Thursday, January 9, 2020

Science & Technology: Geothermal District Heating and CO₂ Capture and Storage Project

What if storing CO₂ would also allow us to heat our homes? (The Conversation)

BRGM (Bureau de Recherches Géologiques et Minières) has been involved in several research projects on CO₂ capture and storage (CCS) over the past 25 years. Since 2013 however, BRGM and its partners have been working on a new CCS option that is simpler to implement, less expensive and suited to downscaling so it can be applied locally to reduce CO₂ emissions from “small” industrial facilities.

The CO₂-Dissolved solution, developed by BRGM, proposes a new approach to CCS that is perfectly adapted to these small industrial emitters. One main difference is that the CO₂ is stored entirely dissolved in the salt water of a deep aquifer, as opposed to the conventional approach where CO₂ is compressed into a dense state.

To do this, water is pumped from the deep reservoir via a production well before being reinjected back underground via a second injection well, after dissolution of the CO₂ captured at the industrial plant. Together these two wells constitute what is called a “doublet”, identical to the doublets used in deep geothermal exploitation. This similarity of infrastructure makes it possible to extract simultaneously the heat contained in the water pumped from the reservoir.

Not only would the storage of these emissions substantially improve the carbon footprint of these industries, but the added advantage of using geothermal energy as a means of heating and thus replacing fossil-fuel energies would further reduce the environmental bill.

Ongoing work is aimed at preparing the first CO₂ injection tests in an existing geothermal doublet. This will validate the essence of the CO₂-Dissolved concept, by testing in particular the injection device and the methods of continuous monitoring of the CO₂ dissolution in the water of the injection well. The next step will be to implement, on an industrial site, a first demonstrator of the full technology.