How the U.S. Military can switch to synthetic fuels and help save the world INTERESTING ENGINEERING - JUNE 16, 2022 With heightened tensions amid the Russia-Ukraine conflict, it's tempting to accept a triage-like attitude to global crises, letting some slip into blind spots while society deals with what seems most pressing. But the U.S. military — a necessity for sovereign protection in the event of open war with other nations — already harms our planet's habitability, and this will only be exacerbated by the ravages of war on the global environment. "The U.S. military uses about 2 billion gallons of natural gas per year," said President Kenneth Agee of Emerging Fuels Technology, in an interview with IE. "In support of a remote conflict, about 70 percent of the military’s tonnage is hauling fuel." In fact, militaries are among the largest sources of emissions in the world. Combined, the armed forces of all nations could be generating about six percent of all greenhouse gas emissions, according to estimates by the United Kingdom's Scientists for Global Responsibility. It's very unlikely that any one person or nation has enough power to prevent conflicts or even to scale down the military-industrial complex to more sustainable levels. However, in lieu of a direct solution, there may be other ways to reduce the levels of greenhouse gas emissions — not only for industries, but for the U.S. military, and other nations as well. While U.S. aircraft carriers and submarines are already nuclear powered, converting other hardware to renewable fuels would require drastic changes to the logistical structure of the militaries of the world — which have spent decades and centuries honing the art of war. During a time of mounting tension, armed forces probably don't place a big priority on developing sustainable environmental policies. The question, then, is raised: what else can we do to make global militaries more sustainable? Portability and flexibility are crucial to introducing renewable fuels into military use A "large loophole" in the Paris agreement lets governments off the hook when it comes to reporting the greenhouse gases created by their militaries. According to a report from the Guardian, under the earlier climate agreement — the Kyoto protocol — world militaries were also given a pass, exempting them from needing to meet CO2 targets. In fact, the Paris Agreement makes it voluntary, not mandatory, for nations to include their armed forces in their carbon-cutting requirements. And the potential for more nations and regions being sucked into the current conflict acts as a reminder that conflict can occur at any time, meaning there isn't much incentive for drastic changes in operations. But there might be another way — one that avoids the need to execute a complete overhaul of not only the combustion engines and jets of military hardware, but also the complex lines of supply and logistics that militaries rely on during both conflict and peacetime. "Production of renewable fuels can be looked at as having more portability and flexibility in terms of how you move the fuel because the renewable fuels production plants will be much smaller than a typical refinery and could be located closer to the end-user," explained Agee. By "end-user," Agee means consumers — in the context of defense spending, that would be the many vehicles, craft, and aircraft of the military. US military used roughly 1.7 million barrels of jet fuel per day in 2019 "Renewable fuels could offer operating flexibility," said Agee. "In the last few years, we've seen the emergence of 'e-fuels,' converting CO2 into CO and splitting water to make hydrogen. You can take water and CO2 out of the atmosphere — direct-air capture can drive air through fans that absorb CO2 from the atmosphere." Specialists could build modules that extract moisture and CO2 from the atmosphere, at the beginning of a process to generate e-fuel. This would require electricity, "but there are many ways to do that," explained Agee. "You can convert the CO2 and water into CO and hydrogen, which can then be turned into synthetic hydrocarbons." And hydrocarbons can be refined into both diesel and jet fuel. This is crucial because the total demand for jet fuel in the U.S. "was roughly 1.7 million barrels per day in 2019," said Agee. "And it's currently returning to about that level — 8 million barrels per day, worldwide." Agee thinks the future will lead to most companies blending synthetic solutions via conventional jet fuel. In fact, militaries are among the largest sources of emissions in the world. Combined, the armed forces of all nations could be generating about six percent of all greenhouse gas emissions, according to estimates by the United Kingdom's Scientists for Global Responsibility. Taking synthetic e-fuel to the mainstream "But I think it's going to grow rapidly over the next decade — and, as more and more of these methods to create different combinations emerge, it should gain more momentum," added Agee. To get there, the U.S. military would have to replace all the conventional jet fuel with renewable jet fuel — that's a big ask. "Currently most synthetic jet fuel is limited to a 50 percent blend with conventional jet fuel," explained Agee. "There are logistic issues to develop ways to implement the blends and certify the finished fuels." This will require that industry and military forces work in tandem to problem-solve and produce synthetic fuels that can be used at a 100 percent concentration in modern vehicles. But prospective sustainable e-fuel systems will face more obstacles than just the science, alone. "Everything is so established in the manufacturing and supplying logistics of jet fuel, those challenges have to be tackled to get synthetic fuel to become the mainstream," said Agee. Scaling synthetic fuel for wartime and commercial end-users It might be the case that each source of carbon-emitting fuel will need its own unique solution. "We also have to replace petrochemicals that come from petroleum as well," added Agee. "the project [our firm] did with the company Twelve is a good example, they had a contract with the military to show they could convert CO2 to jet fuel." "Basically, they modified electrolysis with a catalyst, and can convert CO2 to CO," said Agee. "Of course, CO2 is hard to do anything with, but CO is a reactive component and used in our process. Twelve delivered CO in cylinders to us, when we ran it through our reactors to make synthetic crude, and then upgraded that to make jet fuel." In fact, to demonstrate this ability, one can begin with CO2 and go backward: "take some electricity to push the molecules back up a hill (if you will), and turn them back into a fuel." To scale this process, larger plants are needed "to make commercial quantities of synthetic e-fuels," said Agee. High wartime emissions - Paramount in the drive to develop synthetic, renewable fuel capable of powering highly advanced military vehicles is performance. "I think that as it becomes progressively more available, renewable fuel will become more ubiquitous," said Agee. "But it has to function just as well as the petroleum equivalent. The energy content has to be the same, physical properties have to meet the same specs." This will take time, but the benefits far outweigh the drawbacks — and with no end in sight to the potential for conflict, there is no time to waste in minimizing the effects of wartime industry developments and military deployments on the Earth's precious habitability.

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