## 5 Conclusions  
The electricity storage methods have presented great feasibility concerning seasonal power generation. Therefore, V2G technology, which has the storage of electricity in batteries, has numerous benefits to society, such as improving electrical quality, reducing environmental impacts, and providing support in case of occasional interruptions in the electricity supply. This technology contributes positively to the insertion of EVs, replacing the increase in energy consumption, which in turn increases the expenditure on electricity and thus brings the feeling of savings in the search for energy sustainability. However, there are still numerous unanswered questions related to all the variables involving the implementation and viability of this technology. As noted, barriers still exist to the future of EV and energy storage technologies. For V2G, technical, economic, social, and regulatory barriers can be identified as points of improvement for the future. Among these, battery degradation and charging efficiency can be characterized as technical issues. On the economic side, it is not yet clear what the relation is between costs and benefits and how they can be transformed into a business model. In the social area, there is still a lack of research on the V2G technology, making it initially necessary to provide knowledge for disseminating the technology among possible users. This will be the main issue for future viability. Finally, environmental regulation is a major barrier to this technology. Several aspects have a direct impact on economic viability and the business model, such as the value of taxes and the lack of regulation regarding the use of electric energy storage technologies. In this work, it was possible to divide and to characterize V2G in terms of both the demand side and the supply side, always based on the four main dimensions: technical, economic, environmental, social, and political. With this division, the technology was detailed in different subcategories, thus allowing for a more comprehensive view of the negative impacts, benefits, and barriers to energy sustainability improvements. Considering the technical and economic scopes, the variety of factors analyzed corroborate improvements for both the demand and supply side. Points such as frequency regulation, peak shaving and seasonal energy storage are well covered by V2G on the supply side. On the demand side, awareness, and better knowledge on the part of users are necessary. Conversely, this technology is simple to operate and can offer the user a feeling of comfort about the availability of electrical energy--better quality energy and electrical supply in the event of a possible network outage. In environmental terms, there are practically no impacts related to physical occupation, since the V2G is a small device installed inside the residential or commercial area. Regarding air emissions, the technology does not directly impact the environment, but indirectly, there can be a reduction in GHG emissions. The greatest terrestrial impact would be related to possible battery discharges. As the technology increases the charge and discharge ratio of the battery over time, greater degradation of these batteries can be generated, and this can \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Supply** & & **Supply Side** & & **Demand Side** \\ \hline \multirow{3}{*}{Economic Technical} & – & Frequency regulation & – & Simple Operation \\  & – & Peak shaving & – & Comfort \\  & – & Seasonal energy storage & – & Power quality \\ \hline \multirow{3}{*}{Environmental} & – & Possible increase in battery & – & \\  & & disposal & – & Air quality improvements \\ \hline \multirow{3}{*}{Social} & – & Connectivity to the current & – & High cost \\  & – & Cybersecurity & – & Understanding of technology \\ \hline \multirow{3}{*}{Policy} & – & Regulation & – & Investments \\  & & & – & Job creation \\ \cline{1-1}  & & & – & Development of the HDI \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Summary of results.