# Blockchain Application in Internet of Vehicles: Challenges, Contributions and Current Limitations
## 5 Findings and Future Directions  
### Review Findings: Limitations of Using Blockchain in IoV-Assisted Smart Grid  
As stated in the previous Sections, over the past few years, blockchain has emerged as a transformative technology in the context of the smart energy grids and IoV in particular. Blockchain technology, in combination with consensus algorithms, cryptographic techniques and smart contracts, has enabled end-users to interact without the intervention of a centralized authority or middleman. Despite the fact that no middleman are present during runtime and operation, blockchain-based systems constantly rely on the validity of the predefined rules [70]. As a result, it is critical to ensure that they are trustworthy, secure and reliable. Moreover, blockchain technology is still in its early stages and is dealing with a variety of issues, such as reduced transaction loads [98]. Furthermore, the complexity of current protocols and solutions continues to be a challenge for academics and industry players. Despite the fact that a lot of work has been conducted, blockchain is still experiencing some limitations, as well as some potential restrictions related to its integration in the smart grid [99]. In this Section, we discuss, in detail, the research limitations of blockchain in IoV-assisted smart grids, which must be addressed before the broad adoption in large scale environments. The authors believe that the presented limitations are worthy of future study efforts towards blockchain integration in IoV-assisted smart grids. The identified limitations in the area of blockchain and IoV-assisted smart grids are depicted in Figure 12 and described below:  
Figure 12: Limitations of using blockchain in IoV-assisted smart grids. **Limitation1--Legal and Regulatory Aspects:** Significant limitations to technology adoption arise in both the regulatory and legal spheres. Consumers' active engagement in electricity markets is encouraged by regulators [21]. Furthermore, several policy-makers have developed supporting measures for local or community energy systems [100; 101], with the goal of lowering consumer costs, promoting low-carbon technology and eliminating fuel poverty. Nonetheless, when it comes to alterations in the main power grid, the present grid legal system does not enable energy trading from prosumers to consumers and does not encourage the incorporation of blockchain and smart contracts into the energy grid [12]. New forms of contracts, specifically for the P2P trading system and the decentralized interactions between the IoV entities, must be established, since in the present grid system, such issues are strictly regulated. Furthermore, regulatory bodies are in charge of establishing consumer data protection standards. The new EU regulation on consumer data (i.e., General Data Protection Regulation (GDPR)) is a recent example. Users of blockchain systems should be recognized in order to account for their responsibilities, but consumer information, such as agreed-upon pricing between an energy supplier and a consumer, should be kept private [102]. Towards this direction, further investigation is also needed regarding the legality and regulation of the smart contracts, since they should be incorporated into legal code, in order to guarantee compliance with the law and GDPR [103; 104]. Therefore, even if blockchain technology has already shown its value in smart grids and IoV, adopting the technology into the main grid is extremely difficult without revised legal and regulatory mechanisms. **Limitation 2--Performance:** Integrating blockchain into IoV-assisted smart grids necessitates the capacity to handle a huge volume of data and transactions in a rapidly changing environment occupied by moving cars. This is one of the current restrictions of blockchain technology in terms of immediately integrating it with IoV [59]. As a consequence of the reliance on enormous data and mobility, the performance levels of the blockchain-enabled IoV network are just as essential as its privacy and security [43; 105].