Prospects of carbon capture and storage (CCS) in China’s power sector – An integrated assessment

Highlights

• In this study an integrated approach is chosen to assess CCS in China.

• Five different assessment dimensions are covered.

• Several conditions need to be fulfilled if CCS is to play a future role in China.

• The most crucial requirement is a reliable storage capacity assessment for China.

• Further requirements are economic viability, ecological impacts and public support.

Abstract

Objective: The aim of the present article is to conduct an integrated assessment in order to explore whether CCS could be a viable technological option for significantly reducing future CO₂ emissions in China. Methods: In this paper, an integrated approach covering five assessment dimensions is chosen. Each dimension is investigated using specific methods (graphical abstract). Results: The most crucial precondition that must be met is a reliable storage capacity assessment based on site-specific geological data. Our projection of different trends of coal-based power plant capacities up to 2050 ranges between 34 and 221 Gt of CO₂ that may be captured from coal-fired power plants to be built by 2050. If very optimistic assumptions about the country’s CO₂ storage potential are applied, 192 Gt of CO₂ could theoretically be stored as a result of matching these sources with suitable sinks. If a cautious approach is taken, this figure falls to 29 Gt of CO₂. In practice, this potential will decrease further with the impact of technical, legal, economic and social acceptance factors. Further constraints may be the delayed commercial availability of CCS in China; a significant barrier to achieving the economic viability of CCS due to a currently non-existing nation-wide CO₂ pricing scheme that generates a sufficiently strong price signal; an expected life-cycle reduction rate of the power plant’s greenhouse gas emissions of 59–60%; and an increase in most other negative environmental and social impacts. Conclusion and practice implications: Most experts expect a striking dominance of coal-fired power generation in the country’s electricity sector, even if the recent trend towards a flattened deployment of coal capacity and reduced annual growth rates of coal-fired generation proves to be true in the future. In order to reduce fossil fuel-related CO₂ emissions to a level that would be consistent with the long-term climate protection target of the international community to which China is increasingly committing itself, this option may require the introduction of CCS. However, a precondition for opting for CCS would be finding robust solutions to the constraints highlighted in this article. Furthermore, a comparison with other low-carbon technology options may be useful in drawing completely valid conclusions on the economic, ecological and social viability of CCS in a low-carbon policy environment. The assessment dimensions should be integrated into macro-economic optimisation models by combining qualitative with quantitative modelling, and the flexible operation of CCS power plants should be analysed in view of a possible role of CCS for balancing fluctuating renewable energies.

Introduction

Carbon capture and storage (CCS) for reducing carbon dioxide emissions from fossil fuel-fired power plants and industrial sources is the subject of intensive global debate. CCS is considered a technology option that could contribute significantly to achieving the objective of decreasing greenhouse gas (GHG) emissions by 50–85% by 2050 [1]. This radical reduction is imperative in order to prevent the rise in global average temperature from exceeding a threshold of 2 °C above preindustrial times by 2100 [2]. For the time being, however, unabated use of coal is on the rise [3]. This development is mainly driven by coal-consuming emerging economies that are experiencing a rapidly growing demand for energy. The aim of the present article is to explore whether CCS in the power sector could be a viable low-carbon option for China, which is one of these key countries. Although coal consumption in China seems to have flattened since 2014 [4] following a steady increase for years [3], CCS may be necessary in China to enable the country to meet the long-term climate protection target of the international community to which China is increasingly committing itself [5]. A corresponding analysis for India has already been provided [6]; the case of South Africa will be presented in a separate publication.

In China, CCS has been discussed intensively, mainly by focusing on the concept to combine capture with the use of CO₂ (CCUS) for enhanced oil (EOR) or gas recovery (EGR). However, if a strong GHG reduction is required and CCS is deemed to be a key reduction strategy, CO₂ will also have to be sequestered in other formations. Thus, an important aspect for assessing CCS is knowing whether China has adequate storage capacity [7]. Our main research question is therefore to estimate how much CO₂ can potentially be stored securely in the long term in geological formations and to determine the relation between this storage potential and the potential required. Further research questions involve estimating when CCS technology could become commercially available, evaluating the costs involved and the ecological implications and stakeholder positions towards CCS. The present article does not aim to elaborate the role CCS could play in a future sustainable energy system in China compared to other low-carbon technology options such as renewable energies. Although this question is highly challenging, this article focuses on a sound analysis of CCS by providing the basis for a future comparative assessment.

To our knowledge, no assessment with a comparable comprehensive scope has been published before. As an analysis of peer-reviewed literature illustrates, CCS in China started gaining interest in 2007/2008, when publications first mentioned CCS as a possible mitigation measure in coal-consuming countries (Fig. 1). While articles with a more general view on CCS peaked in 2009, the number of publications that explore the challenges of both CO₂ capture in the power sector and CO₂ storage grew from 2009. There were therefore very few one-dimensional assessments, most of which focused on public acceptance and life cycle analysis (LCA). An increasing number of authors refer to the uncertainties and challenges faced by CCS, such as increased energy and water consumption, inadequate storage capacities or potential CO₂ leakages, which could hamper the large-scale deployment of CCS [8], [9], [10], [11]. Several authors pursued a more systems analytical approach from around 2009. They developed long-term energy scenarios, exploring the role played by CCS in a macro-economic optimised environment (for example, in [12], [13], [14], [15], [16], which modelled the Chinese energy system; in [17], [18], [19], [20], which analysed China as part of long-term energy scenarios for Asia, and in [8], [21], [22], [23], which modelled China as one of several regions within world energy models). In addition, roadmaps for CCS such as in [24], [25] or strategic issues and policy measures such as in [26], [27], [28] were explored. However, these sources do not include different assessment dimensions in their roadmaps, resulting in an integrated view; nor do they attempt to scientifically verify the storage capacities that are implicitly assumed as the basis for their assessment. The only exception is [29], which developed a six-dimensional indicator set for evaluating different low-carbon technology pathways, albeit without considering important dimensions such as storage capacity and public acceptance. Our article therefore aims to close this gap by providing a holistic, long-term analysis of the potential role of CCS in China.

In this paper, we first describe the methodologies applied in the individual assessment aspects of the study (Section 2). The outcome of each assessment step is given in Section 3. Subsequently, we combine the assessment dimensions to present an overall result from an integrative perspective (Section 4). We close with an outlook on the needs for further research (Section 5).