Greenfire Energy, a new geothermal/CCS company, has been chosen by the Department of Energy (DOE) to receive $2 million as finance for a geothermal trial project that utilizes injected carbon dioxide as functioning fluid in the well instead of water.
The award is a part of the $20 million allocated by Energy Efficiency and Renewable Energy program of DOE for financing novel geothermal technologies.
Geothermal Field
The pilot project of Greenfire Energy, if successful will allow production of base-load electric power by utilizing a lower level of geothermal heat, which is widely available all over USA. It will also assist in saving a good amount of water currently utilized for power generation and assist in geologically secluding of carbon dioxide. The company is planning to utilize the natural stocks of carbon dioxide located at an used up gas field for conducting the tests. According to its associates, such as an oil industry engineer, ecological expert, a chemist and a specialist in geology, the technology proposed for the project deems to be good to produce power with lower level investment than normal geothermal projects.
According to Mark Muir, President of GreenFire, Carbon dioxide expands better than water with the increase in temperature to drive the systems. He said if the company chooses to deploy a closed binary system for the pilot project, the rocks below the ground will be used to heat carbon dioxide into a supercritical condition to send it to the surface to heat the second fluid incorporated, which in turn will rotate the turbines to produce power. The supercritical carbon dioxide will be wheeled through the system again and again to produce power. He estimates that around 5 to 60% of carbon dioxide will remain entrapped underground.
The use of carbon dioxide as a geothermal drilling fluid in place of water provides a number of advantages. The lower level of viscosity of carbon dioxide than that of water makes it convenient to inject over rock formations. The storage and transportation of carbon dioxide is comparatively easier than that of water and does not require higher level of heat or pressure. The technology does not need cooling towers or pumps and can be cooled at superficial depths thus saving on drilling costs. The demo project from its beginning to power generation phase is anticipated to cost Greenfire Energy around $32 million.