Uncharted Territories -- Part 3

[Philip Costa]

From Air to Gas

First, you use some energy to take in air and isolate its CO₂ in a concentrator.

The energy can come from solar panels.

Then you need to take some water and split its hydrogen and oxygen, forming H₂ and O₂. You throw away the oxygen, like plants do.

This machine is called an electrolyzer. So you need two machines so far: a CO₂ concentrator and an H₂O electrolyzer to get H₂.

Finally, you combine the CO₂ and H₂ into a reactor to form CH₄⁵.

This part actually generates heat, because the H₂ molecule has a lot of latent energy. So no need to plug in more energy here. Source: Terraform Industries

This machine is now being built, and will be on sale starting next year.

The only thing missing here are the solar panels. Source: Terraform Industries’ blog post introducing this machine.

Remember how we talked about the Haber-Bosch process to create fertilizer? It’s been around for over a century and is probably the biggest driver of human population. This process to generate methane is nearly the same, but instead of extracting N₂ from the air to produce NH₃, we get CO₂ from the air to get CH₄. Aside from these details, it’s very similar.

1. You put in air, water and energy, that’s all

2. Air is free

3. Water is nearly free⁶ 

4. The only big cost here is energy 

This process must produce a cubic meter of CH₄ cheaper than the current market price, which historically has been about $0.18⁷—and reached about $2 at the beginning of the Ukrainian war.

How much energy does this process need?

If you install solar panels that have a capacity of one megawatt (1 MW), they should produce about 128 m³ of CH₄ in a day. Since we said the historic price of CH₄ is about $0.18, that means a 1 MW solar panel can produce $23 per day of operation, or about $10,000 per year. With 30 years of operation⁸, that’s $300k generated. 

If you look back at the graph above, you’ll see that the cost per W of solar panels was $0.27 in 2021. So 1 MW is $270k. In other words, these are already at the same order of magnitude!⁹

The costs of gas from the ground and from solar energy are in the same order of magnitude.

Obviously, the cost is not just the panels—it’s also the land, transmission lines, the people, and the machines (concentrator, electrolyzer, and reactor) to produce the methane. But the point here is that the single biggest cost—energy (via solar panels)—could already allow the process to break even¹⁰. Now drive that cost down by 12% every year, and it’s a matter of time for gas from the air to become cheaper than from the ground.