B . L O G

I see a lot of hydrogen in the news lately, all related to green future. There's the zero-emission house in Italy powered solely by hydrogen fuel cells, the world's first train powered by hydrogen fuel cells, a diesel engine modified to run on 90% hydrogen, etc. This is all marketed as zero-emission or nearly zero-emission. But that's simply very far from truth. Yes, there are no CO₂ emissions during hydrogen combustion but there are generally lots of emissions during its production today and even combustion is not as benign as it seems. Emissions during combustion The claims of zero-emissions during combustion are not entirely true. Burning of hydrogen emits water vapor, in fact, 2.6 times more water vapor than burning kerosene. Water vapor is a potent greenhouse gas with major influence on climate change. The lifetime of water vapor in the atmosphere is, however, much lower (from a couple of days up to a year), compared to CO₂ lifetime of about 100 years. But the water is also cycling faster - if water that falls as rain quickly evaporates then its lifetime in atmosphere can be effectively much longer. However, it seems this is still not considered a problem, probably because clouds of water vapor generally form below the stratosphere where water vapor cannot accumulate with no accumulation of non-condensable gases (at atmospheric pressure/temperature) such as CO₂ (which are primary controllers of temperature and, therefore, water vapor content). Also, human effect on vegetation and soil currently produces a much bigger impact on cloud formation and rainfall. If atmospheric CO₂ stops increasing, combustion of hydrogen should thus not impact climate significantly and could be considered green. However, with continued increase in atmospheric CO₂, increase in water vapor with hydrogen combustion will have an impact. And this impact won't be insignificant unless human population decreases its energy usage. Although most do, not all clouds form below stratosphere. One exception are polar stratospheric clouds that form at the poles in winter, and if additional atmospheric water vapor is distributed to the poles, these clouds will be contributing to the melting of ice in Antarctica (producing more warming and vapor) unless additional cloud formation is coupled with ozone depletion which may balance the heating with a cooling effect. In any case, the claims of zero-emission hydrogen combustion are false and misleading. Emissions during production Most hydrogen produced today (over 95%, as of 2020) is produced from fossil fuels - mainly by steam reforming of natural gas, but also other light hydrocarbons, partial oxidation of heavier hydrocarbons, and coal gasification. These processes are emitting a lot of greenhouse gases (mostly CO₂). The hydrogen produced this way is called gray hydrogen, it's cheapest, but it simply doesn't make sense to associate it with zero-emissions or anything clean. The power produced from natural gas would be more clean than power produced from gray hydrogen. The story is similar with, so called, blue hydrogen. It is produced the same as gray hydrogen but CO₂ is captured and stored underground with a hope it won't leak into atmosphere for at least 100 years. It is still better to burn natural gas or even coal than blue hydrogen. Then there is the turquoise hydrogen - hydrogen produced by methane pyrolysis. This process doesn't release CO₂ as a byproduct, rather solid carbon and can be produced at less cost than blue hydrogen. However, even if there are no direct emissions, producing hydrogen from methane is generally not environmentally friendly and there are problems with leakage. But probably the biggest problem here is the fact that the companies extracting natural gas (containing methane) are companies extracting oil - at what price will they be able (or willing) to extract methane without also extracting oil (considering the fact that natural gas is generally formed deeper than oil)? And will the extracted methane be used solely for production of hydrogen and not for other purposes - e.g., heating, where combustion is releasing CO₂? The turquoise hydrogen, therefore, probably also doesn't make sense unless the methane is renewable (e.g., methane produced from biomass, not extracted from the deep). But the problem is - there's simply not enough renewable methane available even if it could be produced cheaply. In US, for example, available renewable methane could replace only 10% of fossil gas in use. And if you do have renewable methane, it is much better to use it to replace fossil gas in use rather than use it to produce hydrogen. This leaves us with green hydrogen - produced by electrolysis of water using renewable energy sources. Here the question is - why? Why complicate (and lose energy) converting electricity to hydrogen (which is in fuel cells converted back to electricity) when one can use electricity directly or store it into a battery with less energy loss and no issues with compression and transport? In case of storage, the only advantage is the greater energy density of hydrogen fuel cells, compared to lithium-ion batteries. This can result in bigger range and lighter vehicles but, overall, likely not worth it in case of automobiles. The other advantage may be in production - it may be more environmentally friendly to produce green hydrogen and hydrogen fuel cells than batteries. But if we use electricity to produce hydrogen for vehicles (using green hydrogen fuel cells to power your house instead of using green electricity simply doesn't make sense) that will cause additional strain on the electrical grid which will then need additional capacity. Production of green hydrogen, thus, probably only makes sense when there is surplus electricity that would be unused otherwise. Conclusion I don't see hydrogen as a significant energy source in future (unless used in nuclear fusion, but I'm not convinced humanity will advance that far). It could be forced, politically, as dominant energy source but who will be able to afford it? Perhaps one way to deal with climate change is to reduce the number of polluters by rising prices of energy. Certainly, hydrogen based energy sources, regardless of the way hydrogen is produced, are more expensive than others. Hydrogen is unlikely to replace fossil fuels and is an unlikely solution to climate change, but green solutions are becoming increasingly expensive for the average Joe who is increasingly being more concerned with life today than with life tomorrow, even though it is precisely that kind of reasoning that created the problem. We can talk about hydrogen today and about whatnot tomorrow but there never were real solutions other than the transformation of polarized human mind. Will the average Joe be willing to significantly sacrifice his lifestyle for long-term survival or will his kind fall-back to [short-term] cheaper fossil fuels? What about the average Jane? The answer is, of course, clear already, and it will be becoming clearer and clearer with decreasing maneuvering space for delusional subventions.