Reviewing the opportunities, challenges, and future directions for the digitalization of energy

Smart grids are the backbone of existing energy production and supply scenario in today's society. Gradual increasing demand of energy has certainly emphasized the significance and provenance of reliability and predictive aspects over smart grids. Conventional smart grids under perform in terms of self-aware behavior, especially in delay tolerance, energy requirement, and dissemination of monitoring notions. Highly distributed geographical distribution sometimes cause problems for smart grids to provide necessary services to both the consumers and prosumers. Internet of Things (IoT) is thus integrated with smart grids to facilitate distributed monitoring services for smooth running of the smart grid. Although, IoT has remarkably supported smart grids to perform smarter than ever, it lacks in security, decentralization, transparency, and trust-less approaches. Thus, blockchain is envisaged to leverage minimizing such gaps and to pave new horizon in the blockchain-IoT enabled smart grid monitoring. In this paper, we investigate how blockchain and IoT together can improve existing smart grid ecosystem toward facilitation of better monitoring services. We do this via a Systematic Literature Review. Firstly, we present preliminaries behind the study, followed by in-depth review of different domains of IoT-based smart grid monitoring. Next, we discuss various attributes of blockchain-IoT derived smart grid management schemes. Then, we discuss possible opportunities and benefits of using blockchain with respect to blockchain-IoT based smart grid monitoring. Finally, we illustrate open research challenges and future directions in the aforementioned aspects. The article concludes that with certain changes in current blockchain technology, it can surely encompass the direction of enhanced monitoring of IoT based smart grid.