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Though carbon capture and storage (CCS) gains its momentum in China in context of the energy-mix that features heavy reliance on coal, it is currently obscure and full of uncertainty, of which a primary concern goes to the cost viability of CCS. However, previous technical-economic studies mainly take a static perspective to look into the cost of carbon capture systems, without fair consideration of the potential future cost slide brought by continuous expansion of CCS technologies and technical improvement. In recognition of this, a dynamic cost analysis is undertaken in our work by applying learning curve to exploring CCS prospect in China, together with a detailed review of domestic CCS progress. An oxyfuel power plant retrofitted from a typical traditional 2×600 MW power plant in China is chosen as a case study. The result suggests that the unit capital cost for the oxyfuel combustion plant will fall from 4926.30 RMB¥/kW to around 2977.02–3981.20 RMB¥/kW and the cost of electricity is supposed to drop drastically from the initial level 459.70 RMB¥/MWh to around 342.29–399.37 RMB¥/MWh when the aggregated capacity reaches 100 GW. The sharp decline forecasts that in the long term CCS technology could be a cost-effective option to be deployed together with other clean energy options. In addition, compared with IGCC and post-combustion systems with carbon capture, the oxyfuel combustion technology is illustrated quite competent in the long-term deployment. [ABSTRACT FROM AUTHOR]

The household-scale biogas system gains its popularity in rural China, and is now playing a prominent role in relieving energy shortages and reducing environmental pollution. A comprehensive review is performed for related environmental and ecological assessment studies. For an overall assessment of the biogas system, especially for its renewability and sustainability, an updated exergy methodology in terms of cosmic exergy is introduced in this paper, and is concretely illustrated by a case study to an integrated biogas engineering in Hubei, China. Associated with the fundamental universal scale of the cosmic-solar-terrestrial ecosystem, this new approach aggregates natural resources, economic inputs and environmental contamination on a common basis. Furthermore, a series of cosmic exergy based indicators are established to quantify the renewability and sustainability of the system. The integrated biogas engineering is proved to be with remarkable positive net ecological benefits, around twice that of the corresponding conventional production system. Near half of resource inputs in the integrated biogas system are found to be renewable. The renewability and sustainability of the biogas system turn out to be respectively double and six times those of the conventional system. The findings are fully supportive for policy makers in their action towards further progress of biogas project for sustainable development. [ABSTRACT FROM AUTHOR]