraged their long-term record of hydrogen to get a fresh read on the potential. By scrutinizing data they’d collected from 35 boreholes at the mine over more than a decade, they found that each one consistently released an average of eight kilograms of hydrogen per year. Extrapolating that finding to the more than 14,000 boreholes at Kidd Creek would mean that around 140 metric tons of the gas is flowing unused out of the mine’s vents each year. 在基德克里克矿，舍伍德·洛拉和同事奥利弗·沃（Oliver Warr）利用他们长期积累的氢气记录，对该矿的潜力进行了重新评估。通过仔细分析十多年来从矿井内35个钻孔收集的数据，他们发现每个钻孔平均每年稳定释放8公斤氢气。将这一发现推算到基德克里克矿的14,000多个钻孔，意味着每年约有140公吨的氢气从矿井通风口白白流失。

This tally, published earlier this year in the journal PNAS, is not a world-changing amount, but Sherwood Lollar says that if all the hydrogen could be captured, it would offer at least a modest source of energy—perhaps enough to power a substantial portion of the mine’s operations. That would be a valuable local demonstration that geologic hydrogen really can be put to use, she says. 这一统计结果于今年早些时候发表在《美国国家科学院院刊》（PNAS）上。虽然这个产量不足以改变世界，但舍伍德·洛拉表示，如果能将这些氢气全部收集起来，至少可以提供一种适度的能源——或许足以支撑矿井运营的很大一部分需求。她说，这将是一个宝贵的局部示范，证明地质氢确实可以被利用。

The results from Kidd Creek add to “the growing evidence that natural hydrogen generation and migration are genuine geological processes,” says Laurent Truche, a geochemist at the University of Grenoble Alpes in France. In 2024, his research team reported that at least 200 metric tons of the gas flow out of the Bulqizë chromium mine in Albania every year. “The remaining challenge is not proving that natural hydrogen exists, but proving that it can be produced economically and reliably at commercial scale,” Truche says. 法国格勒诺布尔-阿尔卑斯大学的地球化学家洛朗·特鲁什（Laurent Truche）表示，基德克里克矿的研究结果进一步证明了“天然氢气的产生和迁移是真实的地质过程”。2024年，他的研究团队报告称，阿尔巴尼亚的布尔奇泽（Bulqizë）铬矿每年至少有200公吨氢气流出。特鲁什说：“目前剩下的挑战不是证明天然氢气的存在，而是证明它能否在商业规模上经济、可靠地生产出来。”

Proof, however, doesn’t necessarily require striking the mother lode. Researchers and startups are also exploring the possibility of stimulating hydrogen production by injecting water, heat, or catalysts into the reactive rocks that naturally produce the gas. More than a dozen of these projects are funded by ARPA-E, which has established a goal of accelerating the hydrogen-producing reaction by a factor of 10,000—the rate at which, researchers estimate, stimulated H2 production would be commercially viable. 然而，证明其可行性并不一定非要找到巨大的矿脉。研究人员和初创公司也在探索通过向天然产氢的活性岩石中注入水、热量或催化剂来刺激氢气生产的可能性。其中十多个项目获得了美国能源部高级研究计划局（ARPA-E）的资助，该机构设定的目标是将产氢反应速度提高10,000倍——研究人员估计，达到这一速率，受激氢气生产才具备商业可行性。

An indication that this could work came earlier this year from the mountains of Oman, where a team drilled a one-kilometer borehole and injected 50,000 cubic meters of water into the rock. When they opened the well several months later, gas was spewing out—and it was 90% hydrogen. “It’s bubbling with gas,” Jo Shannon, a geoscientist at the University of Southampton in the UK, told attendees of the European Geosciences Union conference in May. (Shannon declined to comment beyond what was presented.) 今年早些时候，阿曼山区传来的消息显示这种方法可能奏效：一个研究团队钻了一个一公里深的钻孔，并向岩石中注入了50,000立方米的水。几个月后，当他们打开井口时，气体喷涌而出，其中90%是氢气。英国南安普顿大学的地球科学家乔·香农（Jo Shannon）在5月的欧洲地球科学联盟会议上告诉与会者：“那里冒着气泡。”（香农拒绝就演示内容之外的问题发表评论。）

While Shannon said this was a promising sign, she was careful to add that a slew of unknowns remain. The most crucial question is a basic one: Is the hydrogen rising up out of the well made through stimulation, or had it been there all along? 虽然香农表示这是一个积极的信号，但她谨慎地补充说，仍有许多未知数。最关键的问题是一个基本问题：从井中涌出的氢气是通过刺激产生的，还是它一直就在那里？