The 2024 Paris Olympic Games are rapidly approaching, and sustainability is a core part of these games. This shouldn’t be surprising, as France is one of Europe’s most active pro-climate countries. However, a group of engineers and scientists have found a worrying flaw in the Olympics’s sustainability push. You see, Toyota is a partner to the games and has supplied them with 1150 EVs, most likely their brilliant bZ4X and 500 hydrogen fuel cell Mirais, in a PR push to help the games reach net zero. Sounds good, right? Well, when you dig into it, the fact that a hydrogen car is being advertised as net zero is worrying. As such, this group of engineers and scientists have penned a letter to the Paris Olympics to drop the Mirai. So, why are hydrogen cars incompatible with net zero?
Well, in this open letter, the 120 engineers and scientists said, “We are writing to express our concern that Toyota’s promotion of a hydrogen car is scientifically misaligned with net zero and will damage the reputation of the 2024 Games.” It went on to point out that “The IPCC (Intergovernmental Panel on Climate Change) is clear that battery electric vehicles represent the most effective way to decarbonise passenger transport” and that “Hydrogen used to power road transport is not aligned with the world’s net-zero goals and ultimately risks distracting and delaying from the real solutions we have available today.”
But hydrogen vehicles produce no emissions, right? They react hydrogen with oxygen to make energy, which only produces water.
Well, yes, but that is only half the equation. After all, where do you get the hydrogen?
Ideally, hydrogen vehicles would run off green hydrogen. This is hydrogen produced from renewable energy and, therefore, has the lowest carbon emissions of any source of hydrogen. But green hydrogen has a serious problem. Efficiency.
Making hydrogen through electrolysis (as green hydrogen is) is, at most, 75% efficient. Hydrogen fuel cells are at most 40% efficient. As such, you can only get 0.45 kWh of useful energy back out for every kWh of renewable energy used to make green hydrogen. In other words, green hydrogen wastes 55% of the energy used to make it! To top this off, the electrolysis machines, as well as the storage and transportation, are incredibly expensive. As such, not only is green hydrogen one of the most expensive forms of energy we have, but adopting it also effectively slows down our energy transition, as it requires us to build far more renewable infrastructure to meet the same demand.
But, there is a far cheaper form of hydrogen known as grey hydrogen. This is made by converting natural gas into carbon dioxide and hydrogen. Sometimes, this carbon dioxide is captured and repurposed, but mostly, it isn’t. But, over 95% of the hydrogen we currently produce is grey hydrogen.
This is a huge problem, as grey hydrogen produces around 13.7 kg of carbon emissions per kg of hydrogen produced. Now, each kg of hydrogen produces 33 kWh of energy, meaning grey hydrogen produces 415 grams of carbon emissions per kWh. In other words, it has only slightly less emissions per unit energy than the cleanest coal plants! But the Mirai has a tank that can hold 5.6 kg of hydrogen to drive 402 miles. If you do the maths, this means the Mirai actually causes 190 grams of carbon emissions per mile driven. Only slightly less than the 195 grams of emissions per mile of Toyota’s petrol/gasoline-powered Camry.
In other words, this ‘net zero’ car is actually as bad for the environment as an equivalent fossil fuel vehicle!
But don’t electric vehicles suffer the same issue? Their energy is produced by coal plants and gas plants, after all. They aren’t net zero.
This is true, but they are far more efficient at using renewable energy, as the round-trip efficiency is over 80%.
But, our modern energy grids are much cleaner than you might think, especially in France, where the main energy source is nuclear (66.6%), with renewables taking second place (27%). As such, the average emissions of French energy is only 39g of carbon emissions per kWh. In other words, even the least efficient battery-electric vehicles, being charged in France, will cause a quarter of the emissions of the Mirai per mile driven.
Unless green hydrogen can solve its massive efficiency and cost issues, hydrogen vehicles won’t be a viable solution. It’s time we let go of the hydrogen daydream and embrace battery-electric vehicles. They are simply better, and are getting significantly better, and cleaner, with every year that passes.
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Sources: Car Expert, GH2, Idealhy, Will Lockett, Now Tricity, Fuel Economy, MAN