MV#9 — The Hunt for H2 — Rūta Karolytė

For many years scientific consensus has averred that hydrogen does not occur naturally in significant quantities without being bound to other atoms (such as in H20, water, or CH4, methane). To obtain the gas — whether as a fuel or for use in fertilizers — we need to strip it from those molecules — typically by electrolysis and steam reformation. But our understanding may be ripe for change.

Website of National Renewable Energy Laboratory from February 2023, following the publication of a New York Times article on natural H2, the text was changed to “Because hydrogen typically does not exist freely in nature” (emphasis mine)

Rūta Karolytė is at the vanguard of prospectors looking for large, naturally occurring reservoirs of hydrogen. She’s a researcher from Oxford specializing in the geochemistry of the Earth and she enlightens us to the mechanisms that are likely to be producing hydrogen in the crust: radiolysis and serpentinization. 

In reviewing the evidence for naturally occurring hydrogen we pass through exotic terrain: a Soviet-era theory of hydrocarbon production, fairy rings, hydrothermal vents and chemosynthetic life. These organisms, remarkably, do not depend on the sun, plants, or any other life forms for their energy. Instead, they draw directly from the power stored in inorganic compounds. Their existence is testimony to the natural occurrence of hydrogen.

This does not guarantee that hydrogen is present in large quantities, but modeling of the processes that produce it — particularly serpentinization — suggests it is. Serpentinization is a kind of rusting whereby rocks are oxidized and hydrogen is freed from water molecules, wherever water and the right kinds of rocks are present and the pressure and temperature are right, hydrogen will be produced. What is more this process could be sped up by the introduction of more water underground.

If Rūta and her fellow prospectors are correct, the tapping of natural hydrogen could have transformative consequences for the “Hydrogen economy” — such as cutting out the substantial fossil fuel emissions associated with deriving fertilizers from methane or creating a cheap basis for building synthetic fuels.

In the first half of the show, we also delve into carbon sequestration — another cool climate topic. But I’ve got so excited writing up the first half, that I’ll leave it here. 


MV#1 — Mining the Air — Casey Handmer

Hydrocarbons are not bad. Over the last three hundred years they have propelled global growth and technology. Steel, trains, planes, plastics, and processors owe a historical debt to the energy that we have readily extracted from coal, oil and gas. 

The way we get hydrocarbons is bad. In taking them from the ground and burning them we transport carbon from the crust to the air. The deleterious consequences of this on our climate are well known. Furthermore, the inhomogeneity in their distribution has led to global iniquities, indeed reserves of such natural resources continue to prop up unsavory regimes, even eliciting deference from other powers that profess to uphold more democratic principles.

Casey Handmer, founder and CEO of Terraform Industries (TI) joined me on the inaugural episode of the Multiverses podcast. He has a plan to create a cleaner, fairer hydrocarbon economy:

  • Extract hydrocarbons from the air. Keeping the atmospheric balance intact — even improving it. 
  • Make this work almost 
  • everywhere. By relying on more equitably distributed resources: sunshine and air 
  • Do this more cheaply than drilling

Casey has Ph.D. in theoretical astrophysics and has worked at NASA’s JPL and at Hyperloop One. 

The technology behind the plan is old: scrub carbon from the air (like plants!), use water to create Hydrogen (electrolysis — discovered ~1800), combine the hydrogen and carbon using the Sabatier process (discovered ~1900) to produce methane. Methane, or natural gas, is the gateway hydrocarbon — CH4 — easy to transport and can be used as the basis for more complex synthetic fuels.

The economics that makes this work is new. It requires copious, low-cost energy from solar PV for this process to undercut crust-mined methane. That energy is used to turn the fans that churn through the air, electrolyse the water and run the Sabatier process. Using projections of solar energy costs, Casey estimates that in the mid-2030s it will be cheaper in most inhabited places to generate hydrocarbons this way than by drilling.

Because TI is confident that solar power will continue to fall, its efforts are focused on building something that can quickly get mass adoption — that means building cheap machines rather than ones using expensive components that could operate at higher efficiency. When PV is super cheap, we can be wasteful of it if it means a faster transition to net zero. We don’t need highly efficient processes to create fuels, we just need a lot of solar. 

If the TI thesis plays out, it will enable a phase change in solar adoption. In many cases it does not currently make sense to connect more solar to grids — it only adds to generation at hours that are already well covered. More storage solutions and HVDC to move energy between time zones will change that. Even then, it’s hard to connect new solar farms — it can require years of permits to get the grid interconnections laid. If it becomes cheaper to produce methane from the air then the grid constraints are bypassed, a solar farm can be constructed anywhere with access for trucks and the methane produced can be stored in the mundane ways (tanks).

I hope it happens.

Questions I’d ask if I had this conversation again

Is there a floor to solar costs?  A couple of reasons to think there might be:

  • It uses up some natural resources and the cost of these has floor. Does plywood installation display a learning rate? Perhaps slightly, but it’s masked by resource costs.
  • Solar needs land area, another constrained resource. 

What about air-to-food? Startups like solar foods are following a similar model in turning energy from the sun into hydrocarbons. Could there be any advantages to colocating facilities for food an methane production? Will the prices of food and fuel equalize in terms of $ per joule? The cheapest food is currently about 18MJ Joule per dollar (see whereas gasoline is more like 60MJ per dollar — so it’s about three times as cheap. Will food become relatively cheap compared to gas? Even with gas coming down in price. More good news?!

Update — Casey got back to me by email with some comments on these:

  • Cost floor: Might get as low as $30k/MW. Land cost becomes important at that level without severe regulatory assistance! [JR: for ref, the turnkey installed cost is $900k per MW at the low end currently — so the floor is a long way down]
  • Air-to-food: Food is actually about 100x more expensive than gasoline per usable unit of mechanical energy. Probably better to collocate synthetic food factories (if any) with centers of demand, as food is less transportable than natural gas through existing natural gas pipelines!

References: — Rupert Way et al on why renewable costs will continue to come down (the “learning rate”) Technology Quarterly from The Economist (paywall) on electricity grids