In China, the world’s first commercial power station utilizing supercritical carbon dioxide ($\text{sCO}_2$) instead of steam has commenced operation. The facility, named “Chaotan One,” situated at a steel plant in the city of Liupanshui, Guizhou Province, is connected to the grid and is functioning successfully. This occurrence marks a breakthrough, interrupting the century-old custom of applying steam turbines for electric power generation. Since the invention of the steam engine, which initiated the industrial revolution, water vapor has remained the main working fluid for converting heat into mechanical work. However, a significant portion of the energy in such systems is spent on the phase transition of water into vapor—a process demanding high energy input. Scientists, striving to boost the overall efficiency of energy installations, have discovered an alternative in supercritical carbon dioxide. The supercritical state of $\text{CO}_2$ is achieved at a temperature of approximately $31^\circ \text{C}$ and a pressure of $7.37 \text{MPa}$. In this state, the substance combines the properties of a liquid and a gas: it fills a volume like a gas but possesses high density, similar to a liquid. This makes it an extremely effective working fluid for turbines, providing less resistance than steam and simultaneously greater motive force. Furthermore, converting $\text{CO}_2$ to its supercritical state requires less energy than transforming water into steam. “Chaotan One” comprises two units, each with a capacity of 15 megawatts, and is designed to recover waste heat from steel production. According to Chinese media, the new technology allows for a 50% increase in net electricity output compared to traditional steam installations, and the overall generation efficiency rises above 85%. The design of such a power plant is simpler, contains fewer elements, and is distinguished by ease of operation and upkeep. This project demonstrates not only the practical feasibility of the $\text{sCO}_2$ technology but also opens the way for the effective harnessing of medium and small heat sources for energy generation. Although similar developments are actively being pursued in other nations, including the USA, it is China that has been the first to implement it in commercial service. The success of “Chaotan One” may herald the arrival of a new era in energy, where carbon dioxide becomes a key component, supplanting water vapor.
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