Identification of Risk Factors Affecting PPP Waste-to-Energy Incineration Projects in China: A Multiple Case Study

School of Civil Engineering and Architecture, Zhejiang Sci-Tech University, Hangzhou 310018, China School of Civil Engineering and Built Environment, Queensland University of Technology (QUT), Brisbane, QLD 4001, Australia School of Art, Architecture and Civil Engineering, Hunan Institute of Technology, Hengyang 421002, China Research Institute of Complex Engineering and Management, Tongji University, Shanghai 200092, China


Introduction
e amount of municipal solid waste (MSW) is constantly increasing in China because of its rapid development of urbanisation and industrialisation in the past three decades and continuous improvement of resident living standards. e annual amount of MSW generated reached 203.6 million tonnes in 2016 [1] and is expected to expand to 220 million tonnes by 2020 [2]. e sharply increased in MSW generation over the years puts pressure on such existing MSW disposal methods such as landfill and compost and resulted in a dilemma of "garbage siege" [3].
Incineration is considered the best way to treat the MSW due to low resource consumption, obvious physical volume reduction, less secondary pollution, and energy-recovery [4][5][6]. Consequently, waste-to-energy (WTE) technology has developed rapidly to provide an effective solution for government to alleviate the pressure of MSW disposal in past decades. WTE incineration in China has developed rapidly since 1988, when Shenzhen built the first WTE plant. According to statistics from the National Bureau of Statistics of China, incinerated MSW increased from 3.70 million tonnes in 2003 to 73.79 million tonnes in 2016, with the number of incineration plants increasing from 47 to 249 over the same period [1,7].
Meanwhile, subject to budget constraints, lack of management capacity, and other factors, it is difficult for the government to construct and operate high-investment, long-term WTE incineration projects alone. To address the increasing need for WTE facilities, the public-private partnership (PPP) arrangement has been widely used to construct and operate WTE incineration projects, taking advantage of the innovation, know-how, flexibility, and financing provided by the private sector [8,9]. In China, more than 70% of WTE incineration projects are now operated and supervised by PPPs, and 108 PPP WTE incineration projects with a total investment of CNY 489 billion were deployed from 2012 to 2016 [8,10].
However, due to the long concession period, involvement of various participants, external uncertainties, and other reasons, PPPs in the WTE incineration industry face more risks than traditional public projects [11][12][13], which a ect their performance and hinder the application of WTE incineration technologies in the MSW disposal industry. In fact, ine ective risk management in the PPP WTE industry has resulted in failure of many incineration projects to reach their expected performance [14,15]. According to risk management theory, risk identi cation is the basis of risk analysis and response and is crucial to the performance of risk management [16,17]. It is therefore essential for both government and WTE private sector investors to have a clear understanding on the risks involved in PPP WTE incineration projects and to establish suitable responsive strategies accordingly.
Nevertheless, although there is ample literature concerning PPP risk identi cation and analysis, very little is related to the identi cations of risk factors a ecting PPP WTE incineration projects. Most PPP studies have been conducted to identify risk factors in such other industries as transportation [18], water supply and treatment facilities [19], energy facilities [20], and medical facilities [21]. In addition, the identi ed critical risk factors of PPP WTE incineration projects vary signi cantly between countries because of their unique social-economic environments, policies, and regulations [14,22]. In China, Song et al. [4] and Xu et al. [23] have identi ed the critical risk factors a ecting PPP WTE projects through case studies. However, the cases involved are insu ciently representative to re ect the status of China's PPP WTE industry because their risk events occurred before 2012, when the central and local governments introduced a series of new policies and regulations related to the PPP WTE industry [24].
In response, we conducted a multiple case study to identify the risk factors a ecting PPP WTE incineration projects in China over the past decade. e results pave the way for the risk analysis, allocation, and response of PPP WTE incineration projects and are expected to shed light on their performance improvement as well as the development of the PPP WTE industry throughout the country.

Research Methods
e research methods used in this study comprise a comprehensive literature review and multiple case studies. e ow of the overall research framework is shown in Figure 1. 2.1. Literature Review. As the most commonly used method of risk identi cation, risk checklists depend on historical data and experience to list the risk factors of similar projects in a logical order [25]. Accordingly, the literature review provides an auxiliary method of building a risk checklist favoured in many studies [26][27][28][29] and is thus conducted here to identify the general risks involved in China PPP WTE incineration projects. e acronym "PPP," which is used to speci cally represent the noun "public-private partnerships," is mentioned in the literature in a variety of forms [2,30], such as publicprivate partnerships (PPP), build-operate-transfer (BOT), private nance initiative (PFI), and design-build-nanceoperate (DBFO). erefore, in order to ensure integrity and accuracy, a keyword search process was conducted using the schema of TITLE-ABS-KEY ("public private partnership" OR "build operate transfer" OR "private nance initiative" OR "design build nance operate" OR "PFI" OR "BOT" OR "PPP" OR "DBFO") and TITLE-ABS-KEY ("risk"). From the literature retrieved in this way from selected databases or journals, articles with clear gures, tables, or text descriptions of the identi ed risk factors were chosen for further content analysis. is involved a total of 54 articles, including 16 Chinese articles and 38 English articles. e most simple and e ective method of identifying risk factors is to establish a risk checklist [31]. is was created in three steps: (1) the risk factors related to PPP infrastructure projects were identi ed through a comprehensive literature review; (2) these were carefully examined by deleting the inherent risk factors of some categories of PPP projects, for example, the safety risk in PPP highway projects caused by overload and combining risk factors with the same meanings but using di erent terms; and (3) the risk checklist was established with a clear hierarchical structure through a synthesised risk classi cation drawn from the literature.
Based on the comprehensive literature review, the risk checklist composed of 54 risk factors was established (Table 1).
is follows the classi cation method of PPP risk factors proposed by Li et al. [26], where the risk factors are divided Step 1: risk checklist for PPP infrastructure projects Step 2: risk factors affecting PPP WTE incineration projects Literature review Discussion and conclusion Multiple case study  Advances in Civil Engineering into three levels, that is, macrolevel, mesolevel, and microlevel. According to Li et al. [26], macrolevel risks refer to the risks outside the project, mesolevel risks refer to the risks within the project, and microlevel risks refer to the risks of the relationship between stakeholders.

Multiple Case Studies.
e present study aims to identify the "what" and "how" risk factors affecting PPP WTE incineration projects in China. Case studies are appropriate to answer such questions [32]. Meanwhile, PPP WTE incineration projects are still in their infancy in China and  [33].
Moreover, a single case study is contextually stronger and is not conducive to summarising general rules and promoting the research results [34]. As a result, a variety of case studies are used to provide a range of contexts. e flow of the multiple case studies comprises the following four steps: (1) Determining Standards for Case Selection: in order to fully reflect the current status of China's WTE industry and to ensure the comprehensiveness and representativeness of the cases, the criteria for case selection are as follows: (1) the WTE incineration projects are operated by PPP arrangement, such as BOTand DBFO; (2) risk events significantly that affect their performance occurred during the project lifecycle; and (3) except for some typical and significant cases, the risk events involved occurred after 2012. (2) Case Selection and Data Collection: the systematic analytic process for case selection followed [35]. First, a wide range of sizable samples of actual WTE incineration plants that were heavily affected by the occurrence of a variety of risk events were collected from the literature, research reports, newspapers, and the Internet. Second, a total of 35 cases, which is far more than the usual requirement for multiple case studies [33], were selected as study cases to identify the critical risk factors by using the criteria for case selection determined above. ird, detailed information relating to these selected cases was collected from the Internet, industrial reports, media, academic literature, and other relevant materials, and a desk research of collected data was conducted to prepare materials for the upcoming content analysis. Table 2 provides details of the cases.
(3) Identifying Risk Factors through Content Analysis: as an observational research method to evaluate the symbolic content of all forms of materials, either qualitative or quantitative content analysis is frequently used to identify the major facets of a set of data [36]. us, content analysis was carried out to identify the risk factors appearing in each of selected cases by utilizing the preferred risk checklist established from the literature review. (4) Verifying the Identified Risk Factors by Expert Interview: interviews with a preestablished team of experts were conducted to verify the appropriateness and comprehensiveness of the identified risk factors. e team consists of three experts with different WTE industry backgrounds-a Hangzhou governmentrelated WTE industry official, a senior manager from a WTE incineration plant (Hangzhou Green Energy Environmental Protection Power Co., Ltd), and a researcher related to WTE implementation.

Results
e identified risk factors seriously affecting the performance of each case are summarised in Table 3. Table 4 summarises the frequency of the risk factors identified in the case studies, divided into high-, medium-, and low-frequency risks. e high-frequency risks (appearing in at least 10 of the 35 cases) comprise public opposition risk, environmental pollution risk, government decision-making risk, defective legal and regulatory system, and MSW supply risk and may heavily affect the performance and development of the WTE incineration industry in China. Mediumfrequency risks refer risk factors of the frequency from 4 to 10,     Due to Hankou's rapid urbanisation, the plant was getting closer to the populated residential and commercial areas. e incinerators were not equipped appropriately. In 2014, the local residents protested against the plant because it has caused serious environmental pollution. In the same year, the project was fined by the local government because of illegal disposal of carbon monoxide and fly ash. Finally, the plant was closed and will be rebuilt on another site

Discussion
Similar to previous studies identifying risk factors in the WTE incineration industry, the results in Table 4 indicate that numerous risk factors affect the performance the PPP WTE incineration plants and the development of PPP WTE incineration industry in China. On the one hand, although the conclusions of previous studies are not entirely consistent, they provide sufficient evidence that the performance of PPP WTE incineration projects is heavily affected by critical risk factors such as environmental pollution, government decision-making, public opposition, and MSW supply [4,23]. On the other hand, emerging factors such as safety and government behaviour risks are unexpectedly identified. e reason may be attributed to the fact that low-frequency risks are easily overlooked, especially when those related to local community health and the environment occurred at the same time [37][38][39]. Moreover, different studies provide different rankings of the importance of the risks. Some argued that the vital factor affecting the development of PPP WTE incineration projects is not technical problems but deficiencies in government regulations and enforcement [40,41]. Cheung and Chan [42], for example, concluded that government intervention and public credit are severe risks for PPP WTE incineration projects. In contrast with previous studies,  10 Advances in Civil Engineering however, our results indicate public opposition risk to be the highest, followed by traditional critical risk factors such as environmental pollution, government decision-making, the defective legal and regulatory system, and MSW supply risks. ese are further analysed in the following.

Public Opposition Risk.
e most important reason for public opposition is the emerging "not in my back yard" (NIMBY) syndrome [14], which sometimes manifests in violent behaviour [43]. WTE facilities can be seen as one kind of LULU (locally unwanted land use), of which the benefits are usually broadly distributed, while most of the costs tend to be localised [44,45]. WTE facilities face considerable and strong opposition from the local communities in which they are situated because they have potential negative impacts (e.g., smell and dioxin release) on local residents' environments, health, or even property [14,46]. Protests against incinerators, or antiincinerator campaigns, have been documented in many countries/regions worldwide [47,48]. Recently, NIMBYism has become very popular in many potentially hazardous industries in China, especially the WTE industry that, as Table 3 clearly indicates, has led to many WTE projects being cancelled, suspended, or closed before the scheduled closure date. According to public information statistics, at least 10 NIMBY movements related to PPP WTE incineration projects occurred since 2013, for example, the Guangdong Huizhou WTE incineration plant, the Hangzhou Jiufeng WTE incineration plant, and the Nanjing Liuhe WTE incineration plant [49].
Disputes over site selection and decision-making of WTE incineration plants are regarded as the main reason for public opposition [14]. Inadequate disclosure of related information, as well as the inefficient governance and regulation from local governments, are other critical causes by which, once problems occur, it will not only result in a significant loss but also deepen public distrust of the government and PPP WTE incineration projects [49,50]. Moreover, compensation should also be taken into account [51,52] for the reason that everyone is highly unlikely to sacrifice their own interests (health and wealth) without adequate compensation [49], with economic compensation considered an effective solution to NIMBY protests [53]. Furthermore, insufficient risk communication between local governments, WTE enterprises, and local communities is also often a significant issue behind public opposition [48,50].

Environmental Pollution Risk.
Environmental pollution risk occurred in 20 of 35 cases. e collection, delivery, treatment, and incineration of MSW involve complex physical, chemical, and biological processes and can lead to a several forms of environmental pollution [54,55]. Flue gas from waste incinerators, for instance, contains acid gases, heavy metals, dioxins, and other toxic and hazardous pollutants [23,24] that cannot be completely eliminated [56]. Waste leachate is another significant source of pollution, and it lacks a mature and reliable treatment technology in China [24]. As happened in Cases 2 and 11, garbage spillage and leakage in MSW collection, delivery, and transportation can also lead to secondary environmental pollution [57]. Consequently, equipment, materials, and technologies for pollution prevention and control need to be used to minimise negative impacts on the environment, which significantly increased WTE operating costs [4,24]. As one of the most common "negative impacts" of PPP WTE incineration projects, environmental pollution is often caused by the unethical behaviour of practitioners during the construction and operation stage [58], such as through the excessive discharge of contaminating materials and hazardous substance leaks [4], as illustrated in Cases 27 and 33. China's defective legal and regulatory system, which provided the loophole for private sector's illegal activities, may be the main contributing reason [58,59].

Government Decision-Making
Risk. Government decisionmaking risk is often manifested as inappropriate site selection in the field of WTE incineration, which heavily affects the implementation of WTE incineration technologies in the MSW disposal industry [60], as shown in Cases 8, 16, and 24. As one kind of LULU, site selection and government decisionmaking related to PPP WTE incineration projects involve not only technical issues but also a complex mix of economic, social, and environmental concerns such as perceived risk and public distrust [61,62]. us, an open and consultative decision-making approach with public participation and transparency is seen as an effective way to ensure the reliability and fairness of the government's decision-making approach [48,61,62]. However, although cultivating a strong environmental state remains a key part of China's environmental management strategy, the emerging government decision-making risks indicate that the traditional top-down decision-making approach and the command and control regulation are insufficient to deal with the NIMBY syndrome in the WTE industry [47,[63][64][65][66]. In addition, it is worth noting that almost all highly protested WTE projects in China are eventually cancelled or indefinitely postponed by the local governments because the local governments will circumvent unrest through increasing opacity or by selecting sites in locations where public opposition is less likely to emerge [64,65].

Defective Legal and Regulatory
System. Delivering sustainable PPP WTE incineration projects requires a good supportive legal and regulatory environment [26]. However, the legal and regulatory framework for PPPs, especially for PPP WTE incineration projects in China, is still in its infancy [67,68]. As a new waste disposal approach, incineration technologies have not been widely used in China's MSW disposal industry until recently, despite the first WTE incineration plant in China being built in Shenzhen in 1988. us, many relevant laws and regulations that relate to their establishment and improvement are far less than perfect. For example, the price system of power generation with WTE incineration was basically chaotic until 2012, when the National Development and Reform Committee published a regulation entitled e Notice on Improving the Price Policies of the Municipal Solid Waste Incineration for Power Generation (2012) in which the conversion coefficient from MSW to gridconnected power was temporarily determined to be 280 kWh/t and the price of grid-connected power is 0.65 CNY/kWh. is led to the excessive use of traditional energy sources such as coal and diesel fuel in many WTE incineration plants to obtain high benefits from electricity generation. Meanwhile, this risk may also rely on existed legislation and regulations being poorly carried out or even not enforced at all [4,42], resulting in illegal acts such as excessive pollutant discharge and use of outdated technologies, as shown in Cases 7, 14, 16, and so on. In addition, transparency and open decision-making approaches are essential for establishing a good legal and regulatory framework, or WTE operators may violate the technical and safety standards for their own interests [69]. Finally, frequent changes in legislation are also a major cause of legal and regulatory risks, such as laws relating to land use, tax, labour, and environmental protection [70,71].

MSW Supply Risk.
In contrast with other risks such as public opposition and environmental risk, the MSW supply risk is a specialised WTE incineration project risk. e inadequate quantity and/or quality of MSW supply are two aspects of MSW supply risk [4]. An inadequate MSW supply will affect the efficiency of PPP WTE incineration projects, both economically and technically. On the one hand, the inadequate supply of MSW caused machines to be idle or to be used interchangeably, which can lead to financial loss and reduced revenues because both disposal fees and electricity fees depend on the amount of waste disposal [23]. On the other hand, a serious shortage of MSW supply may cause incomplete MSW incineration, which leads to incineration gas leakage. In terms of quality, MSW with high moisture content and low calorific value cannot be burned directly [59,72]. If the MSW is of poor quality, the incineration of waste will require auxiliary fuels, such as coal and diesel, which will not only increase operating costs but also lead to equipment damage [23,73].
Moreover, compared with similar studies by Song et al. [4] and Xu et al. [23] in China, the current study contributes to the identification of PPP WTE incineration project risk factors by a more comprehensive set of cases as shown in Table 5. e comparative analysis between the three studies shown in Table 5 reveals that the identified risk factors changed with improvements in China's political, economical, and social conditions. Consistent with the findings of Song et al. [4] and Xu et al. [23], a variety of economical, social, environmental, and legal risk factors significantly affecting PPP WTE incineration projects in China have also been identified in the current study (including environmental pollution risk, defective legal and policy making, opaque government decision-making, and insufficient and nonlicensed MSW supply) in spite of the rapid growth in WTE incineration implementation during the past decade.
Meanwhile, the rankings of the significance of these identified risk factors are different. In particular, due to rising public environmental awareness and an increasing emphasis on public health along with improvements in the economic conditions and living standards in China [14,50], public opposition is increasingly becoming a key risk factor affecting the development of the PPP WTE incineration industry. At the same time, the ranking of MSW supply risk has relatively decreased since 2013. is is because the rapid urbanisation in China had resulted in a sharp increase in MSW generation and the central and local governments had issued a series of orientations and regulations to stress the significance of classification in the disposal of harmless and recycled MSW [74][75][76], by which the quality of MSW is significantly improved [10].
Moreover, some critical risk factors identified in the studies of Song et al. [4] and Xu et al. [23], such as technical risk, payment risk, and government credit risk, have gradually faded out in recent years. e possible reason is that some interim issues, such as government budget deficit and immature incineration technologies, have been gradually resolved with the continuous development of China's social and economic conditions. For example, the percentage of grate furnaces (advanced incineration technologies [10,77] and widely used in Europe, USA, and Japan) adopted in incinerators in China is about 64%, a figure predicted to increase constantly because of the localisation of the technology and policy support [10].

Conclusion
In light of the pivotal role that risk identification, analysis, and response play in the successful development of PPP WTE incineration projects, we conducted a multiple case study to identify the risk factors in China by drawing on the experience and lessons learn from the real-life risk events of 35 PPP WTE incineration plants through content analysis and expert interviews. e results provide a solid foundation for the further risk analysis, allocation, and response of PPP WTE incineration projects. Both researchers and practitioners of the PPP WTE incineration industry in China, including policy makers, WTE professionals, and academic researchers, may benefit from this study by referring to the identified risk factors in policy making, operating performance improvement, critical risk response, and so on. us, the present study is expected to shed light on their improvement in performance as well as the development and implementation of WTE incineration technologies in China's MSW disposal industry.
Based on a comprehensive analysis of the 35 selected cases, 18 risk factors affecting PPP WTE incineration projects in China are identified. e findings reveal that the performance of China PPP WTE projects is most affected by public opposition, environmental pollution, government decision-making, the defective legal and regulatory system, and MSW supply risks.
Although the current study contributes to the literature on the management of the PPP WTE industry and PPP infrastructure projects by identifying the risk factors affecting PPP WTE incineration projects in China, it also has some limitations that need to be addressed by further research. First, due to the limitation of case selection, there are undoubtedly other risk factors involved that are expected to be examined by further studies. Second, although multiple case studies were used in the current research, the identification of risk factors for each case was still based on the subjective judgment of experts, and future validation studies are needed using such quantitative or empirical research methods as case-based reasoning technologies and statistical analysis.

Data Availability
e data used to support the findings of this study are available from the corresponding author upon request.

Conflicts of Interest
e authors declare that there are no conflicts of interest regarding the publication of this paper.