The Evolution of Biodiesel Policies in China over the Period 2000–2019

: The Chinese government launched policies supporting biodiesel production and innovation to meet sustainable energy demands under rapid economic and social development. This study systematically investigates the dynamic transitions of biodiesel policies in China regarding policy contents and policy networks. We performed a content analysis in this study and used NVivo12 software to support the analysis process. The results highlighted some issues. First, the Chinese government supported the development of biodiesel from multiple policy objectives and adopted various policy instruments, eventually transforming biodiesel in China from the ﬁrst- to second-generation. Second, the State Council was the main institution to promote biodiesel policies, and the National Development and Reform Commission under the State Council burdened most of the responsibilities of policy implementation. Most of the policies were issued at a lower level of administration rather than a higher level of decision-making. Biodiesel policies in China were gradually detailed, and they constantly established a system of technology and product innovation.


Introduction
Biodiesel reduces using fossil fuels and considerably decreases the emissions of greenhouse gases (GHG) and became significant for renewable energy [1][2][3][4]. First-generation biodiesel, currently in widespread production, is derived from various feedstocks, such as used cooking oil, and second-generation biodiesel, only a few of which are close to large-scale commercialization, is derived from multiple feedstocks and refining technologies, such as algae [5,6]. Since the United Nations Framework Convention on Climate Change in 1992 revealed the principle for the transformation to more sustainable modes of production and consumption, the Kyoto Protocol, which came into force in 2005, required Annex I countries (mostly developed countries) to reduce their GHG emissions to 5% below the levels of 1990. Once the Kyoto Protocol ends in 2020, the Paris Agreement, which came into force in 2016, should continue strengthening the global response to the threat of climate change and keep the global average temperature well below 2 • C above preindustrial levels. Under this agreement, both developed and newly industrialized countries were required to submit emissions reduction targets based on their nationally determined contributions [7]. Therefore, national governments globally accelerated the production and innovation of biodiesel as a solution for reducing GHG emissions [8][9][10][11][12].
China, as one of the newly industrialized countries, launched policies to support biodiesel production and innovation to meet sustainable energy demands under rapid economic and social development [13,14]. This article evaluates biodiesel policies according to the research, technology, development, and innovation (RTDI) policies of biodiesel. Technological Policy of Pollution Control for Diesel Vehicles, introduced in 2003, revealed the starting point at which China's government

Research Method and Analysis Processes
This study adopted content analysis as a research method. As described by Elo and Kyngas [18], content analysis is a widely used qualitative research method, and it conceptually describes the empirical phenomenon. Since we want to explain the empirical experiences of China's biodiesel policies based on the fundamental concepts of policy analysis, content analysis is a suitable research method for our study. Following Elo et al. [19], to improve the trustworthiness of a content analysis study, researchers should scrutinize the indications at every phase of the analysis process, including the preparation, organization, and reporting of results. The preparation phase must identify the trustworthiness of the data collection and sampling strategy, the organization phase is concerned with the categorization and interpretation and the reporting phase should report the results systematically and logically. We display the analysis processes of the preparation and organization phases in this section, and we further show the results in Sections 3 and 4.

Data Collection and Sampling Strategy
First, we collected data by searching for the official websites of the institutions within the central government. These websites included the Communist Party of China Central Committee, the National People's Congress (NPC), and the State Council and its subordinate ministries, including the National Development and Reform Commission, Ministry of Finance, and Ministry of Science and Technology. We obtained publicly promulgated policies since the reform and opening in the 1970s addressing the development of biodiesel by backtracking and searching for the relevant contents in the literal materials and policy texts. Since relatively fewer policies related to specifically biodiesel exist, our search terms included biodiesel and other related terms, such as bioenergy, renewable energy, new energy, We purposively sampled our data, ensuring the correctness of the selected policies and rigorously shifted through 63 policies following two principles. First, only the documents whose main contents or at least a part of the contents are closely related to the development of biodiesel were selected. Second, the policy must be a legislative document or a normative document that was officially issued by the government, such as laws, plans, opinions, and notices. We identified 45 samples of effective policies (Table 1).
After we collected policy documents concerning the development of biodiesel in China, we organized the policy texts of 45 policies following the analytical framework originally established by Bai et al. [20]. The policy texts were reviewed by considering three dimensions, namely the dates of policy promotion, the structural hierarchy, and policy types ( Figure 1). The policy promotion dates were mainly used to analyze the transitions of policy objectives and policy instruments, and they were divided into different periods, which will be further examined in Section 3. A structural hierarchy was adopted to express the changes of policy networks and displayed the longitudinal governance frameworks for decisions and the implementation of biodiesel policies. Furthermore, policy types were used to analyze the levels between policies, deepening the analysis of policy evolution, and changes of policy networks over time. The analytical framework in practice laid the foundation for the later encoding of policy texts. We purposively sampled our data, ensuring the correctness of the selected policies and rigorously shifted through 63 policies following two principles. First, only the documents whose main contents or at least a part of the contents are closely related to the development of biodiesel were selected. Second, the policy must be a legislative document or a normative document that was officially issued by the government, such as laws, plans, opinions, and notices. We identified 45 samples of effective policies (Table 1).
After we collected policy documents concerning the development of biodiesel in China, we organized the policy texts of 45 policies following the analytical framework originally established by Bai et al. [20]. The policy texts were reviewed by considering three dimensions, namely the dates of policy promotion, the structural hierarchy, and policy types ( Figure 1). The policy promotion dates were mainly used to analyze the transitions of policy objectives and policy instruments, and they were divided into different periods, which will be further examined in Section 3. A structural hierarchy was adopted to express the changes of policy networks and displayed the longitudinal governance frameworks for decisions and the implementation of biodiesel policies. Furthermore, policy types were used to analyze the levels between policies, deepening the analysis of policy evolution, and changes of policy networks over time. The analytical framework in practice laid the foundation for the later encoding of policy texts.

Content Encoding and Categorisation
The analytical categories were organized according to our research questions. As suggested by Hsieh and Shannon [21], a directed approach to content analysis is to validate or extend existing theory or research. Researchers begin coding by identifying key concepts or variables that construct the research questions. While the analytical categories are established depending on the research questions, the operational definitions for each category should be determined based on existing theory or research. Following the suggestions of Hsieh and Shannon [21], we established our analytical categories in two steps. First, we searched for categories based on existing literature. As described by Sabatier and Mazmanian [22] and Howlett [23], the transitions of policies included the evolution of policy objectives and policy instruments. Since our first research question explored the transitions of biodiesel policies in China, we began to search for the proper terms presenting the policy objectives and policy instruments of biodiesel. Second, the RTDI policies of renewables frequently supported biodiesel as a type of renewable energy. The common policy objectives for the development of renewables in most countries, as narrated by Ramos et al. [11], Lipp [24], Horst [25], Winzer [26], and Naylor and Higgins [27], included environmental sustainability, energy supply continuity, industrial development, technology innovation, and rural development. Moreover, following Linden et al. [28], Carley [29], Liao [30], and Amstalden et al. [31], the economic measures (financial support and market configuration) and administrative measures (standard control) were frequently-implemented policy instruments in all governments, aiming at supporting renewable energy projects. Therefore, we adopted the categories referring to economic and administrative policy instruments. Each category, as suggested by Hsieh and Shannon [21], was defined based on existing literature. Table 2 shows the operational definitions for each category.

Analysis Category Definition
Policy objectives

Environmental Sustainability
Reduction of GHG emissions, and use biodiesel to replace fossil fuels for environmental protection and climate neutrality [11,24,25].

Energy Supply Continuity
Expectation that energy supply could be achieved through energy diversity, the deployment of renewables as substitutes for gas or oil [25,26].

Industrial Development
Growth of the industry in the market [25], or creation of new industry that can lead to job creation and find increasing market to serve [24].

Technology Innovation
Foster innovation and commercialization of technologies, which are exportable, and the provision of employment [24,25].

Rural Development
Stimulate the development of dynamic, competitive and sustainable economies in the countryside and tackle poverty in rural areas [24,25].

Financial Support
The support for relevant market players to generate desired economic behaviors, including fixed feed-in tariffs, investment subsidies, tax emptions for production costs, and fees or grants for technology innovation [32].

Standard Control
The provision of the regulatory environment, which forced market players by laws or policies to encourage the set of behaviors defined acceptable for the state authority. These regulations include technology standards, safety standards and production stops, as well as the technology bands for long-term contracts at a fixed price [27].

Supervised Evaluation
Evaluation for the permits of market players who have been licensed and active in the market, as well as the review for the effects and effectiveness of policy instruments [24].

Legal Liability
Punishment for deviant behaviors with negative sanctions, such as a fine, restrictions of trade, and prohibitions [28].

Market Configuration
Built up a market segment for renewable energies through the establishment of new marketing channels, such as the expansion of footholds [32].

Sample Engineering
Encouragement for the construction of a significant number of new renewable energy power plants or factories through the direct investments of the government [32].

Infrastructure
The government establishes R&D labs or other projects, which improve electrical testing and the certification system [30].
Once they were decided, we allocated a code to each category and used the pre-examined codes to encode the 45 selected samples. Table 3 shows the codes from A to L, which were given to match each of the 12 analytical categories. While the codes from A to E revealed the analytical categories of policy objectives, the codes from F to L represented the policy instruments. Table 3 also shows the calculation of the frequency of these codes in the three periods using the software of NVivo12. Figure 2 shows a two-dimensional distribution map of the policy texts, and Table 4 shows the embeddedness of the analysis codes of each policy document. As shown in Figure 2 and Table 4, the texts of 45 policy documents were illustrated following the format of document number-chapter number-clause number. The document number is the number allocated to each policy in Table 1, and the chapter number refers to the appearance of biodiesel in the chapters of each policy document. Moreover, a clause number examines the appearance of biodiesel in the clauses of each chapter. For example, the Renewable Energy Law in 2005 was labeled as Number 1 in Table 1. As Clause 16 of Chapter 4 of the Law appeared in Code B (Energy Supply Continuity), Code G (Standard Control) and Code J (Market Configuration) regarding biodiesel development, the format given to the Renewable Energy Law in Table 4 was 1-4-16BGJ. In Figure 2, the format given to the Renewable Energy Law under Code B, Code G, and Code J in the first period was 1-4-16.    9-1-3B; 9-3-2ABDEC; 9-3-2DJBK; 9-3-2E; 9-5-1I; 9-5-2F; 9-5-3J; 9-5-4CD

Results of Policy Transitions
We  Table 5 displays the annual production of biodiesel in China. The policy transitions are further discussed below. Table 5. Annual production of biodiesel in China.    (Table 2) concentrated on energy supply continuity (14.43%), technology innovation (13.46%), and environmental sustainability (11.54%). Technology innovation, as guided by the law and other policies, focuses on first-generation biodiesel produced from used cooking oil, waste animal, and vegetable oils and non-edible energy crops. For example, the Notice on Issuing the Catalogue of Comprehensive Utilization of Resources issued in 2004 gave tax exemptions for the supply of biodiesel produced from waste animal and vegetable oils. Furthermore, the Opinions on the Implementation of Fiscal and Taxation Support Policies for the Development of Bioenergy and Biochemical issued in 2006 also subsidized the cultivation of non-edible energy crops, such as tung tree and Pistacia chinensis.

Calendar Year Production (Million Liters)
The policy instruments complemented the policy objectives. Financial support (15.38%) was the most frequently used policy instrument in the period. Financial support included subsidies, tax exemptions, and loans with low-interest rates for the individuals and private companies that invested in the production and innovation of biodiesel. Farmers' cultivation of non-edible energy crops was also subsidized. Standard control (8.65%) regulated the technical norms adopted for the production of biodiesel. Sample engineering (6.73%), which was fully funded by the government but operated by private companies, was constructed near the origins of non-edible energy crops to represent the standard processes of biodiesel production. In the first period, as biodiesel only initially emerged in China (Table 5), policies emphasized the increase in the supply of biodiesel. As the policy objectives aimed to encourage technological innovation of biodiesel to fulfill the visions of energy supply continuity and environmental sustainability, the policy instruments of financial support, standard control, and sample engineering were used to encourage private involvement in the standard production of biodiesel. However, as the industry of biodiesel only initially germinated, the policy instruments, shaping the market demands of biodiesel, such as market configuration, were supplementary at the time.

Initial Inclusion within the National Industrial and Energy Plan (Mid-2007 to 2011)
The 11th Five-Year Plan for the Development of Biological Industry in mid-2007 included biodiesel in the long-term national plan for the first time. As a general industrial plan for biotechnology-related industries, biodiesel was a new industry based on biotechnology and supported biopharmaceuticals to contribute to biotechnology innovation of the country. The National Development and Reform Commission was the sole ministry to implement the long-term plan and encouraged first-generation biodiesel by subsidizing the cultivation of non-edible energy crops and process innovation of used cooking oil. Afterward, the 11th Five-Year Plan for the Renewable Energy issued in 2008 further included biodiesel in the long-term national plan of renewable energies, and it supported biodiesel along with wind and solar energies. The National Development and Reform Commission, which implemented the long-term energy plan, recognized biodiesel as part of renewable energy that contributes to energy supply and environmental sustainability. Additionally, the Commission announced the first detailed landmark that, by 2010, the annual production capacity of biodiesel should reach 200,000 tonnes, most of which should be made by non-edible energy crops, including Jatropha curcas, tung tree, and Pistacia chinensis. Next, the policy objectives of the 16 policies launched from mid-2007 to 2011 emphasized energy supply continuity (15.79%) and technology innovation (12.28%). However, as biodiesel was considered part of biotechnology-related industries, the priority of industrial development (12.28%) increased, while environmental sustainability (7.02%) continued to be a critical objective for the development of biodiesel ( Table 2). The technological innovation of biodiesel focused on first-generation biodiesel produced from used cooking oil and non-edible energy crops. However, the Chinese government gradually noticed the establishment of the innovation system of biodiesel and encouraged technology transfer from universities to industry rather than solely supported technology innovation within the industry. For example, the 12th Five-Year Plan for Science and Technology Development, launched in 2011 by the Ministry of Science and Technology, established innovation systems of new energy technologies, including biodiesel.
The policy instruments were implemented to fulfill the policy objectives. Financial support (12.28%) was still the most frequently used policy instrument, allocated to universities as research funding and private companies through subsidies and tax exemptions. Since industrial development emerged as a critical policy objective, market configuration (8.77%) was adopted as an essential policy instrument to expand the points of sale for biodiesel. As the involvement of private companies in the production of biodiesel increased, legal liability (7.02%) was strengthened to impose fines for unqualified biodiesel products sold in the market. Furthermore, standard control (5.26%) revealed the minimum quality of biodiesel products, and sample engineering (7.02%) was used to represent the standard processes of biodiesel production. In other words, policy instruments were synthetically operated to establish the overall system of biodiesel innovation and production. As the outputs of biodiesel increased and the market for biodiesel gradually formulated, policy instruments were used to control the supply of biodiesel through financial support, standard control, and sample engineering and to shape market demands by market configuration and legal liability.

The Embeddedness within National-Specific Bioenergy Plan (2012-2019)
Since 2012, the long-term national plan of bioenergy embedded biodiesel. The 12th Five-Year Plan for Bioenergy Development, issued in 2012, was the first national plan targeting the development of bioenergy, and biodiesel was officially recognized as a strategic industry of bioenergy. It was synthetically supported with bioethanol and biogas to serve the national purposes of technology innovation of bioenergy, energy supply, and environmental sustainability. The National Energy Administration under the National Development and Reform Commission was the main institution to implement the plan, and it supported the production of first-generation biodiesel based on used cooking oil and non-edible energy crops and the innovation and commercialization of second-generation algal biodiesel. Later on, the 13th Five-Year Plan for Bioenergy Development issued in 2016, reconfirmed the inclusion of biodiesel in long-term national bioenergy development. The government would encourage the expansion of first-generation biodiesel based on non-edible energy crops, especially woody energy plants such as Jatropha curcas, and concurrently, the process innovation and mass production of algal biodiesel at low costs. The main policy objectives for the development of biodiesel at the time were energy supply continuity (13.24%), technology innovation (11.42%), and environmental sustainability (7.31%). Technology innovation fostered the innovation system of biodiesel, especially the innovation of algal biodiesel, and energy supply continuity emphasized the supply of biodiesel to aviation fuel. For example, in 2016, the Notice on Printing and Distributing the 13th Five-Year Plan for Renewable Energy Development announced the increase in biodiesel usage in transportation, especially aviation. Additionally, the notice revealed that the annual production of biodiesel should achieve 2 million tonnes by 2020.
The priority of policy instruments changed during this period. As the involvement of private companies steadily increased, supervised evaluation (12.79%) emerged as the most frequently used policy instrument regulating the licenses of market entry. Only private companies fulfilling the standards for production and the quality of products were licensed. However, these licenses were evaluated regularly, and the companies that could not maintain the standards could no longer manufacture and sell biodiesel products. Standard control (10.96%) was adopted to both manage the processes of production and the quality of biodiesel products. While private companies needed to follow the technical norms to produce BD 100 biodiesel, since 2019, only B5 biodiesel complying with the mandatory national standard could be sold in the market. Moreover, financial support (8.22%) remains the critical policy instrument to fund universities and research institutes for research of new species of microalgae and non-edible energy crops and allocate subsidies and tax exemptions to private companies participating in the standard production of biodiesel. Sample engineering (7.31%) was used to construct representative factories for the production of second-generation biodiesel based on algae. In conclusion, as the production of and market for first-generation biodiesel were gradually established, policy instruments were synthetically applied to optimize the supply of biodiesel. Supervised evaluation and standard control were used to banish the unqualified products, and financial support and sample engineering fostered the system of biodiesel innovation to move forward to the innovation and production of second-generation biodiesel from algae.

Evolution of Policy Networks
The dynamics of the policy networks that implemented biodiesel policies in China evolved with the transitions of policy contents. Figure 4 shows that throughout the three periods, the State Council, which guided the policymaking processes, was the important node, and the National People's Council, which legitimized legal foundations, was essential in the first and second periods. Table 6 displays institutions and text composition of policies on the development of biodiesel. As shown in Table 6 nine policies each). The coordination between ministries was relatively frequent. The National Development and Reform Commission twice jointly issued policies with the Ministry of Science and Technology and once with the Ministry of Finance.
By revising the Renewable Energy Law in the second period, the National People's Council continuously provided the legal foundation, and the State Council continued as the main institution for the implementation of biodiesel policies. However, the roles of inferior ministries under the State Council switched. The National Development and Reform Commission, Ministry of Science and Technology, and Ministry of Finance shared equal responsibilities in the network as the main responders for the promotion of biodiesel policies. Each of the three ministries issued 3 of 16 policies. In practice, compared with the first period, the Ministry of Science and Technology and Ministry of Finance played more active roles, while the National Development and Reform Commission took less responsibility in the implementation of biodiesel policies. Furthermore, the Ministry of Ecology and Environment and Ministry of Commerce were no longer involved in the policy network of biodiesel policies. While the National Development and Reform Commission and Ministry of Science and Technology still jointly issued policies, the Commission did not issue policies with the Ministry of Finance in the second period.
The State Council continued as the main institution to implement biodiesel policies in the third period, and the National People's Council, which no longer provided a legal foundation for the development of      implemented other biodiesel policies afterward. The National Development and Reform Commission accepted the main responsibility of promoting biodiesel (six of nine policies). Furthermore, the Ministry of Finance and Ministry of Science and Technology also contributed to launching biodiesel policies (two of nine policies each). The coordination between ministries was relatively frequent. The National Development and Reform Commission twice jointly issued policies with the Ministry of Science and Technology and once with the Ministry of Finance.
By revising the Renewable Energy Law in the second period, the National People's Council continuously provided the legal foundation, and the State Council continued as the main institution for the implementation of biodiesel policies. However, the roles of inferior ministries under the State Council switched. The National Development and Reform Commission, Ministry of Science and Technology, and Ministry of Finance shared equal responsibilities in the network as the main responders for the promotion of biodiesel policies. Each of the three ministries issued 3 of 16 policies. In practice, compared with the first period, the Ministry of Science and Technology and Ministry of Finance played more active roles, while the National Development and Reform Commission took less responsibility in the implementation of biodiesel policies. Furthermore, the Ministry of Ecology and Environment and Ministry of Commerce were no longer involved in the policy network of biodiesel policies. While the National Development and Reform Commission and Ministry of Science and Technology still jointly issued policies, the Commission did not issue policies with the Ministry of Finance in the second period.
The State Council continued as the main institution to implement biodiesel policies in the third period, and the National People's Council, which no longer provided a legal foundation for the development of biodiesel, faded from the policy network. Under the State Council, the roles of inferior ministries changed again. The National Development and Reform Commission became the most essential ministry to launch biodiesel policies. The National Energy Administration under the Commission emerged within the network as the critical institution subordinate to the ministry. The Commission itself issued six policies, and the National Energy Administration also launched six policies. While the National Development and Reform Commission in sum promoted 12 of 19 policies, weighting approximately 63% of the overall policies in the period, the Ministry of Science and Technology and Ministry of Finance only implemented one policy each and played minor roles in the biodiesel policy network. Thus, the implementation of biodiesel policies was concentrated in the National Development and Reform Commission, and the coordination between ministries at the same time reduced. The National Development and Reform Commission did not jointly issue any policy with other ministries in the period but allocated the responsibilities of policy implementation to the National Energy Administration.

Discussion and Conclusions
This article analyzed the transitions of biodiesel policies in China using the content analysis method. In Section 1, we set up two research questions and portrayed the policy transitions and policy networks in Sections 3 and 4. Considering the research questions proposed at the beginning of this article, in this section, we further explored the two research questions based on our empirical results and concluded the article with our empirical contributions and suggestions for future research.
The first research question is the following: How did biodiesel policies transit in China regarding policy objectives and policy instruments? The policy objectives of China's biodiesel policies evolved. Energy supply continuity was the most important policy objective throughout the three periods and was steadily followed by technology innovation and environmental sustainability. Only in the second period did industrial development emerge as one of the most essential policy objectives. Next, the policy objectives shifted with the innovation of technologies. In the first period, as first-generation biodiesel initially emerged, the policies emphasized the increase in the supply of biodiesel. While the production of first-generation biodiesel constantly increased, the policy objectives strengthened the development of the industry and enlarged the market demand to build the system of innovation of biodiesel. Until the third period, with the emergence of second-generation algal biodiesel, policy objectives again focused on biodiesel supply. Nevertheless, the supply of biodiesel in the third period focused on second-generation rather than first-generation biodiesel. Besides, rural development continued as the supplementary policy objective over the three periods. Contrary to Horst's [25] analysis that rural development is one of the main objectives of biomass energy policies in the United Kingdom, in the experiences of China, rural development received minor priority compared with energy supply continuity and other policy objectives. Moreover, policy instruments changed with the transitions of policy objectives. When the supply of first-generation biodiesel was the main policy purpose in the first period, financial support, standard control, and sample engineering were used to accelerate the production of biodiesel. Once industrial development became one of the critical policy concerns in the second period, market configuration became the essential policy instrument. As policy objectives focused on the supply of second-generation biodiesel in the third period, financial support, standard control, and sample engineering were used again as the critical policy instruments, along with supervised evaluation, to manage the market entry of first-generation biodiesel to upgrade the quality of biodiesel products in the market.
The second research question is the following: How did policy networks of biodiesel evolve through the transitions of policies? The dynamics of policy networks in China changed with the evolution of policy contents. The National People's Council provided the legal foundations to guide the principal direction for the development of biodiesel, and the State Council continuously significantly influenced the promotion of biodiesel development. Nevertheless, the participation of different ministries under the State Council switched over time. Next, the Ministry of Ecology and Environment and Ministry of Commerce only issued the first biodiesel policy but were no longer involved in policy networks in the later periods. Contrastingly, the National Development and Reform Commission extensively burdened the responsibilities for the implementation of biodiesel policies throughout the three periods. Only in the second period, when market configuration was used as the main policy instrument to fulfill the objective of industrial development, the Commission equally shared responsibilities with the Ministry of Science and Technology and Ministry of Finance. The supply of biodiesel was a significant policy purpose in the first and third periods, and the National Development and Reform Commission continued as the dominant ministry to implement biodiesel policies. Additionally, because the implementation of biodiesel policies was concentrated within the Commission, the burden of the Commission even increased in the third period. The National Energy Administration under the Commission immediately emerged in the network as the main subordinate institution to launch biodiesel policies. Furthermore, the Ministry of Science and Technology and Ministry of Finance, which were once important nodes within the policy networks in the first and second periods, gradually faded in the third period. As long as biodiesel was embedded within the long-term national bioenergy plan, allocating the National Energy Administration to set up overall synthetic policies to support the development of biodiesel, the two ministries reduced coordination with the Commission, and they gradually stepped away from the policy network.
This article is one of the first attempts to analyze the evolution of biodiesel policies in China systematically. We adopted the research method of content analysis to explore the transitions of policy contents and the dynamics of policy networks. Lastly, future research could use more synthetic qualitative or quantitative research methods to improve the analysis of the effectiveness of biodiesel policies, resolve the limitations of the content analysis method, and further explore the underlying contexts driving the policy change of biodiesel in China.