Why stop MACH2?
Hydrogen is an extremely flammable, costly, and inefficient fuel source. The production and use of hydrogen gas emits toxic and greenhouse gasses and poses a threat to our communities and our climate. Any potential benefits of hydrogen gas and the MACH2 project are far outweighed by the dangers they pose.
Dangers of hydrogen gas
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Hydrogen gas is extremely explosive and flammable, much more than methane (natural gas/fossil gas/fracked gas). Methane will combust over a narrow range of concentration: from 5% to 15% in air. Hydrogen gas, on the other hand, will combust over a much wider range of concentration—from 4% to 77% in air. This means that it doesn’t take much oxygen to make hydrogen dangerous. Hydrogen ignites easily: a spark of static electricity from clothing is enough to set it off. Hydrogen is odorless (and an odor can’t be added to it, as is done with methane), and its flames are colorless making them hard to see. All of this danger requires specialized training and equipment for workers and first responders.
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Because the hydrogen gas molecule is so small, it can escape through the tiniest gaps and cracks in valves, fittings and pipes. Equipment and appliances made for methane (natural gas) are not adequate for carrying hydrogen gas, so retrofitting or complete replacement would be required. For example, the ubiquitous cone-and-thread valve used in natural gas systems runs a high risk of leaking hydrogen gas. If hydrogen were blended into home heating and cooking gas, homeowners would need to replace their appliances, like stoves, water heaters, and furnaces. The existing fossil fuel infrastructure that moves natural gas across the landscape and through communities would have to be retrofitted at great expense to carry hydrogen gas. When methane leaks—which happens often—we can detect it by smell due to an additive that gives it an odor. But no such additives are available for hydrogen gas, so leaks won’t be detected by workers or homeowners.
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Hydrogen gas seeps into and reacts with materials to make them brittle, causing metal pipes, fittings and valves to crack. For this reason, expensive different or specially-treated materials are required for transporting hydrogen gas over those traditionally used with methane/natural gas/LNG. Hydrogen gas can then escape through the cracks into the surrounding area, including buildings, industrial facilities, and homes. This leakage vastly increases the risk of explosions and fires, because just a small spark can be enough to ignite hydrogen gas in air. This danger increases the expense of any machinery, appliances, or vehicles that involve hydrogen because its materials can’t be “off the shelf” but must be specially engineered for use with hydrogen gas.
Why MACH2 won’t work
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Making hydrogen gas requires a lot of energy, using either electricity or fossil fuels. For vehicles, hydrogen requires several times more energy than electric when measured “well to wheel.” In fact, the inefficiency of hydrogen gas as a fuel may very well be part of its benefit to fossil fuel and other companies that stand to profit from its production: it takes a lot more fossil fuels to make hydrogen gas than the amount of fossil fuels needed to do the same amount of work. The same is true with making hydrogen from water by electrolysis: it would be far more efficient to use that electricity directly—in vehicles, home heating and cooking, and to run motors of all kinds—rather than hydrogen gas that had been made by electrolysis. Additionally, blending hydrogen with methane/natural gas and burning them together is also inefficient because the amount of methane saved in this trick is far outweighed by the amount of greenhouse gasses produced making and burning the hydrogen gas.
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In addition to being an inefficient fuel, hydrogen gas also requires specially engineered pipes and equipment to prevent leaks and cracking. Specialized safety training is needed for workers and first responders. Hydrogen gas has a low energy density, meaning it takes up a lot of room for the amount of energy it delivers compared to methane/natural gas/LNG. To increase its energy density, hydrogen gas is compressed or super-cooled, its temperature lowered below that needed to make liquified natural gas (LNG). Lowering the temperature requires lots more energy. This compression of hydrogen gas in pipes and storage tanks is needed to make it more cost effective to transport and store, but further increases the risk of dangerous leaks.
To make hydrogen gas production carbon-free, nearly all of the carbon dioxide (CO2) must be captured and kept out of the atmosphere. The methods proposed are carbon capture and storage (CCS) and carbon capture utilization and storage (CCUS, which takes liquid CO2 back to the fields to extract more fossil fuels). Despite this technology being decades old, it still is not yet worked at the scale and efficiency required for the job. In other words, it remains science fiction to capture even close to 90% the CO2 produced when making hydrogen gas. Even if that new technology works in real life, its development will take time, costing millions or billions of dollars more, further raising the cost of making hydrogen gas, a cost that may very well be borne largely by taxpayers. In reality, it will be most cost-effective for businesses to just release CO2 into the atmosphere, eliminating any claim of ‘green’ from the hydrogen production.
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Leaks, explosions, and fires. Leaks can’t be detected by smell. The explosiveness of hydrogen gas is far greater than for methane. Hydrogen flames are invisible. When it is burned, hydrogen gas promotes the formation of nitrogen oxides (NOx), which are toxic components of smog and greenhouse gasses. Several studies have shown that the US government has underestimated the amount of leaks and other dangers posed by hydrogen gas production on a large scale. The industry uses those estimates in their plans.
But the gravest danger we face from hydrogen gas is its contribution to an already heating climate. Even to qualify for the label ‘clean,’ the federal government allows 4 times as much CO2 released for every unit of hydrogen gas made, so not so ‘clean and green’ after all. Hydrogen gas itself is an indirect greenhouse gas: when it enters the atmosphere, it prolongs the buildup of methane, a potent greenhouse gas, many times more heat-trapping than CO2. It does this by interacting with another compound, hydroxyl radicals (OH), preventing them from depleting the methane. That causes methane to last for years in the atmosphere, trapping more heat on Earth. Further global heating is the real danger of producing lots of hydrogen from hubs like MACH2.
What if MACH2 gets built
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Producing hydrogen gas is energy intensive. It doesn’t make financial sense to use electrolysis (with nuclear power, wind or solar) on a large scale. The only financially sensible way to make hydrogen is using fossil fuels. But because effective carbon capture is an unfinished technology—and there is no regulation to ensure it will actually happen—using fossil fuels to make hydrogen will not get us off fossil fuels, abate greenhouse gas emissions, or decarbonize the economy. Decarbonizing the economy is the expressed intent of the Infrastructure Act which will fund the hydrogen hubs. The Earth is already experiencing dangerous levels of heating and we’re locked into further heating in the coming decades. We must stop using fossil fuels in every way possible as soon as possible. Hydrogen production anywhere—especially on the scale of the hydrogen hubs like MACH2—only makes this problem worse.
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MACH2 plans to combust hydrogen gas in power plants and heavy industry processes. Any combustion of hydrogen gas in air produces nitrous oxides (NOx) which are direct greenhouse gasses. Hydrogen itself is an indirect greenhouse gas that increases the global heating caused by methane, which is many times more potent than CO2 in trapping heat. All the hydrogen gas that leaks—and much will leak during production, transport, and use—will increase the lifetime of methane in the Earth’s atmosphere and increase the planet’s warming.
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Hydrogen gas is odorless, and odors can’t be added to it as is done with natural gas, so we won’t be able to smell it when it leaks. The flames of burning hydrogen gas are invisible, so we won’t be able to see it when it starts to burn. The dangers hydrogen gas poses to workers and first responders will require that everyone receive special equipment and extensive training. The explosions and fires caused by the manufacture, transport, and end-use of hydrogen gas will raise questions whether any benefits to certain industries are worth it, when there are many more sensible alternatives.
In 2023, a prototype hydrogen bus exploded and caused a fire at a hydrogen gas fueling station in California. Like SEPTA in our region, the local transportation authority was testing a few hydrogen buses to see if they would compare favorably and be worth the investment. The fire damaged the hydrogen fueling station, taking all of their 10 prototype buses out of commission. The likelihood of such catastrophes only increases with the number of such uses. If we already had an explosion with one test bus, once hundreds of such buses hit the roads, we will undoubtedly have more.
Add to this the unique danger of carbon capture (called Carbon Capture and Storage or CCS and Carbon Capture Utilization and Storage or CCUS). Piping underground massive amounts of captured CO2 poses an enormous risk across a wide geographic area, from the hydrogen production facilities, through densely populated areas, out to the fracking fields: If CO2 were to begin pouring out at any point, the heavier-than-air CO2 would roll across the landscape, smothering all people and animals in its path.