Geothermal Emission Control

GECO will advance in the provision of cleaner and cost-effective non-carbon and sulphur emitting geothermal energy across Europe and the World. The core of this project is the application of an innovative technology, recently developed and proved successfully at pilot scale in Iceland, which can limit the production of emissions from geothermal plants by condensing and re-injecting gases or turning the emissions into commercial products.

To both increase public acceptance and to generalise this approach, it will be applied by GECO in four distinct geothermal systems in four different European countries: 1) a high temperature basaltic reservoir in Iceland; 2) a high temperature gneiss reservoir in Italy; 3) a high temperature volcano-clastic reservoir in Turkey; and 4) a low temperature sedimentary reservoir in Germany. Gas capture and purification methods will be advanced by lowering consumption of resources, (in terms of electricity, water and chemicals) to deliver cheaper usable CO2 streams to third parties. Our approach to waste gas storage is to capture and inject the soluble gases in the exhaust stream as dissolved aqueous phase. This acidic gas-charged fluid provokes the dissolution of subsurface rocks, which increases the reservoir permeability, and promotes the fixation of the dissolved gases as stable mineral phases. This approach leads to the long-term environmentally friendly storage of waste gases, while it lowers considerably the cost of cleaning geothermal gas compared to standard industry solutions.

A detailed and consistent monitoring program, geochemical analysis, and comprehensive modelling will allow characterising the reactivity and consequences of fluid flow in our geologically diverse field sites letting us create new and more accurate modelling tools to predict the reactions that occur in the subsurface in response to induced fluid flow. Finally, gas capture for reuse will be based on a second stage cleaning of the gas stream, through amine separation and burn and scrub processes, producing a CO2 stream with H2S levels below 1 ppm, which is the prerequisite for most utilisation pathways such as the ones that will be applied within the project.

The tasks carried out during this first period have focused on data acquisition, modelling and laboratory experiments that form a basis for the forthcoming pilot demonstrations during the project’s later stages. At the onset of the project, a detailed project management plan was constructed with a Gantt chart and a work breakdown structure along with a schedule per task, responsible partner, related subtasks, deliverables and dependencies on other tasks. An internal communication plan and visual identity was put in place including communication tools and a website. Training and outreach activities have been carried out and are detailed in the periodic dissemination report. Also, an annual report on the communication process and performance for year one was submitted.

The modelling work under WP2 has been largely completed. We have characterised each demonstration site based on local geology, lithostratigraphy, mineral alteration, tectonics, structural features, and hydrological conditions. This was followed by detailed reservoir modelling and sensitivity study of the demo-sites that included numerical simulations under steady state conditions and geophysical data constraints of the characterised reservoirs of each demonstration site. Finally, properties of the steady state flow module were determined for different gas mixtures to be used to form the basis for optimal CO2 and water injection.

In WP3, the characteristics of both the amine-based CO2 purification system characteristics and the burn and scrub purification system have been analysed in preparation for the demonstration system design. Basic design and integration of these systems was also completed. In addition, details on the specification and validation of purified gas were provided.

In WP4 we have prepared several reports in preparation for injection in the later stages of the project. First, a synthesis report on thermodynamic models of CO2/H2S/brine systems describing the reference database that will be used for modelling the Castelnuovo injection well. Second, a report on precipitation/dissolution effects of CO2/brine on different rock types and materials at different temperature and pressure conditions. Calibrated modelling predicts intermediate and long-term reservoir rock-fluid interactions and the efficiency of CO2 storage. Third, a synthesis report on experimental measurements of CO2 absorption in pure water and the dissolution kinetics, under variable temperature and pressure conditions.

All demonstrations, WP5-WP8 have entered the design and engineering phases (apart from WP6). The procurement and construction of the demonstrations will start during the next period.

In WP9, preliminary activities concerning the IPR management, environmental and economic evaluation have been initiated.