Carbon capture and storage (CCS) is broadly recognised as having the potential to play a key role in meeting climate change targets, delivering low carbon heat and power, decarbonising industry and, more recently, its ability to facilitate the net removal of CO2 from the atmosphere. However, despite this broad consensus and its technical maturity, CCS has not yet been deployed on a scale commensurate with the ambitions articulated a decade ago. Thus, in this paper we review the current state-of-the-art of CO2 capture, transport, utilisation and storage from a multi-scale perspective, moving from the global to molecular scales. In light of the COP21 commitments to limit warming to less than 2 °C, we extend the remit of this study to include the key negative emissions technologies (NETs) of bioenergy with CCS (BECCS), and direct air capture (DAC). Cognisant of the non-technical barriers to deploying CCS, we reflect on recent experience from the UK's CCS commercialisation programme and consider the commercial and political barriers to the large-scale deployment of CCS. In all areas, we focus on identifying and clearly articulating the key research challenges that could usefully be addressed in the coming decade.

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Carbon capture and storage (CCS): the way forward

Biomass is a promising renewable energy resource despite its low energy density, high moisture content and complex ash components The use of biomass in energy production is considered to be approximately carbon neutral, and if it is combined with carbon capture technology, the overall energy conversion may even be negative in terms of net CO2 emission, which is known as BECCS (bioenergy with carbon capture and storage) The initial development of BECCS technologies often proposes the installation of a CO2 capture unit downstream of the conventional thermochemical conversion processes, which comprise combustion, pyrolysis or gasification Although these approaches would benefit from the adaptation of already well developed energy conversion processes and CO2 capture technologies, they are limited in terms of materials and energy integration as well as systems engineering, which could lead to truly disruptive technologies for BECCS Recently, a new generation of transformative energy conversion technologies including chemical looping have been developed In particular, chemical looping employs solid looping materials and it uniquely allows inherent capture of CO2 during the conversion of fuels In this review, the benefits, challenges, and prospects of biomass-based chemical looping technologies in various configurations have been discussed in-depth to provide important insight into the development of innovative BECCS technologies based on chemical looping

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Biomass-based chemical looping technologies: the good, the bad and the future

Biomass is increasingly perceived as a renewable resource rather than as an organic solid waste today, as it can be converted to various chemicals, biofuels, and solid biochar using modern processes. In the past few years, pyrolysis has attracted growing interest as a promising versatile platform to convert biomass into valuable resources. However, an efficient and selective conversion process is still difficult to be realized due to the complex nature of biomass, which usually makes the products complicated. Furthermore, various contaminants and inorganic elements (e.g., heavy metals, nitrogen, phosphorus, sulfur, and chlorine) embodied in biomass may be transferred into pyrolysis products or released into the environment, arousing environmental pollution concerns. Understanding their behaviors in biomass pyrolysis is essential to optimizing the pyrolysis process for efficient resource recovery and less environmental pollution. However, there is no comprehensive review so far about the fates of chemical ...

Fates of Chemical Elements in Biomass during Its Pyrolysis

The utilization of renewable energy is significantly important for the world because global energy consumption is increasing, while conventional energy sources are no longer sufficient to meet the energy demand, triggering energy crises. However, variation in solar radiation and wind speed caused by climate and weather conditions restricts the stable operation of renewable energy systems, therefore, causing the output to fluctuate. A hybrid renewable energy (HRE) system can be highly efficient by combining multiple renewable energy sources and is regarded as a promising solution to the above issue. In this review, a comprehensive summary and discussion of the uses of HRE in terms of space heating, cooling, hot water usage, power generation, hydrogen production, drying and multi-generation are conducted. Hybrid system configurations, specific devices, application procedures, and performance are reviewed. Moreover, the challenges and outlook for HRE utilization are discussed, including the following points: proper use of the local sources in view of disperse and regional distribution of renewable energy; development of hybrid storage subsystems for HRE to improve the stability of the energy supply; further optimization of the operation strategy and system size to minimize the cost in order to promote the application; and, clear identification of the supporting local policies of renewable energy, especially considering HRE. Furthermore, the research potential is described for HRE utilization integrating direct CO2 reduction.

Cheng Zhou

Papers

An in-depth assessment of hybrid solar–geothermal power generation

A review on high-temperature thermochemical energy storage based on metal oxides redox cycle

Techno-economic analysis of an integrated liquid air and thermochemical energy storage system

Hybridisation of solar and geothermal energy in both subcritical and supercritical Organic Rankine Cycles

Thermodynamic analysis of a novel hybrid thermochemical-compressed air energy storage system powered by wind, solar and/or off-peak electricity