Comment by nine_k
7 hours ago
> perfectly reversible, but that uses a lot of energy
Looks like a perfect match to a solar plant, which provides basically free energy periodically. All you need is a large enough cistern to hold the liquid during night time.
Yes, it's a great match to solar plants.
But you don't need to store the capture medium. You use a bit more energy to make they work faster while the Sun is shining, and stop everything when it's gone.
The largest bottleneck is what you do to get rid of the CO2.
We use the CO2 to synthesize methanol with the H2 we electrolyze using surplus solar energy. The methanol we burn in winter for heat. Yes, that releases the CO2 again. The goal here is not to save the planet. It is to bring solar energy to winter. My house produces many times the electricity that it needs per year, but most of it is wasted in summer. Efficient conversion is not a factor. If I can get 20% of the energy input back as heat in winter, it is worth it: that is oil or wood I don't have to burn for heat.
I mean, you have to recycle the CO2-carrying liquid. You have to store some of it that has CO2 captured but not yet recycled because the Sun is down.