Topic Description

Carbon capture and storage (CCS), enhanced geothermal systems (EGS) and unconventional gas development impact on the subsurface. Subsequently, advanced and cost effective monitoring of the containment of underground CO2 and natural gas is vital for the sustainable management of the subsurface and its resources.

In CCS, the safe and permanent geological storage of CO2 requires a continuous and sophisticated monitoring of the storage complex. For enhanced geothermal systems, the use of supercritical CO2 has been proposed as a circulating heat transmission fluid. The CO2 would bring the advantage of a low viscosity and hence low flow resistance as compared to water, and could achieve permanent storage of CO₂ as a supplementary benefit. In both CCS and EGS, robust monitoring is a key prerequisite for the safe and sustainable storage or circulation of significant volumes of CO2 in the subsurface.

Technological progress, in particular the combination of horizontal drilling with multiple stages of hydraulic fracturing, has enabled the development of unconventional hydrocarbon resources. This has resulted in new opportunities, but also bears environmental and public health risks, which need to be better understood, monitored, managed and communicated appropriately. These risks relate mainly to water pollution (in particular stemming from insufficient underground characterisation, inappropriate well casing, the use of chemicals in the fracking process, and waste management), but also air emissions as well as local impacts linked in particular to transport, land and water use.

Research is needed to better understand and quantify possible (natural and engineered) leakage pathways for natural gas, the rates of leakage into aquifers and escape at surface, the impacts that leakage can have on fresh groundwater resources, soil and biodiversity, and the time frame in which emissions will return to baseline values. In addition, the effective detection and quantification of leakage requires a scientifically robust method for determining natural background concentrations of CO2 and natural gas in the soil and at the surface.

Uniform, unbiased and independent data are needed to improve environmental stewardship in all three aforementioned geo-energy applications.

The exact scope of this topic will be further specified in the course of 2016, taking account of, inter alia, the review of the effectiveness of the Commission Recommendation of 22 January 2014 on minimum principles for the exploration and production of hydrocarbons (2014/70/EU) (such as shale gas) using high-volume hydraulic fracturing, as well as preliminary findings from four projects on environmental impacts of unconventional gas funded under Horizon 2020 2014-2015 Work Programme.

To be further specified in the course of 2016. This topic may provide European and North American researchers with a platform to enhance and deepen transatlantic dialogue on environmental and public health issues related to these three applications.