The world is undergoing an energy transition to reduce CO2 emissions and mitigate climate change. The COVID-19 pandemic and the Russia-Ukraine war have further increased the interest of Europe and Western countries to invest in the hydrogen economy as an alternative to fossil fuels. Hydrogen can significantly reduce geopolitical risks if the diversity of future hydrogen energy suppliers is increased.
Hydrogen is a particularly challenging product to transport safely. One option is to liquefy hydrogen, which requires cooling to 20 Kelvin (-253 °C). This is an expensive process and requires around 30% of the energy stored within the hydrogen.
A pioneering approach developed by IIASA researchers and colleagues proposes solid air (nitrogen or oxygen) as a medium for recycling cooling energy across the hydrogen liquefaction supply chain. At standard temperature and pressure, air is a gas, but under certain conditions, it can become a liquid or solid. Solid Air Hydrogen Liquefaction (SAHL) consists of storing the cooling energy from the regasification of hydrogen, by solidifying air, and transporting the solid air back to where the hydrogen was liquefied. The solid air is then used to reduce the energy consumption for liquefying hydrogen. The process is divided into four main steps: hydrogen regasification, solid air transportation, hydrogen liquefaction, and liquid hydrogen transportation.
[...] In their paper, the authors also address the ongoing debate in industry and academia to find the best alternative to transport hydrogen by sea:
"Compared to ammonia or methanol, liquefied hydrogen is the best option for several reasons. Transporting hydrogen with ammonia and other molecules would require around 30% of the energy transported to extract the hydrogen. The hydrogen is liquefied where electricity is cheap. Also, SAHL can lower energy consumption for hydrogen liquefaction by 25 to 50%," Hunt concludes.
Journal Reference:
Hunt, J., Montanari, P., Hummes D., et al. (2023). Solid air hydrogen liquefaction, the missing link of the hydrogen economy. International Journal of Hydrogen Energy DOI: https://doi.org/10.1016/j.ijhydene.2023.03.405
(Score: 5, Interesting) by MrGuy on Tuesday May 23 2023, @03:40PM
Let’s ignore the storage vs source of energy debate for a minute, and accept we’re using some renewable source like solar to generate the hydrogen.
Hydrogen still have 2 major weaknesses:
* Production loss
* Energy density
This article addresses some of the first concern. Even then, it doesn’t solve it. There’s a reason flywheels, pumped hydro, and huge batteries are still the tool of choice for storing excess energy in the electric grid vs hydrogen. Hydrogen production is lossy from cooling, and that’s not even taking into account the cost to produce and safely store cryogenic fluids (non-trivial).
The other big concern for hydrogen is energy density, which is hard to get around. Hydrogen has about 1/8th the energy density of octane when burned. This means even if you had cheap liquid hydrogen, and you solved all the thermal issues, you couldn’t just spray it into your V8 engine and burn it. You’d get 1/8th the power from the same engine displacement. You’d need an engine 8x the size, so twice as wide, long, deep. Which would be heavy. Or you’d need to make do with much less power. Or, more likely, you’d devise an alternate drivetrain, where you use a fuel cell to directly power electric motors or charge an EV’s batteries as you go (albeit not as fast as they’re drained by the motors) But one way or another, you’re simply hauling around less “liquid energy,” which would be a problem for most of the ways modern humans use motor vehicles.
I’m skeptical of the “hydrogen economy” simply because I hear it touted as a drop-in replacement for fossil fuels, and it’s not.