REVISTA DYNA ENERGÍA

This technology has already been presented in DYNA Magazine when it was studied at laboratory level by Sandia National Laboratories (USA) and a group of companies (https://www.revistadyna.com/busqueda/como-socios-energeticos-sandia-national-laboratories-lidera-a-industria-en-busqueda-de-una-electrici). The article presented the advantages of using supercritical CO2 over the usual water-steam system in current turbines and the change from the usual Rankine cycle to the Brayton cycle of the new turbines: the size of the turbines is reduced 10 times for the same power and the energy yield, which is just over 35% of the water-steam system, is increased by 10%. This, which may seem a small gain, represents a significant cost and emissions advantage.
Supercritical is the temperature-pressure state of a fluid at which it ceases to act as a gas or liquid and instead begins to act as a gas with the density of a liquid. Beyond this point, relatively small changes in temperature can cause significant changes in density. CO2 becomes supercritical when the temperature and pressure exceed 31°C and 74 bar respectively. Water can also become supercritical, but this requires much more energy, as it requires a temperature and pressure above 373°C and 220 bar. For this reason and the characteristics of being cheap and non-flammable, CO2 is the ideal material for the process.
The STEP Demo project, in which General Electric is participating, has involved an investment of 155 million dollars, and is part of the projects to improve technologies that, while using a fossil fuel such as natural gas, can generate electricity at a lower cost and with fewer emissions.