# Renewable Energy and Sustainability from the Supply Side: A Critical Review and Analysis
## 4 The Most Important Topics and Analysis
### Relationship between the Sustainability Dimensions and the Level of Countries' Development  
This analysis seeks to know if there is a relationship between the dimension of sustainability focused on in the sample articles and the development level of countries (RQ2) (Figure 8). Two criteria were used to identify the dimensions of sustainability focused on in the sample:  
1. presence of the following phrases in the title, abstract, or keywords: \"economic sustainability\", \"social sustainability\", \"environmental sustainability\"; and
2. mention in the article's title of the word \"sustainability\" and in the abstract or keywords some practices within each dimension of sustainability.  
As shown in Figure 8, in the articles focusing on high-income countries (i.e., Australia, Canada, Finland, Italy, USA, Denmark, Netherlands, Sweden, Germany, etc.), the three dimensions of sustainability are explored, mostly on the environmental dimension of sustainability [150; 151; 152; 153; 154; 155; 40]. Additionally, in the articles developed about low-income countries (Rwanda, Senegal, Ethiopia, Indonesia, etc.), the topic of renewable energies and sustainability hasbeen less explored. Nevertheless, in the few articles developed in these countries, environmental sustainability is also the most explored [153; 154; 155]. Moreover, considering all the articles that comprise our sample, the environmental dimension of sustainability has been the most studied, followed by the economic one.  
It is also interesting to note that the social dimension of sustainability is explored mainly in articles focusing on high and upper-middle income countries [156; 124]. Summing up, the higher is the developmental level of the country, the more concern there is with the environmental dimension of sustainability. The same is observed in our sample regarding the economic dimension of sustainability, but with much less frequency (see [157; 158; 159; 160; 161; 111; 117; 118; 119; 120; 121; 122; 123; 124; 125; 126; 127; 128; 129; 130; 131; 132; 133; 134; 135; 136; 137; 138; 139; 140; 141; 142; 143; 144; 145; 146; 147; 148; 149; 150; 151; 152; 153; 154; 155; 156; 157; 158; 159; 160; 161]). This is consistent with the keyword co-occurrence network shown in Figure 4, where social concerns did not explicitly emerge.  
According to the analysis, there is no clear relationship between the dimension of sustainability focused on and the development level of countries. It is observed that the environmental dimension is always the most focused on (followed by the economic one), regardless of the development level of the country.  
Summing up, in the articles focusing on high-income countries, the three dimensions of sustainability are explored, but with a higher predominance of the environmental dimension of sustainability. Contrarily, in the low-income countries, the topic of renewable energies and sustainability has been less explored, but the environmental sustainability is still the most explored. Moreover, in our sample, the environmental dimension of sustainability has been the most studied, followed by the economic dimension, but with less frequency. The social dimension of sustainability is studied only in articles focusing on high and upper-middle income countries. In other words, the higher is the developmental level of the country, the more concern there is with the environmental dimension of sustainability.