## 5 Methodological Review of Existing Literature
The IEA report addressed EV results on charging at low demand times, the variable use of RES for reliability, and Demand-Side Response (DSR) aspects as a means of EV charging control [115]. **2021-2022**: An acceleration in scientific output is observed during this period. Specific issues regarding how networks are affected by alternating EV charges with high-capacity batteries emerge as a new concept to be addressed [116]. On the other hand, research on aspects such as the characterization of several EVs and their supraharmonic emissions [117], which in previous years were not easy to predict, could be derived from observations of real technologies integrated at scale. Regarding the yellow series, a logical reduction in the number of articles is observed, with gradual growth from 2006 until 2022, indicating that the three search terms have generated continually increasing interest in the scientific community. Figure 11: Chronological publication analysis of ‘electric vehicle’ plus ‘electrical networks’ (series in blue); the series in yellow includes the same terms plus ‘renewables’. Considering only review articles that already include consolidated progress from previous years in different aspects, the two series are shown in Figure 12.  
Both bar graphs correspond to Series 1 and 2 seen previously, but with only review articles included. For this study, we only selected the articles corresponding to the orange series, as it incorporates the criteria we searched for and the number of studies is manageable, allowing for selection of only the most appropriate. Our meta-analysis covered 2012 to 2022, comprising the years of greatest EV development and progression. Up to four articles per year were selected proportionally to the number of articles published (except the first years), as indicated in Table 2, based on quality, the content of the publications, the number of citations, and a reasonable geographical distribution reflecting the global research diversity, as can be seen from Tables A1-A6 and in Figure 13. The countries of origin of the selected review papers were USA, Canada, Colombia, China, Australia, India, Pakistan, Malaysia, Denmark, France, Sweden, Germany, Italy, and Spain representing an even distribution of knowledge from across the world. Regarding the fields in which the authors of the review articles worked, 96.88% were researchers at their respective universities, while the remaining 3.12% worked in the electrical industry. \begin{table}
\begin{tabular}{c c c c c c c c c c c c} \hline \hline
**Year** & **2012** & **2013** & **2014** & **2015** & **2016** & **2017** & **2018** & **2019** & **2020** & **2021** & **2022** & **Total** \\ \hline
**Number of articles** & \(1\) & 2 & 3 & 3 & 3 & 3 & 4 & 4 & 3 & 3 & 32 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Number of review articles selected per year. Figure 12: Chronological publication analysis of ‘electric vehicle’ plus ‘electrical networks’ plus ‘review’ papers (series in blue). The series in orange shows the same terms plus ‘renewables’ for the period from 2012 to 2022. In this review, eight main categories were studied over time, as in our view they include the essential aspects of both EVs and their integration into electrical networks and RES effects. Certain categories were subdivided into other subcategories to collect concepts and details that may be interesting to follow and research. We show these elements in Table 3, with the same colors subsequently used in the other graphs for data analysis. **Simulations**: This category provides tools to predict future effects by simulating scenarios of interest, anticipating the best technical and economic solutions.