  Recent years have witnessed an increasing interest in the blockchain
technology, and many blockchain-based applications have been developed to take
advantage of its decentralization, transparency, fault tolerance, and strong
security. In the field of smart grids, a plethora of proposals have emerged to
utilize blockchain for augmenting intelligent energy management, energy
trading, security and privacy protection, microgrid management, and energy
vehicles. Compared with traditional centralized approaches, blockchain-based
solutions are able to exploit the advantages of blockchain to realize better
functionality in smart grids. However, the blockchain technology itself has its
disadvantages in low processing throughput and weak privacy protection.
Therefore, it is of paramount importance to study how to integrate blockchain
with smart grids in a more effective way so that the advantages of blockchain
can be maximized and its disadvantages can be avoided.
  This article surveys the state-of-the-art solutions aiming to integrate the
emergent blockchain technology with smart grids. The goal of this survey is to
discuss the necessity of applying blockchain in different components of smart
grids, identify the challenges encountered by current solutions, and highlight
the frameworks and techniques used to integrate blockchain with smart grids. We
also present thorough comparison studies among blockchain-based solutions for
smart grids from different perspectives, with the aim to provide insights on
integrating blockchain with smart grids for different smart grid management
tasks. Finally, we list the current projects and initiatives demonstrating the
current effort from the practice side. Additionally, we draw attention to open
problems that have not yet been tackled by existing solutions, and point out
possible future research directions.
