Sécurité énergétique

Résumé

vignette| Un Boeing F/A-18 Super Hornet de l'US Navy affichant un logo "Energy Security". La sécurité énergétique est l'association entre la sécurité nationale et la disponibilité des ressources naturelles pour la consommation d'énergie. L'accès à une énergie (relativement) bon marché est devenu essentiel au fonctionnement des économies modernes. Cependant, la répartition inégale des approvisionnements énergétiques entre les pays conduit à des vulnérabilités importantes. Les relations énergétiques entre les nations ont contribué à la mondialisation, ce qui peut permettre à la fois la sécurité énergétique et la vulnérabilité énergétique. Les énergies renouvelables et les mesures d'efficacité énergétique et de transition énergétique peuvent prendre place sur de vastes zones géographiques, contrairement à d'autres sources d'énergie qui sont elles concentrées dans un nombre limité de pays. Le déploiement rapide des énergies renouvelables et de l'efficacité énergétique, couplé à la diver

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In the last decade, the exponential development of shale gas activities in United States resulted in a real revolution both in terms of gas prices and energy security. However, next to these positive effects, many risks and impacts for the environment and for human health related to shale gas activities have been identified. Risks of water and soil contamination or air pollution issues related to shale gas activities have been revealed in different recent scientific studies. During the last years, and because of the growing concern of local populations, shale gas became very debated in the media. In the scientific community as well, shale gas is a debated issue but in terms of greenhouse gases (GHG) emissions. This study is a scientific assessment of the environmental impacts related to shale gas extraction trying to synthesize information available from different scientific studies and providing potential mitigation measures. As Poland currently plays the most active role in European shale gas exploration, it has been chosen has the reference location in order to evaluate the different impacts. The results are that potential impacts on both human health and the environment can potentially be important but that an important lack of reliable information exists in order to fully assess most of the potential risks related to shale gas activities. Due to the high sensitivity of this issue among scientists, shale gas GHG emissions have been calculated in this study using a Monte Carlo simulation in order to define potential results based on variable parameters instead of using fixed values. The results show that shale gas GHG emissions could be 28% larger than coal over a 20 year timeframe and identical to coal over a 100 year timeframe. Mitigation measures can however reduce shale gas emission and most of the other impacts. The largest problem in order to currently asses and adequately reduce the risks related to shale gas activities is the current paucity of reliable information. An important uncertainty indeed exists in the evaluation of most of the risks. Many more scientific studies are therefore urgently needed in order to fully assess the potential impacts of shale gas activities and in order to ensure that the development of such activities will be done in Poland in the best possible conditions. In the meantime, the biggest risk would be to not accept our current ignorance and a precautionary approach should therefore be adopted.

2012

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Characterisation of a 200 kW/400 kWh Vanadium Redox Flow Battery

Véronique Amstutz, Hubert Girault

The incessant growth in energy demand has resulted in the deployment of renewable energy generators to reduce the impact of fossil fuel dependence. However, these generators often suffer from intermittency and require energy storage when there is over-generation and the subsequent release of this stored energy at high demand. One such energy storage technology that could provide a solution to improving energy management, as well as offering spinning reserve and grid stability, is the redox flow battery (RFB). One such system is the 200 kW/400 kWh vanadium RFB installed in the energy station at Martigny, Switzerland. This RFB utilises the excess energy from renewable generation to support the energy security of the local community, charge electric vehicle batteries, or to provide the power required to an alkaline electrolyser to produce hydrogen as a fuel for use in fuel cell vehicles. In this article, this vanadium RFB is fully characterised in terms of the system and electrochemical energy efficiency, with the focus being placed on areas of internal energy consumption from the regulatory systems and energy losses from self-discharge/side reactions.

2018

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Thermo-economic evaluation of coal power plants with CO2 capture

Jeremy Urech

Actually the world is facing the dual challenge of energy supply security and mitigating climate change due to greenhouse gas emissions. In this context different alternatives to reduce the atmospheric CO2 emissions are increasing the efficiency, switching to renewable resource and reduce emissions from fossil resources by CO2 capture and storage (CCS) . In power plants three different CCS concepts have emerged: post-combustion applying an end of pipe technology to remove CO2, oxy-fuel combustion (i.e. pure O2 oxidation) and pre-combustion (i.e. H2 routes). Coal power plants are supplying a large amount of the world's electricity and contributing to the CO2 emissions increase. The goal of the project is to study the performance of coal power with CO2 capture and to assess the energy penalty and cost of capturing CO2.

2011

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