# State-Of-The-Art and Prospects for Peer-To-Peer Transaction-Based Energy System
## 8 Challenges Facing Energy Trading and Sharing and Future Directions  
From the review conducted, this paper argues that it is paramount to have enabling technologies and required frameworks before energy trading and sharing among proactive prosumers can be realized. In this section, some gaps in the literature deterring the achievement of optimal energy exchange among prosumers are identified. These gaps are briefly discussed below. In addition, Table 3 presents some drawbacks to some methods used in the literature for TE. \begin{table}
\begin{tabular}{p{56.9 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt}} \hline \hline
**Ref.** & **Purpose** & **Methods** & **Comments** \\ \hline
[11] & Energy sharing & Centralized cluster & Lack of pricing mechanism. \\ \hline
[78; 107] & Energy sharing & Central control/ESP & Does not consider power loss. \\ \hline
[6] & Energy trading & Autonomous cooperative & Lack of pricing mechanism. \\ \hline
[8] & Energy trading & Central market/central auctioneer & They used the naive auction algorithm. This can only be applied with an equal number of buyers and sellers. What happens when the numbers of buyers and sellers are not equal? \\ \hline
[36] & Energy trading & Central control & Uses static parameters not dynamic, i.e., with every change in the parameters, the optimization model would be re-run to reflect the changes. This is not computationally efficient. \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Drawbacks of some methods used in the literature. Figure 6: A proposed platform algorithm for distributed energy transaction and management. 1. As reported in [10], existing literature works assume perfect communication between prosumers exchanging energy [10]. The research community needs to further investigate scalable architectures for the trading network. The enabling communication system must not only be ubiquitous, but also deliver low latency and support coexistence with different generations of power and ICT systems. Actualization of 5G wireless systems may provide a giant leap in this direction. In addition, network formation games can be applied to enable information coordination between prosumers [84]. Furthermore, to achieve prosumer communication within the communication infrastructure, a unified messaging framework is required. The OpenADR (open automated demand response) is a potential model to fill this gap. The OpenADR provides a standardized interface that allows electricity providers and DSOs to communicate demand response events to their customers over IP-based communication networks [32; 108]. Moreover, additional optimization techniques such as advanced linear programming, nonlinear convex optimization, Lagrange duality, the KKT (Karush-Kuhn-Tucker) optimality condition, the gradient algorithm, the interior point algorithm, geometric programming, semidefinite programming, robust optimization and dynamic programming need to be investigated. 2. Most research tends not to consider pricing mechanisms during energy trading. Advanced techniques can be employed for generating the electricity prices as the impact of the generated price on the energy profiles of the prosumers is also of interest. 3. In matching buyers to sellers, strategies based on auction theory are commonly used. However, their efficiency can be improved by incorporating a prediction algorithm to forecast energy demand and price in the MG [109]. Furthermore, future game theory applications in prosumer energy trading could involve several types of games such as facility-location games, Stackelberg games, advanced hash games, and others. 4. Another prominent research gap in the literature is security and privacy of prosumers' data. More research is required to investigate optimal ways of ensuring privacy and security in protecting prosumers' data during and after energy exchange. 5. More research on robust and lightweight distributed algorithms that can efficiently represent different energy trading scenarios (competitive or collaborative) is desired. 6.