American Supercritical has emerged from stealth with $8 million in funding to retrofit the simple-cycle gas turbines used by many US data centres. Its supercritical carbon dioxide technology would capture waste heat and convert it into extra electricity, improving efficiency without increasing emissions or water use, although the underlying gas turbines would continue releasing carbon pollution. The approach matters as data-centre electricity demand grows and inefficient generation threatens to worsen climate impacts.

Simple-cycle turbines convert roughly 35 per cent of their fuel’s energy into electricity, compared with 60–65 per cent for combined-cycle plants, because they do not use exhaust heat to produce steam. The company plans to begin with 10-megawatt units, claiming they could raise turbine efficiency by up to 50 per cent through a closed-loop carbon dioxide system that avoids additional fuel combustion and largely eliminates water use. However, the technology would not make gas-fired power emissions-free, and a Texas data-centre plant cited in the article is permitted to emit more than 33 million tonnes of greenhouse gases annually.