Where the emission capture stations being setup? How will you guarantee the electricity used to capture the CO2 is clean?

They are working on the tech, not rolling it out.

To answer your questions:

1) Capture stations will be setup wherever the people who license the tech or purchase equipment want it to be setup.

2) The easiest way to guarantee the electricity used is Green is to only plug the equipment into Green electricity sources. Which makes economic sense too if you can afford the initial outlay. Plus it means you can sell your methane as a Green fuel without being put on trial for fraud, a bonus if that is a better market.

For hydrogen in Europe to be considered green - if I’m not mistaken - you need not just carbon neutral sources, but also you need them built specifically for the purpose of capturing hydrogen. It can be tracked.

They have a website https://www.gengalactic.com/

The physics of this seem near impossible. Obviously you can make methane from CO2 and water, but making it more cheaply than pumping it out of the ground? Nat gas futures are $1.61 per cubic foot. Where are they going to get the enormous amount of energy to power this process?

Usually the proposal is massive solar arrays, and maybe only producing during daylight hours to avoid battery costs, and spreading the upfront build cost over the solar array's lifespan. I think a lot of this falls down though when doing the finance, as people realize they can make more money selling the electricity to the grid rather than using it for their energy intensive project.

Above certain threshold of solar in the grid it’s not necessarily so. Also there are locations that are good for solar and available but have terrible grid connecting capabilities.

depends on where you are. California reduced the incentives for home solar to the point where it's more lucrative to mine Bitcoin with excess solar energy rather than sell it back to the grid.

A project like this is going to rely on using energy when it's so over-supplied to the grid that prices drop to near zero. Which does cause some financial challenges, as your expensive machinery isn't running all the time, but it's different to just the energy being worth something.

The physics are very possible. The challenges of scaling and making it economically viable, now thats another matter.

With the current trends in the economics of energy, the thermodynamics is not really a limit: the electricity you need is generally available cheaply (or even at negative prices) at certain times of day. The biggest issue is getting anywhere close to that thermodynamic limit, and the cost of building the equipment in the first place. Capturing CO2 from air takes a lot of surface area and a lot of energy before you even do the 'turn into methane' step, and because the energy is only available at certain times, you can't run your plant continuously so the initial costs amortise badly. Those are the areas that need solving to make this concept work.