The water can be saltwater, and if you set up the system as a loop, you can reuse the same water as it comes back up without the CO2. The limiting factor is the

The water can be saltwater, and if you set up the system as a loop, you can reuse the same water as it comes back up without the CO2. The limiting factor is the drilling -- you need lots of deep holes in the ground, and making those is costly. It's not a surprise that this was pioneered by a geothermal company, as drilling is their main expertise. The big remaining unknown is how long can they reuse the same hole before all basalt in there is covered in calcium carbonate. Since drilling is the main cost, and this determines how often you have to drill, it can either make this project feasible or totally unusable.