Potential Environmental Impacts of CO2 Leakage from the Study of Natural Analogue Sites in Europe

AbstractSites of natural CO2 leakage provide opportunities to study the potential environmental impacts of such leakage on near-surface ecosystems. As part of the FP7 RISCS (Research into Impacts and Safety in CO2 Storage) project a geochemical, botanical and microbiological study have been conducted on a natural CO2 vent in Florina, Greece and the findings are compared with the results drawn from Latera, Italy and Laacher See, Germany. Plant and microbial communities appear to have adapted to long-term CO2 exposure. Therefore the findings may not be representative of the effects of potential leakage from man made storage sites

Comparison of the impacts of elevated CO₂ soil gas concentrations on selected European terrestrial environments

Selected European studies have illustrated the impacts of elevated CO₂ concentrations in shallow soils on pasture. For the first time, general unified conclusions can be made, providing CO₂ thresholds where effects on plants and soil microbiology are observed and making recommendations on how this information can be used when planning projects for CO₂ storage. The sites include those where CO₂ is being naturally released to the atmosphere from deep geological formations; and a non-adapted site, with no previous history of CO₂ seepage, where CO₂ has been injected into the unsaturated soil horizon. Whilst soil gas concentrations will be influenced by flux rates and other factors, the results suggest that a concentration of between 10% and 15% CO₂ soil gas at 20 cm depth, which is within the root zone, is an important threshold level for observing changes in plant coverage. Site-specific plant ‘indicators’ are also observed for CO₂ concentrations at ≥35%. Microbiological changes are seen where CO₂ soil gas concentrations are between 15% and 40%. As part of site characterisation, an evaluation of the risks of leakage and their potential environmental impacts should be undertaken

Cost of pipeline-based CO2 transport and geological storage in saline aquifers in Greece

AbstractThis work aims to provide an insight of the cost estimation for large scale CCS application in the Greek thermal power plants given the high dependency on fossil fuels for the bulk of the national electricity generation and the aim to fulfil Greece’s share of the overall European energy policy targets. Greece generates almost 92% of its electrical power requirements from fossil fuels, with lignite accounting for about 63% of the total while the share of liquid fuels and natural gas is 14% and 22% respectively (2007). Total CO2 emissions increased from 83.15 Mt in 1990 to 113.56 Mt in 2007. This increase of 36.57% from 1990 to 2007 is mainly attributed to the increased electricity production (average annual rate of 3.6% for the period). Taking into consideration the forecasts for increase in the electricity demand over the coming years and the old and low-efficiency units that should be either renovated or replaced by new units, the capture and geological storage of CO2 is considered as a critical climate change mitigation option at national level.In particular, the cost calculations are focused on CO2 transport from a new capture-ready 650 MWe coal fired power plant using supercritical steam cycle, to be erected in the Region of Western Macedonia, to potential geological formations via pipeline and the subsequent storage in deep saline aquifers. The cost estimations are based on a pipeline transport infrastructure linking one large CO2 source with individual storage sites. The results from the geological characterisation and the storage capacity of the identified Prinos, West Thessaloniki, and Messohellenic Trough - Pentalophos saline formations in the Tertiary sedimentary rocks of Greece will be presented.To conclude, the geological properties of the sedimentary basins in Greece appear to to have the potential to sequester billions of tons of CO2 for CCS implementation. The identified geological reservoirs occur within approximately 100–200 km of the majority of stationary CO2 emissions in Greece, which is favourable in terms of infrastructure costs for the development of a CO2 pipeline transport network. However a range of R&D activities is required in order to assess the effective CO2 storage potential of saline aquifers in Greece like a more detailed site–specific geological analysis, stratigraphic mapping and correlation, petrophysical property characterization, generation of quantitative and dynamic 3-D geological models, geochemical simulations etc