**4. Results**

### *4.1. Results of the Bibliometric Analysis*

The bibliometric analysis is generated on 671 articles available on the Web of Science database, which resulted after using the terms "energy", "emission\*" and "economy" in the query and refining the results after the "relationship" filter word in the 1975–May 2019 time frame. This search allowed to keep only the results with a model included. One may see that there is an increased interest from research for this topic, as several authors try to expose possible models for determining the relationships between the three areas considering different influencing factors.

Considering the Web of Science categories of research, as presented in Figure 1, 38.75% of the articles are related to the environmental sciences area of interest, followed by energy fuels (31.89%), green sustainable science technology (23.55%), economics (21.76%) and environmental studies (18.93%). The other areas of interest have a lower percentage, 19 of the areas of interest have less than 5% of the articles found under the mentioned conditions. Following the previous mentioned facts, one may understand that there are several research areas interested in determining the relationship between the three components (energy consumption, emissions and economy), and they may be grouped either under the environmental studies/ecology umbrella, either under the socio-economic studies umbrella.

Source: Our own quantitative data processing of the 671 article abstracts downloaded from Web of Science.

#### **Figure 1.** Percentage of articles in the Web of Science research categories.

The interest in this topic has increased in recent years, as one may see in Figure 2. The first article appeared in 1994, and until 2010 the number of articles per year remained under 8, only 8.64% being published in this time period. In 2010 the number of articles reached 26, and it sky-rocketed in 2017 (110 papers) and 2018 (128 articles). In 2019, until May, there were already 55 articles published on this area of interest. The significant increase of interest in the area may come from the higher pressure posed by the current consumption pattern and the need to find better ways of living, as well as from the different options of renewable energy presented by the researchers.

From the total number of papers, almost 74.5% (500) are journal articles, 17.75% (119) are conference proceeding papers, 9.25% (62) are reviews, while less than 2% are other types of papers, such as book chapters.

Source: Our own quantitative data processing of the 671 article abstracts downloaded from the Web of Science.

**Figure 2.** Publishing years.

The most prolific ten authors on this field, as shown by the analysis, have more than five articles written in this area of interest. In Figure 3, it can be seen that Shahbaz M has is on the top with, 17 articles (2.53%) written on the topic, followed by Ozturk I with 16 (2.39%) and Lin Bq with nine (1.34%) articles. It must be mentioned that all of the authors who published in this area of interest have at least four (0.60%) articles written on the topic, which can be understood as an offering field and a dynamic one, which needs to be constantly analysed.

Source: Our own quantitative data processing of the 671 article abstracts downloaded from the Web of Science.

#### **Figure 3.** Publishing authors.

The source countries for the articles written in this field come from The People's Republic of China, where around 42.62% (286) of the articles have this source country. The following source country is the USA, with a dramatic difference of approximately 29%, as 12.97% (87) of the articles were written by authors of this country. The top three is completed by Turkey with 6.86% (46) of the articles being

written here. Other countries, where the authors show an increased interest in this area of research, are Australia, England, Malaysia, Pakistan, Spain, Taiwan, France and India, as it can be seen in Figure 4. Even if most articles come from China, the first two authors in this area have different origins. Yet, the highest proportion of authors comes from this country.

Source: Our own quantitative data processing of the 671 article abstracts downloaded from the Web of Science.

#### **Figure 4.** Publishing countries.

More than 99% of the research articles analysed are published in English, as the common language of researchers around the world. Only 0.3% of the studies are published in Chinese, 0.3% in German, 0.15% in Spanish and 0.15% in Turkish.

By using the Vosviewer software, the most used concepts in the analysed articles will be exposed on a network map presented in Figure 5. From the total number of words used in the 671 articles, 12,959, on the map are included only those terms which appear at least 15 times in the analysed corpus.

Source: Our own data processing of the 671 article abstracts downloaded from the Web of Science with Vosviewer.

**Figure 5.** Most used concepts-network map.

On the map, the most used concepts in the analysed paper abstracts are gathered in three main groups, differentiated by colours. In red, there are several focal points: Emission, energy, policy, consumption, role, level, scenario and production (terms such as model, paper and analysis may come from the article description and are not relevant for the current analysis). One may say that the macro elements of the "energy system" are included in the red cluster, from the resources and production, to the consumption and the emissions. In blue, there are two types of terms, one related to possible producers of emissions, such as China or Beijing—with direct names and county, regions, city—ass general geographical structures or industry, industrial structure—as economic sources of emissions. The second type is related to possible solutions of improvement, such as the following terms: Low carbon economy, change, development, efficiency, emission reduction or energy saving. In green, the group is formed mostly by the economic related concepts, such as: Economy, economic growth, energy consumption, growth, financial development or country.

It is important to mention that the term relationship is in the middle of the map and it connects all the focal point of the current research (energy, emission and economy), but also other important aspects that prove the right selection of papers for this analysis, such as: Model, variable, analysis or granger causality test.
