An overview of biomass energy research with bibliometric indicators

Abstract

Biomass energy has the characteristics of renewable and decentralized and plays a certain role in mitigating climate change. Now it is considered to be a very important renewable energy and has great potential for development. Based on Science Citation Index Expanded and Social Sciences Citation Index databases, this paper retrieved the publication data through topic search using the keywords biomass energy and related words during 2007–2016. This paper investigates the development characteristics in biomass energy research based on bibliometrics methods and data mining techniques. The main purpose of this paper is to explore the knowledge structure and citation landscape in this field. The general development trends, Essential Science Indicators publications characteristics, and leading journals in this area are discussed. The main advantage of this analysis is based on massive data which can, to some extent, reveal the macrostate of the development of the field.

Keywords

Biomass energy bibliometrics data mining renewable energy international collaboration

Introduction

The energy crisis and environmental pollution are the two main factors that impede the sustainable developmentof the economy and society.^2,3 Excessive energy consumption makes the scarcity of energy resources more and more prominent.^1,4,5 While trying to improve the efficiency of existing energy use, countries around the world are actively seeking new ways of using energy.^6,7 Fortunately, renewable energy provides an opportunity to address these two worldwide difficult problems.^8,9 Biomass energy is one of the important sources of renewable energy^10,11 and it is the only renewable energy that can be used for power generation, heating, and fuel simultaneously.^12,13 In order to realize the transformation from traditional fossil energy economy to bio-energy economy and promote the sustainable use of biomass raw materials and energy utilization, many countries have not only enacted measures to promote the development of biomass energy, but have also developed specific development goals and planning.¹⁴ The development and utilization of biomass energy has attracted wide attention from governments and scientists.^15–17

At present, biomass energy is a hot research topic and well-established scientific research direction. There are thousands of scholars and scientists who undertake research in this area. The scientific publications about biomass energy are already more than 200,000, according to Web of Sciences (WoS). What’s more, the increasing trend is accelerating. In these circumstances, in order to fully understand the current situation and development trend of biomass energy research, it is of great significance to summarize the development course and existing problems of biomass energy and to indicate the direction of follow-up research based on comprehensive literature review.

Voloshin et al.¹⁸ made a deep analysis of the biofuel production from plant and algal biomass. Jambo et al.¹⁹ highlighted the prospects for development of the third-generation bioethanol feedstock. Doshi et al.²⁰ presented the economic efficiency and cost of the conventional biofuels, and pointed out the necessity and urgency of the development of a third-generation feedstock based on algae. Dong et al.²¹ made a comprehensive review on lipid recovery of the biofuel production. Biodiesel is renewable, nontoxic, and biodegradable, and it has important economic value and broad application market. Saluja et al.²² discussed the types and causes of instability and explored the current situation and development trend in this area. Based on the scientific publications on biofuels between 1998 and 2007, Gomes and Dewes²³ investigated the development history and orientation of the field of biofuels. Yu et al.²⁴ made scientometric review on low carbon energy technology investment based on bibliometric analysis methods.^25–31 The historical development process; auctorial collaboration degree; and the distributions of geography, journals, and subjects in this field are well investigated. In addition, the influential authors and institutions, as well as highly cited articles are explored in this study. Based on the bibliometric analysis methods,^{32–35,36,37} Mao et al.³⁸ investigated the field of biomass energy. A total of 33,072 biomass energy-related publications were investigated on various aspects, such as authorship, countries and institutions distributions, influential papers, and keywords.

Obviously, more and more studies have recognized the necessity of tracing the trajectory of biomass-related researches. However, up to now, some key issues have not yet been effectively addressed, such as the status quo of research on the development of biomass-related research, the distribution pattern of scientific research subjects in the field of biomass energy research, and what are the main journals of biomass energy research, and so on, all of which are worthy of academic attention. This paper analyzes the hot issues from the perspective of research papers and provides a reference for relevant research and decision-making in this field, and also provides useful clues for the tracking and retrospective of biomass-related research.

The paper is organized as follows. The next section describes the data and methods used in this paper. The subsequent section presents the empirical results. The final section summarizes the main results and conclusions of this study.

Data and methods

ISI WoS is the Web version of the three citation databases built by Thomson ISI and consists of three separate databases: Science Citation Index Expanded (SCIE), Social Sciences Citation Index (SSCI), and Arts & Humanities Citation Index.^39,40 It covers more than 8500 academic journals in the fields of natural sciences, engineering, social sciences, arts, and humanities.⁴¹ The data used in this paper are derived from ISI WoS, mainly because it has been widely used by scholars in the field of bibliometrics.^42,43

Since the consensus on the concept and definition of biomass energy has not yet been reached, existing papers tend to collect the literature data that contain the expression “biomass”³⁸ in the titles, abstract, or keywords. Based on the comprehensive analysis of the advantages and disadvantages of existing data collection methods and the purpose of this study, this paper constructed the following bibliographic records search strategy.

Topic search= (biomass OR biofuel OR biodiesel OR bioethanol OR biomass power OR biogas)

Timespan= (2007–2016)

Document type= (Article or Review)

Databases= (SCIE or SSCI)

Topic search means searches for topic terms in the following fields within a record: 1) Title, 2) Abstract, 3) Author Keywords, and 4) Keywords Plus®.⁴⁴

Based on the above search strategy, a total of 172,029 records were obtained. These publications appeared in 23 languages, covering hundreds of countries and regions. According to the number of publications, the top 3 countries are the USA (38,781), China (27,945), and Germany (10,461). This also demonstrates the dominant position and influence of these countries in the field of biomass energy research.

Essential Science Indicators (ESI) is a depth analysis tool based on the WoS core collection database. Based on ESI, the influential countries, institutions, and publications, as well as research frontiers in a field of research can be identified.^45,46 It has been widely used by policymakers; managers; intelligence analysts; and information specialists in government agencies, universities, businesses, laboratories, and publishing companies.^47,48 In this paper, we collected the ESI publications in the field of biomass energy for investigating the emerging trends. A total of 3185 biomass energy publications were retrieved on 12 April 2017. The annual biomass energy publication counts and quantitative distribution of ESI papers over the last decades are shown in Figure 1.

Figure 1.

Annual biomass energy publication counts and quantitative distribution of ESI papers.

The main purpose of this paper is to explore the knowledge structures and citation landscape in the field of biomass energy from 2007 to 2016. Among the many literature data visualization software, VOSviewer is a very effective tool that can display the complex relationship of the publications in that specific domain.^49–51 In this study, cooperative network among countries were presented based on VOSviewer. Furthermore, customized data mining methods are presented to discover the pattern and characteristics of international cooperation. Additionally, H-index and impact factor (IF) are also applied to study the intellectual structure of biomass energy. The definition of the index is that a scholar with an index of h has published h papers each of which has been cited in other papers at least h times.^52,53

Empirical results

General analysis

As we all know, the number of published papers can reflect the size of the research scale to a certain extent. According to Figure 1, from 2007 to 2016, the scale of biomass energy research has maintained a rapid growth rate which revealed the characteristics of biomass energy research flourishing around the world. Figure 2 shows the geographical distribution of the top 20 productive countries in this area.

Figure 2.

Geographical distribution of the top 20 productive countries. TP: total number of papers.

The leading edge of USA is very prominent in the field of biomass energy research. In 2007, the USA published a total of 2273 papers in this field, three times of China (745), the second productive country in the world. As shown in Table 1, the USA produced more than 20% papers in the field of biomass energy during the past 10 years (2007–2016). But this lead is slowly declining. In 2016, China’s paper production was 5902, surpassing the number of papers of USA in the field. Over the past 10 years, China has made significant progress in the field of biomass energy research. China’s number of papers increased seven times during this period, from 745 in 2007 to 5902 in 2016. From a global perspective, China has the largest increase in the world share. China’s share of the world in the field of biomass energy rose from 11.45% in 2007–2011 to 18.94% in 2012–2016 (see Table 1). Table 1 also included other detailed information about the top 20 most productive countries in this field during the past 10 years (2007–2016). Note: TP_07–11 means the total publications during 2007–2011; TP_12–16 means the total publications during 2012–2016.

Table 1.

Publications of the top 20 countries between 2007 and 2016.

Countries/Regions	2007	2008	2009	2010	2011	2012	2013	2014	2015	2016	TP_07–16	2007–2011			2012–2016			Share change	Rank change
Countries/Regions	2007	2008	2009	2010	2011	2012	2013	2014	2015	2016	TP_07–16	TP_07–11	TP_07–11%	Rank	TP_12–16	TP_12–16%	Rank	Share change	Rank change
Total	8900	10,726	12,138	13,823	16,319	18,096	20,414	22,085	23,809	25,719	172,029	61,906	100.00		110,123	100.00
USA	2273	2607	2868	3338	3929	4241	4560	4786	4985	5194	38,781	15,015	24.25	1	23,766	21.58	1	−2.67	0
China	745	1053	1351	1759	2179	2606	3391	4124	4835	5902	27,945	7087	11.45	2	20,858	18.94	2	7.49	0
Germany	628	625	750	843	968	1059	1227	1335	1451	1575	10,461	3814	6.16	4	6647	6.04	4	−0.12	0
India	467	600	675	782	948	1079	1195	1360	1509	1787	10,402	3472	5.61	5	6930	6.29	3	0.68	−2
UK	654	700	746	836	949	1056	1132	1167	1298	1433	9971	3885	6.28	3	6086	5.53	6	−0.75	3
Brazil	391	548	636	703	928	999	1178	1301	1352	1510	9546	3206	5.18	6	6340	5.76	5	0.58	−1
Spain	453	551	624	718	823	974	1021	1128	1182	1259	8733	3169	5.12	8	5564	5.05	7	−0.07	−1
Canada	484	602	579	684	849	883	980	1029	1106	1103	8299	3198	5.17	7	5101	4.63	8	−0.53	1
France	401	528	523	609	702	756	885	910	1048	1052	7414	2763	4.46	9	4651	4.22	9	−0.24	0
Australia	379	410	414	520	608	722	801	879	1037	1093	6863	2331	3.77	11	4532	4.12	10	0.35	−1
Japan	394	519	521	583	625	644	823	792	819	911	6631	2642	4.27	10	3989	3.62	12	−0.65	2
Italy	317	345	474	455	498	650	707	814	983	1027	6270	2089	3.37	12	4181	3.80	11	0.42	−1
Netherlands	302	303	370	388	383	487	540	537	586	638	4534	1746	2.82	13	2788	2.53	14	−0.29	1
South Korea	135	205	228	290	376	489	629	627	733	760	4472	1234	1.99	16	3238	2.94	13	0.95	−3
Sweden	301	284	277	309	392	455	523	589	585	626	4341	1563	2.52	14	2778	2.52	15	0.00	1
Poland	114	163	202	261	281	303	382	442	467	578	3193	1021	1.65	18	2172	1.97	17	0.32	−1
Turkey	188	266	343	293	343	337	299	307	351	400	3127	1433	2.31	15	1694	1.54	20	−0.78	5
Malaysia	36	60	112	180	297	300	398	502	529	572	2986	685	1.11	20	2301	2.09	16	0.98	−4
Denmark	159	185	199	221	267	317	327	373	406	445	2899	1031	1.67	17	1868	1.70	18	0.03	1
Finland	144	155	169	174	248	313	329	385	394	363	2674	890	1.44	19	1784	1.62	19	0.18	0

TP: total number of papers; TP_07–11: the total publications during 2007–2011; TP_12–16: the total publications during 2012–2016.

Studies have shown that the total number of citations of a country can reflect the overall picture of the country’s academic influence. The citation of USA is far more than other countries in the field of biomass energy. The USA accounted for 27.62% of all citations during 2007–2011 and 23.50% during 2012–2016. In addition to the USA, China, UK, and Germany are more influential than other countries in the field of biomass energy; they received 357,439, 231,625, and 20,078 citations, respectively. China’s academic influence is expanding in the field of biomass energy, and the citation share of China is only 9.94% in 2007–2011 and 14.34% in 2012–2016 (see Table 2).

Table 2.

Citations distribution of the top 15 countries between 2007 and 2016.

Countries/Regions	TC_07–16	TC_07–16/TP_07–16	2007–2011				2012–2016				Share change%	Rank change
Countries/Regions	TC_07–16	TC_07–16/TP_07–16	TC_07–11	TC_07–11/TP_07–11	TC_07–11%	Rank	TC_12–16	TC_12–16/TP_12–16	TC_12–16%	R	Share change%	Rank change
Total	3,093,027	17.98	2,040,183	32.96			1,071,577	9.73
USA	810,517	20.90	563,488	37.53	27.62	1	251,851	10.60	23.50	1	−4.12	0
China	357,439	12.79	202,834	28.62	9.94	2	153,696	7.37	14.34	2	4.40	0
UK	231,625	23.23	159,383	41.79	7.81	3	74,452	12.23	6.95	3	−0.86	0
Germany	200,786	19.19	133,120	38.34	6.52	4	68,345	10.28	6.38	4	−0.15	0
Spain	151,718	17.37	99,785	25.68	4.89	5	52,892	9.51	4.94	5	0.04	0
Canada	141,195	17.01	97,333	30.36	4.77	6	45,063	8.83	4.21	9	−0.57	3
India	138,015	13.27	90,366	28.52	4.43	8	48,202	6.96	4.50	6	0.07	−2
France	136,180	18.37	90,510	28.30	4.44	7	46,763	10.05	4.36	7	−0.07	0
Australia	121,435	17.69	76,348	27.63	3.74	9	46,222	10.20	4.31	8	0.57	−1
Netherlands	106,703	23.53	71,012	30.46	3.48	10	36,668	13.15	3.42	11	−0.06	1
Italy	101,740	16.23	64,839	24.54	3.18	12	37,821	9.05	3.53	10	0.35	−2
Japan	100,064	15.09	68,356	32.72	3.35	11	32,565	8.16	3.04	13	−0.31	2
Brazil	93,757	9.82	60,623	34.72	2.97	13	33,514	5.29	3.13	12	0.16	−1
Sweden	81,008	18.66	52,631	42.65	2.58	14	29,066	10.46	2.71	14	0.13	0
Denmark	59,916	20.67	39,655	38.46	1.94	15	20,872	11.17	1.95	15	4.09E-05	0

TC: total citations; TP: total number of papers.

Since the TC index is greatly influenced by the total number of papers (TP), the average number of citations per paper (TC/TP) describes the average impact of each paper. Therefore, the index of TC/TP can better reflect the average influence of each paper. As shown in Table 2, the average citation of each paper is 17.98. Regarding the index of TC/TP, the Netherlands ranks first with the value of 23.53 and it was followed by UK (23.23), USA (20.90), and Denmark (20.67).

In particular, although the TC and TP of China are all ranked second, the value of TC/TP is only 12.79, not only far below the USA, UK, Germany, and other countries, but also lower than the average of the research area (17.98). Further analysis revealed that, during 2007–2011, China received only 9.94% of the citations in the world share based on the 11.45% of its papers. During 2012–2016, China received only 14.34% of the citations in the world share based on 18.94% of its papers. The above analysis shows that the progress of academic influence in China is remarkable, but compared with the development of the number of papers, the development of academic influence is relatively lagging behind. Figure 3 shows the average citations of the top 15 countries (based on TC) in the field of biomass energy from 2007 to 2011, 2012 to 2016, respectively.

Figure 3.

Average citations of the top 15 countries.

ESI publications

With the development of communication technology and network, the number of scientific research achievements has increased at a rapid pace. However, there are only a few important achievements which can greatly promote the development of the subject. In addition, most of the important results can be obtained with higher citation frequency. Therefore, the ESI papers are widely used in the evaluation of scientific research. Table 3 shows the detailed information of the ESI papers in the field of biomass energy (data analysis time was 12 April 2017). There are 3185 highly cited papers, accounting for 1.85% of the TPs (172,029).

Table 3.

ESI publications of the top 20 countries between 2007 and 2016.

Countries/Regions	2007	2008	2009	2010	2011	2012	2013	2014	2015	2016	TP	ESI output ratio	2007–2011			2012–2016			Share change%	Change%
Countries/Regions	2007	2008	2009	2010	2011	2012	2013	2014	2015	2016	TP	ESI output ratio	TP_07–11	TP_07–11%	ESI output ratio_07–11	TP2	TP2%	ESI output ratio_07–11	Share change%	Change%
Total	206	277	293	321	357	349	330	338	333	366	3185	1.85	1454		2.35	1716		1.56	8.26	−0.79
USA	83	94	111	129	160	145	127	139	110	106	1204	3.10	577	39.68	3.84	627	36.54	2.64	−3.15	−1.20
China	25	38	30	35	35	43	49	63	77	77	472	1.69	163	11.21	2.30	309	18.01	1.48	6.80	−0.82
UK	15	34	28	44	48	44	46	43	46	38	386	3.87	169	11.62	4.35	217	12.65	3.57	1.02	−0.78
Germany	19	30	21	32	33	38	34	33	29	37	306	2.93	135	9.28	3.54	171	9.97	2.57	0.68	−0.97
France	8	11	18	25	22	20	31	32	37	26	230	3.21	84	4.81	3.00	146	8.74	3.31	3.93	0.31
Australia	3	10	14	19	24	37	27	27	27	32	220	2.78	70	5.78	3.04	150	8.51	3.14	2.73	0.10
India	11	22	33	21	17	26	11	24	25	23	213	2.05	104	7.15	3.00	109	6.35	1.57	−0.80	−1.42
Canada	17	15	12	26	16	23	21	26	28	18	202	2.43	86	5.91	2.69	116	6.76	2.27	0.85	−0.42
Spain	18	14	10	13	26	29	22	24	19	23	198	2.27	81	5.57	2.56	117	6.82	2.10	1.25	−0.45
Netherlands	15	12	18	11	12	28	21	16	23	17	173	3.82	68	4.68	3.89	105	6.12	3.77	1.44	−0.13
Italy	7	7	18	11	11	21	15	22	21	15	148	2.36	54	3.71	2.58	94	5.48	2.25	1.76	−0.34
Sweden	12	8	5	9	10	16	20	13	11	13	117	2.70	44	3.03	2.82	73	4.25	2.63	1.23	−0.19
Malaysia	1	3	8	7	16	13	18	17	13	16	112	3.75	35	2.41	5.11	77	4.49	3.35	2.08	−1.76
Switzerland	7	10	9	7	8	16	14	11	12	11	105	4.60	41	2.82	4.79	64	3.73	4.48	0.91	−0.30
Denmark	5	8	9	5	13	21	12	9	8	14	104	3.59	40	2.75	3.88	64	3.73	3.43	0.98	−0.45
Japan	7	9	7	6	10	12	16	10	8	16	101	1.52	39	2.68	1.48	62	3.61	1.55	0.93	0.08
Turkey	4	18	22	10	19	2	2	6	6	3	92	2.94	73	5.02	5.09	19	1.11	1.12	−3.91	−3.97
Belgium	5	8	6	8	6	14	16	6	12	8	89	3.77	33	2.27	3.85	56	3.26	3.73	0.99	−0.12
Brazil	8	3	8	8	2	13	7	12	11	13	85	0.89	29	1.99	0.90	56	3.26	0.88	1.27	−0.02
Austria	5	7	8	4	10	4	12	12	12	9	83	4.47	34	2.34	5.13	49	2.86	4.10	0.52	−1.03

ESI: Essential Science Indicators; TP: total number of papers

The TPs of USA in the field of biomass energy are 38,781 (see Table 1), of which there are 1204 papers included in ESI database. The ESI papers’ output rate of USA is 3.10% which is more than the world average of 1.85%. On the output rate of ESI publications, Switzerland had the best performance with the ratio of 4.60% and it was followed by UK (3.87%), Netherlands (3.82%), and Belgium (3.77%).

China’s ESI highly cited papers have increased by leaps from 2007 to 2016, from 25 in 2007 to 77 in 2016, indicating that China has made significant progress in this area. However, compared with the world level, China still has a lot of room for improvement. For example, between 2007 and 2016, there were 472 ESI papers in China, accounting for 1.69% of the total amount of biomass energy papers in the same period. This ESI paper output ratio is not only much lower than that of the USA (3.10%), United Kingdom (3.87%), and Germany (2.93%), but also lower than the world average rage (1.85%) and some developing countries such as India (2.05%), Malaysia (3.75%), and Turkey (2.94%). Previous research results show that the amount of ESI publications of China in the field of biomass energy has made great progress, but there is still a big gap with other countries. Figure 4 shows the output rate of ESI publications of the top 20 countries (based on total ESI publication numbers) in the field of biomass energy from 2007 to 2011, 2012 to 2016, respectively.

Figure 4.

Output rate of ESI publications of the top 20 countries.

Leading journals analysis

The IF is one of the most important indexes for determining the importance of journals. However, it varies widely in different disciplines. Since biomass energy is an interdisciplinary field of research, it is difficult to accurately judge the importance of journals by relying solely on IF. In this paper, five indexes such as TP, IF, five-year IF, ESI publication number, and TC/TP were used to rank the journals in the field of biomass energy. For each indicator, the journals are sorted separately. Ranked first, giving 1; second, 0.95; third, 0.9; and so forth, 20th in line 0.05. In addition, assume that the weights of the five indexes are the same, the final journal ranking results are shown in Table 4. The top 10 journals in biomass energy are Renewable Sustainable Energy Reviews, Bioresource Technology, Applied Energy, Soil Biology Biochemistry, Atmospheric Chemistry and Physics, Fuel, Environmental Science Technology, Chemical Engineering Journal, Energy, and Biomass Bioenergy. Tables 5 and 6 show the countries in the top 10 journals.

Table 4.

Journal ranking.

Journals	Total scores	TP		IF		5-IF		ESI		TC/TP
Journals	Total scores	TP	Rank	IF	Rank	5-IF	Rank	ESI	Rank	TC/TP	Rank
Renewable Sustainable Energy Reviews	4.71	1476	7	6.798	2	7.896	2	255	1	33.5	3
Bioresource Technology	4.34	6907	1	4.917	9	5.744	7	125	3	25.51	8
Applied Energy	4.23	1304	8	5.746	5	6.222	6	117	4	24.4	9
Soil Biology Biochemistry	3.89	1299	9	4.152	13	5.041	11	85	5	26.53	6
Atmospheric Chemistry and Physics	3.77	978	20	5.114	8	5.626	9	63	7	33.15	4
Fuel	3.71	2651	3	3.611	17	4.14	16	143	2	21.04	12
Environmental Science Technology	3.71	985	19	5.393	6	6.396	5	35	15	32.4	5
Chemical Engineering Journal	3.51	1011	18	5.31	7	5.439	10	59	9	21.04	13
Energy	3.4	1184	10	4.292	12	4.81	12	53	11	19.08	16
Biomass Bioenergy	2.91	2679	2	3.249	23	4.146	15	17	19	18.05	19
Fuel Processing Technology	2.74	1163	11	3.847	15	3.949	18	9	23	19.03	17
International Journal of Hydrogen Energy	2.71	1477	6	3.205	24	3.419	26	37	14	19.39	15
Energy Fuels	2.60	2344	4	2.835	27	3.34	27	55	10	17.44	21
Renewable Energy	2.60	1033	17	3.404	20	4.068	17	45	13	17.33	22
Applied Microbiology and Biotechnology	2.46	1048	16	3.376	21	3.882	20	8	26	21.42	11
Plant and Soil	2.23	1145	12	2.969	26	3.581	22	20	17	15.42	25
PLOS One	2.17	2113	5	3.057	25	3.535	24	15	20	10.68	30
Forest Ecology and Management	1.83	1130	13	2.826	28	3.23	28	11	21	15.26	26
Research Advances	1.66	1084	14	3.289	22	3.485	25	3	28	6.27	33
Industrial Engineering Chemistry Research	1.57	1051	15	2.567	30	2.718	31	2	29	18.02	20

ESI: Essential Science Indicators; 5-IF: five-year IF; IF: impact factor; TC: total citations; TP: total number of papers.

Table 5.

Leading countries in Journal 1–5.

Countries/Regions	Renewable Sustainable Energy Reviews			Bioresource Technology			Applied Energy			Soil Biology Biochemistry			Atmospheric Chemistry and Physics
Countries/Regions	TP	TC	TC/TP	TP	TC	TC/TP	TP	TC	TC/TP	TP	TC	TC/TP	TP	TC	TC/TP
USA	103	3727	36.18	1155	34,841	30.17	203	4586	22.59	333	9763	29.32	561	22,658	40.39
China	183	4518	24.69	1899	38,338	20.19	263	6820	25.93	185	4167	22.52	138	5548	40.20
Germany	40	939	23.48	214	4176	19.51	54	684	12.67	249	7678	30.84	223	7474	33.52
India	229	10,162	44.38	532	14,869	27.95	62	2147	34.63	0	0	0.00	25	620	24.80
UK	80	2614	32.68	223	7481	33.55	77	1396	18.13	159	5194	32.67	192	7017	36.55
Brazil	79	1313	16.62	225	4912	21.83	25	506	20.24	0	0	0.00	54	1241	22.98
Spain	71	2099	29.56	414	11,918	28.79	76	1293	17.01	81	2219	27.40	37	1233	33.32
Canada	55	2530	46.00	267	7271	27.23	55	1101	20.02	73	1865	25.55	91	2139	23.51
France	24	439	18.29	194	5059	26.08	24	504	21.00	100	2014	20.14	175	5877	33.58
Australia	54	1465	27.13	160	3478	21.74	33	782	23.70	117	2761	23.60	39	932	23.90
Japan	19	920	48.42	299	7031	23.52	62	1248	20.13	19	406	21.37	69	3865	56.01
Italy	49	1145	23.37	189	3948	20.89	91	2066	22.70	49	1261	25.73	69	2838	41.13
Netherlands	51	1708	33.49	112	4379	39.10	38	744	19.58	46	1089	23.67	68	3766	55.38
South Korea	20	429	21.45	437	10,402	23.80	44	773	17.57	0	0	0.00	20	1267	63.35
Sweden	28	466	16.64	24	3665	152.71	124	2380	19.19	75	2632	35.09	38	1020	26.84
Poland	28	518	18.50	56	1030	18.39	0	0	0.00	0	0	0.00	0	0	0.00
Turkey	52	1883	36.21	138	4637	33.60	21	2191	104.33	0	0	0.00	0	0	0.00
Malaysia	210	8811	41.96	45	1322	29.38	45	1322	29.38	0	0	0.00	0	0	0.00
Denmark	16	709	44.31	127	4037	31.79	41	1138	27.76	48	1040	21.67	15	322	21.47
Finland	29	822	28.34	82	1568	19.12	27	483	17.89	37	814	22.00	58	1728	29.79

TC: total citations; TP: total number of papers

Table 6.

Leading countries in Journal 6–10.

Countries/Regions	Fuel			Environmental Science Technology			Chemical Engineering Journal			Energy			Biomass Bioenergy
Countries/Regions	TP	TC	TC/TP	TP	TC	TC/TP	TP	TC	TC/TP	TP	TC	TC/TP	TP	TC	TC/TP
USA	356	7428	20.87	554	20,766	37.48	0	0	0.00	97	1712	17.65	614	11,256	18.33
China	176	2483	14.11	165	4805	29.12	231	3762	16.29	176	2483	14.11	198	3528	17.82
Germany	92	1349	14.66	65	1495	23.00	0	0	0.00	36	543	15.08	164	2096	12.78
India	183	5127	28.02	25	680	27.20	66	2304	34.91	86	1743	20.27	153	3340	21.83
UK	182	4605	25.30	68	1551	22.81	32	806	25.19	57	979	17.18	183	4138	22.61
Brazil	215	2686	12.49	0	0	0.00	41	640	15.61	59	906	15.36	106	1582	14.92
Spain	213	4423	20.77	34	955	28.09	154	3203	20.80	72	1060	14.72	134	2133	15.92
Canada	138	2067	14.98	55	1424	25.89	35	781	22.31	47	721	15.34	138	2067	14.98
France	83	1529	18.42	32	995	31.09	49	902	18.41	0	0	0.00	81	1461	18.04
Australia	0	0	0.00	55	1654	30.07	23	563	24.48	0	0	0.00	44	618	14.05
Japan	115	3384	29.43	20	499	24.95	35	457	13.06	21	309	14.71	60	763	12.72
Italy	91	1197	13.15	25	700	28.00	61	1238	20.30	72	1488	20.67	203	3629	17.88
Netherlands	33	1512	45.82	31	773	24.94	21	318	15.14	20	871	43.55	111	3448	31.06
South Korea	79	887	11.23	17	733	43.12	44	605	13.75	62	952	15.35	51	702	13.76
Sweden	0	0	0.00	29	641	22.10	16	180	11.25	55	883	16.05	145	3509	24.20
Poland	34	410	12.06	0	0	0.00	11	177	16.09	33	405	12.27	36	486	13.50
Turkey	84	2593	30.87	6	69	11.50	43	1796	41.77	30	654	21.80	36	1029	28.58
Malaysia	52	1188	22.85	0	0	0.00	38	801	21.08	60	1738	28.97	51	1343	26.33
Denmark	32	618	19.31	26	567	21.81	0	0	0.00	46	1993	43.33	91	1853	20.36
Finland	64	1244	19.44	12	140	11.67	23	338	14.70	15	300	20.00	105	1578	15.03

TC: total citations; TP: total number of papers.

Conclusion

Based on the large amounts of WoS data, this paper investigated the development characteristics of the biomass energy publication which appeared from 2007 to 2016 by means of bibliometrics and data mining. The leading edge of USA is very prominent in the field of biomass energy research. From a global perspective, China has the largest increase in the world share. The citation of USA is far more than other countries in the field of biomass energy. The progress of academic influence in China is remarkable, but compared with the development of the number of papers, the development of academic influence is relatively lagging behind. Switzerland had the best performance on ESI papers’ output rate and it was followed by UK, Netherlands, and Belgium. China’s ESI highly cited papers have increased significantly, indicating that China has made significant progress in this area. However, compared with the world level, China still has a lot of room for improvement. The top 3 journals in biomass energy are Renewable Sustainable Energy Reviews, Bioresource Technology, and Applied Energy.

There is no doubt that the analysis based on massive data can, to some extent, reveal the macrostate of the development of the field. Based on the analysis of this paper, it is possible to explore the inner structure of the biomass energy publication.

Footnotes

Declaration of conflicting interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: The work was supported by the project of philosophy and Social Science in Zhejiang under Grant 16NDJC159YB, the Zhejiang Science & Technology Plan of China under Grant 2015C33024, and the Zhejiang Provincial Natural Science Foundation of China under Grant LY17G010007.

Dejian Yu received PhD in Management Science and Engineering from Southeast University, China in 2012. He is currently an associated professor with the School of Government Audit, Nanjing Audit University, Nanjing, China. He has authored more than 40 scientific articles. His current research interests include fuzzy sets,information fusion, multi-criteria decision making and scientometrics.

Sun Meng received the master's degree in management Science and Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing, China in 2007. She is currently a lecturer in Yunnan University of Finance and Economics, Kunming. She has published more than 10 peer-reviewed papers in high-quality international journals. Her current research interest includes energy analysis and DEA model.

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