# Renewable Energy and Sustainability from the Supply Side: A Critical Review and Analysis
## 3 Method and Data
### Most Productive Countries on Renewable Energies and Sustainability
In 2010, researchers affiliated with institutions from the USA, Brazil, Italy, and Canada developed articles focusing on specific types of renewable energies and their sources making different contributions to this research topic. For example, [PERSON] et al. [75] focused on wood biomass as a source of energy production, giving insights on the main factors affecting the sustainability of future commercialization of wood residue such as the availability of the wood raw material, the development of wood-based fuel markets, and expectations related to the profit. In addition, [PERSON] [76] listed a set of actions for companies and governments to be more sustainable promoting a discussion of ethanol, which is considered one of the most viable clean and renewable fuels used by society until the present. [PERSON] and [PERSON] [77] focused on wind, arguing that environmental, institutional, and cultural factors play important roles in the emergence of wind energy industries in both industrialized and emerging economies. Biopolymers were evaluated by [PERSON] [78] in terms of their chances and risks, highlighting the importance that biopolymers have gained in the industry and describing the different strategies that firms apply to employ biopolymer technology successfully. Many of the publications on renewable energies and sustainability during 2011 have a special focus on sustainability models [79; 80; 81] and sustainability assessment methodologies associated with renewable energies [82; 83; 84]. The affiliation of their authors are mainly institutions in USA (Figure 6). The year 2012 was very productive in terms of publications, with a specific set of topics being explored by a considerable number of authors affiliated with USA, Italy, Germany, and Spain, such as biofuel/bioenergy [85; 86; 87], benchmarking analysis and case studies on renewable energies [88; 89; 90], energy policies and governance [91; 92], and energetic analysis of renewable energies [93; 94]. Many articles on renewable energies and sustainability are observed also during 2017 and with different research topics. The state of the art of specific renewable energies in some countries was explored in some articles published in this year, such as biomass energy in Turkey [95] and Malaysia [96]; biofuel in Malaysia [97], Australia [98], and Sardinia [99]; hydropower in India [100]; and the energy sector in general in Romania [101]. The policies associated with renewable energies have also been explored in some articles: (i) [PERSON] et al. [102] focused on the policies related to renewable energy resources regarding their industrial processes, the role of government incentives or subsidies, and investments of companies in technology development; (ii) [PERSON] [103] highlighted policies associated with the renewable energy sector in India post-Paris negotiations; and (iii) the authors of [104] underlined the misguided goals and inefficient mechanisms of biofuel policies. The economic  
Figure 6: Temporal distribution of top 10 most productive countries of renewable energies and sustainability articles. and financial performance of the renewable energy sector has also been the focus of some of the sample articles (e.g., [101; 105; 106]). From these works, it is interesting to highlight the main conclusion drawn by [PERSON] [101], who considered that the investments in renewable energies have been considerably opportunistic, based on the wish of the government to maintain the subsidies it introduced, instead of being based on the realistic long-term financial performance of the companies in this area. It is also interesting to note that the research unit focused on in the sample articles has changed somewhat over the years. In fact, the number of articles on supply chain in the renewable energy sector has showed substantial growth. A focus on the supply chain can be found in [107] about waste paint in auto industries, in [108] focusing on the solar cell industry, and in biodiesel production using waste cooking oil [109].