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LOGO Jiangsu University
A bibliometric analysis based review on wind
power price
2016-02-14
Mei Sun
Center for Energy Development and Environmental Protection, Jiangsu University
Authors: Cuixia Gao1, Mei Sun*,1, Yong Geng*,2, Rui Wu3,4
1 Center for Energy Development and Environmental Protection, Jiangsu University, Zhenjiang, China 2 School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai, China 3 Key Lab of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Shenyang, China 4 University of Chinese Academy of Sciences, Beijing, China
Outline
Background 1
Data and methods 2
Results and discussions 3
Looking forward 4
Conclusions 5
Background
Renewable power generation has been globally promoted.
With the increasing negative effects of fossil fuel combustion on the environment in addition to
limited stock of fossil fuel, many countries have paid more attention on supporting environmentally
friendly energy generation, particularly for solar power and wind power.
1
Among all the renewable energy
sources, wind power experienced
the fast increase.
The wind power capacity at the
end of 2014 was 369.6GW,
representing cumulative market
growth of more than 16%, which is
lower than the average growth rate
over the last 19 years (1996-2014) of
almost 25%.
Fig. 1. Global annual new added installed capacity of wind
generation (MW) during 1997-2014.
Background
By the end of 2014, Six countries had more than 10,000MW of installed capacity.
1
Background
However, the rapid development of wind power also faces a problem, namely
relatively higher price, which is now one of the main barriers affecting further
development of wind power industry. Consequently, how to establish a reasonable pricing
mechanism has become an urgent problem.
Wind power price (WPP) mechanisms can be mainly divided into three categories in the
world.
• Fixed price, implemented in Germany, Denmark, Portugal and Spain.
• Tender price, implemented in the United Kingdom, Canada, Ireland, and France. This
means that the lowest price will win through the project bidding according to the
government’s plan of wind power installation capacity.
• Renewable energy quota system, implemented in Japan. It is an indirect measure to
support wind power which requires remaining a certain percentage of renewable energy in
the total electricity mix.
1
Background
We try to provide a systemic and quantitative image about the evolution of
WPP related studies. All the relevant researchers can better understand the research
progresses and hotpots, so that they can identify the appropriate directions for their
future study.
1
Data and methods
Scopus provides a comprehensive and standardized exporting data and has been widely
used by academia.
The keywords “wind power price” and “wind electricity price” were used to search the
related publications published during the period of 1997 to 2014.
As a result, 2359 publications were obtained. Of all publications retrieved from Scopus,
peer-reviewed research articles account for 49.08%, followed by conference papers (38.88%),
review papers (4.3%), and others (e.g. book chapter, conference reviews, notes, short surveys,
business articles, articles in press, books, letters and reports). Similarly, English (92.65%) is the
most frequently used language for such a search, followed by Chinese (2.97%), German
(2.49%) and others.
In order to provide an international perspective, only research articles, conference papers
and review papers published in English are further analyzed. Finally, a total of 1994 documents
were found that related to WPP.
2
Data:
Data and methods
Network analysis serves as a lens on the
insights underlying a network of nodes and links
through which information or social relationships
travel.
Here, network analysis is conducted in order
to establish a network with the nodes that
represented articles, keywords, or countries. Such a
network can help evaluate the importance and
influence of a node by measuring the centrality of
the nodes.
Among various software tools, Gephi is used
frequently for the visualization of networks.
2
Methods:
Social network analysis——Gephi Bioliometric——Bibexcel
Bibexcel is another software tool to
perform bibliometric and network analysis.
Here, the complex network analysis is
undertaken to analyze the academic
collaboration among different countries and
articles using Bibexcel combining with
Gephi.
• Persson, O., R. Danell, and J. Wiborg Schneider. How to use Bibexcel for various types of bibliometric analysis. In
celebrating scholarly communication studies: A festschrift for Olle Person at his 60th birthday. Copenhagen: ISSI. 2009.
• Darvish H. The impact of the latent semantic analysis on science and technology: a bibliometric analysis. In: Proceedings of
the 12th world multi-conference on systems, cybernetics and informatics 2008; 5: 224-28.
3
3.1 Analysis of review publications
Results and discussions
Among 1994 publications, 91 papers are review papers, accounting for 4.3% of the total.
The majority of review papers were published in Renewable and Sustainable Energy Reviews
(with an amount of 36 papers), accounting for 40% of the total amount of such papers. The rest 51
papers were published in 45 kinds of different journals.
Most review papers focus on renewable energy price and policies. For example, Salo and Syri
reviewed the existing knowledge of offshore wind costs in Finland and obtained a reasonable tariff
price of 115 €/MWh which is higher than the current price level (83.5 €/MWh). Zhao et al. reviewed
the costs and benefits of renewable energy power subsidy in China; Ahmed reviewed the production
costs of electricity combined with wind power density to estimate the price of each kWh electricity
from the wind farms in Egypt.
However, no review papers provide a holistic and quantitative overview on WPP related
publications by means of bibliometric analysis and complex network analysis.
3
3.2 The performances of related publications
Results and discussions
Fig. 2. Numbers of NO, TC and ACPP during the period of 1997-2014.
Note: Countries in blue, green and red respectively correspond to the annual first, second and third largest published
countries.
• The articles published in the last 9 years accounted for 91% of the total published articles.
• The annual top 3 largest publication countries include the U.S., Denmark, United Kingdom, Germany,
Australia, Iran, Greece, Spain, Sweden, Norway, India, Italy, Iceland, Japan, Netherlands, Canada, and China.
• The NO experienced two substantial increases in 2006 and 2012 due to the meeting of G7 countries and a
wide adjustments of renewable energy policies, respectively.
NO: number of articles
TC: total citations of articles
ACPP: average citations per year per article
3
3.3 Journal’s performances
Results and discussions
Table 1 The top 20 journals or related conferences.
Journals/Conferences TP 2 % 3 IF 4
Energy Policy 144 7.25 2.575
Renewable and Sustainable Energy Reviews 65 3.27 5.901
Renewable Energy 60 3.02 3.476
IEEE Transactions on Power Systems 51 2.57 2.814
Energy 47 2.37 4.844
Applied Energy 35 1.76 5.613
IEEE Power and Energy Society General Meeting, PES 2012 1 24 1.21 -
Energy Economics 24 1.21 2.708
IEEE Transactions on Sustainable Energy 20 1.01 3.656
Power 20 1.01 0.048
IEEE Transactions on Smart Grid 18 0.91 4.252
European Wind Energy Conference and Exhibition, EWEC 2010 1 16 0.81 -
IEEE Power and Energy Society General Meeting, PES 2011 1 15 0.75 -
International Journal of Hydrogen Energy 15 0.75 3.313
IEEE Power and Energy Society General Meeting, PES 2010 1 15 0.75 -
Energy Conversion and Management 15 0.75 4.380
Wind Engineering 15 0.75 1.414
International Journal of Electrical Power and Energy Systems 12 0.60 3.432
IET Renewable Power Generation 12 0.60 1.904
Electric Power Systems Research 11 0.55 1.749 1 Conferences or Meetings organized for specific research issues. 2 The total publications in that journal during 1997-2014. 3 The percentage of the related publications in that journal. 4 The journal’s impact factor for 2014.
All the searched 1994
articles were published in a
total of 857 journals (or
conferences).
It indicates the breadth of
publication distributions as
well as the broad interests on
WPP related research from
various perspectives.
Energy Policy is the most
influential journal with a
number of 144 (7.25%)
articles.
The top academic
conference related with WPP
is the international
conference of IEEE Power
and Energy Society
General Meeting (PES).
3
3.4 Countries’ characteristics
Results and discussions
Fig. 3. The top 15 most productive countries.
The number of publications for
one country reflects their attentions and
overall strengths in the related research
fields.
The top 15 countries published a total of
1343 articles, accounting for 74.69% of
the total publications.
3
3.4 Countries’ characteristics
Results and discussions
Fig. 4. The academic collaborative relationships
among 49 countries.
The top 10 countries with more collaboration are
the US, United Kingdom, Germany, Spain,
Canada, China, Australia, Norway and
Netherlands.
The US scholars have published most cooperative
publications with their partners in China, UK,
Canada, Netherlands, Denmark and Australia.
Major European countries, including Germany,
UK, Denmark, Spain, have more mutual
collaboration due to their geographical and culture
proximity and active promotion of wind power.
China is the top 1 Asian country in this field and
the Chinese scholars have more collaboration
activities with the US, UK, Australia, Hong Kong
(as one region), and Singapore.
3
3.5 Institutions’ performances
Results and discussions
Table 2 The top 15 most productive institutions on WPP during the period of 1997-2014.
Rank Institutions Country Articles
1 Technical University of Denmark Denmark 42
2 North China Electric Power University China 26
3 Islamic Azad University Iran 26
4 Aalborg University Denmark 26
5 Carnegie Mellon University USA 23
6 IEEE - 23
7 National Renewable Energy Laboratory USA 22
8 University of Waterloo Canada 18
9 Stanford University USA 16
10 University of California USA 16
11 Argonne National Laboratory USA 16
12 Cornell University USA 16
13 University College Dublin Ireland 16
14 University of New South Wales Australia 15
15 Norwegian University of Science and Technology Norway 15
6 institutions locate in the US.
Technical University of Denmark
ranked the 1st since Denmark is the No.1
country in terms of the share of wind
power in the overall energy supply.
The North China Electric Power
University is the only one from China
although it is the second productive
institution in the world.
Only one institution is from Iran, namely,
Islamic Azad University, indicating that
the developing world still need to further
support the related studies.
3
3.6 The most cited articles
Results and discussions
The citation counts for most
high quality papers reached the
peak within five years of their
publication, mainly due to fast
academic development.
The second most cited articles
are more relevant with WPP
than the most cited articles
according to the keywords.
The most cited articles focus on
WPP more from the perspective
of renewable electricity, while
the second most cited articles
focus on the cost-benefit
analysis of wind power.
3
3.6. The most cited articles
Results and discussions
The top 2 most cited articles related with WPP in each year are illustrated. However, these
articles do not have complete representativeness.
For example, the citation counts of the first most cited article published in 2000 was less than
that of the third most cited article published in 2009.
Thus, a further analysis for the top 60 articles (their citation counts over 65) during 1997-2014
is necessary. The top 60 cited articles can touch the heart of WPP while the co-citing intensity reflect
their relationships between each other. Co-citing intensity between two articles is represented by the
number of same references. The more same references of two articles, the more similar their
research contents are.
Meanwhile, it has been observed that many real networks exhibit a concentration of links
within certain groups of nodes called communities (or clusters). The detection of the community
structure of a given network could help discover some hidden features of its topological
architecture.
3
3.6. The most cited articles
Results and discussions
Community 2Cost; Risk; Policy
Community 3Integration; Storage;
Management
Community 4Energy Security;
Sustainability
Community 1Hybrid Energy System;
Modeling; Optimization
Fig. 7. The academic co-citing network among top 60 cited articles during 1997-2014.
Note: The node size is determined by that article’s total citations. The line between two
articles means that they have at least one same reference. The thicker the line is, the
stronger the correlation is.
There are 4 communities in
the academic co-citing network
according to their co-citing
intensity relationships.
There are obvious disparity in
the research field.
However, the researches on
WPP cannot leave cost, risk,
carbon emission reduction and
environmental efficiency,
which is a comprehensive
background. A hybrid model
considering various factors is
needed.
3
3.7. Research hot point analysis
Results and discussions
Keywords’ performances
Subject 1
Subject 2
Method
Field
Purpose
Renewable Energy, 295
Electricity, 226
Solar Energy/PV, 111
Hydrogen, 53
Hydro,Huclear,Biomass, 42
Wind Energy, 224
Wind Power, 286
Wind Turbine, 73
Wind Farm, 31
Offshore Wind, 30
Energy Storage, 110
Economics, 99
Risk/Uncertainty, 86
Climate Change, 85
Electricity Price, 117
Bidding Strategy, 39
Real Time Pricing, 29
Locational Marginal
Price, 29
Feed-in Tariff, 22
Energy Security, 18 Sustainable
Development, 15
Energy Efficiency, 14
Energy Policy, 45
Environmental Policy, 27
Optimization, 162
Programming, 59
Forecasting, 51
Simulation, 46 Others, 172
Day-ahead
Electricity Market,
84
Distributed
Generation, 77
Demand Response,
65
Wind Power
Integration, 63
Smart Grid, 44
Micro Grid, 39
Electric Vehicles, 44
Fig. 9. Distributions of keywords.
Subject 1 refers to different types of
energy resource, including renewable
energy, electricity, wind energy, solar
energy and hydro energy.
Subject 2 refers to electricity market types,
including distributed power generation,
smart grid, demand response, small scaled
grid, electric vehicles , wind power
integration and day-ahead electricity
market
It demonstrates that WPP research adopts
several mainstream methods, and novel or
hybrid models are needed.
The subject of price mainly focuses on
electricity price while keywords bidding
strategy, real time pricing, and feed-in
tariff occupy have less frequency of
occurrence. However, it is inadequate with
the emerging of smart grid in new energy
policy. So, the research of wind grid-
connected for improving absorptive
capacity of wind power makes sense.
3
3.7. Research hot point analysis
Results and discussions
Keywords’ performances
Fig. 8. The power distribution between the frequencies and ranks of keywords.
The frequency of author
keywords and their ranks follow
the power law distribution. It
is clear that most keywords
were seldom used and several
keywords were frequently used.
2599 keywords only appeared
once, accounting for 77.37% of
the entire 3359 keywords.
However, the top 4 (0.12%)
most used keywords appeared
950 times
Other keywords appeared more
than 50 times include day-ahead
electricity market, optimization,
wind turbine, energy storage,
demand response and electric
vehicles.
4 Looking forward
First, changes in the international renewable energy policy determine direction and depth
of WPP research.
Since 2011, countries with wide application of wind power, such as Germany, the
US, France, UK, Denmark, and China have signed a series of renewable energy policies,
such as renewable energy act, key funding for renewable energy investment plan, and the
renewable energy roadmap, which proposed the future requirements for smart grid,
technologies, wind power grid-connected and offshore wind in the future. Because, the
rapid development of smart grid technologies provide a seamless and excellent technical
support for wind grid-connected. It becomes a hot issue that how to solve the deviation
between frequency and voltage caused by wind power output fluctuation in a more secure
grid-connected way. Overall, future research on WPP should focus on large-scale wind
energy generation and smart grid access technology to break through its intermittent. In
the meantime, establishing a market-oriented pricing mechanism for wind power grid-
connected and incentives policies simultaneously, promotes clean energy transformation.
In addition, considering the regulation among hydropower, thermal power and wind
power in the area of wind energy generation, and establishing wind power-hydropower
complementary system and wind power-solar power complementary system are
significant for wind power consumption.
4
Second, offshore wind power has enormous potential.
As for the weakness of unbalanced wind resource distribution, large land occupation,
and generating volatility on onshore wind energy, offshore wind power developed
rapidly for its avoiding these shortcomings. The development of offshore wind power
has become the consensus of the world. But the output on offshore wind is less
according to the distribution of keywords in Fig.9. Research on wind power for
technology advances, changes in project cost, price level, market access and feed-in
tariff have great potential.
Third, China’s wind power industry drives global growth.
During 2012-2013, China’s wind power downturn, inevitably, the global wind power
grew slowly. In the year of 2014, the global wind market recovered along with the
historical high of China’s wind power installed capacity. And, the global wind power
development broke out of its slump driven by China’s wind power. Thus, It becomes a
hot issue of research on China’s wind energy generation technology, feed-in tariff,
subsidy, big data analysis and internet of energy.
Looking forward
4
Fourth, strengthen the technology exchanges and cooperation among countries.
The academic cooperative literatures research on WPP is currently limited on the
US. The cooperation between other countries, such as China, Denmark, Germany,
Spain, UK and Japan, is significance for promoting their wind power development.
Fifth, integration and innovation on research methods.
Based on the results above, optimization, dynamic planning and forecasting are the
main methods on WPP. Innovation and combination of various methods, including
considering capital cost, risk assessment, carbon emission reduction and
environmental efficiency is needed.
Looking forward
Conclusions
With fast development of wind power, more academic efforts have been
made in the field of WPP recently. Under such a circumstance, it is critical to
review the most recent progress on WPP related studies.
Based on bibliometric analysis, this study presents the current
development status of WPP through content analysis involving countries,
affiliations, the most cited articles and keywords. It provides a comprehensive
review on WPP and points out future research directions.
5
Conclusions
Overall, this study could help understand the past trajectory of wind
power price research, and how the world/nations are contributing to this
research field. Combined with knowledge from experienced researchers, this
study could help them identify research gaps in the current research as well as
help guide them in establishing future research directions including integration
and innovation on research methods, strengthen the technology exchanges
and cooperation among countries, and a comprehensive study on offshore
wind power pricing, wind power grid-connected, feed-in tariff and big data
analysis.
5
LOGO Jiangsu University