  The concept of smart grid has been introduced as a new vision of the
conventional power grid to figure out an efficient way of integrating green and
renewable energy technologies. In this way, Internet-connected smart grid, also
called energy Internet, is also emerging as an innovative approach to ensure
the energy from anywhere at any time. The ultimate goal of these developments
is to build a sustainable society. However, integrating and coordinating a
large number of growing connections can be a challenging issue for the
traditional centralized grid system. Consequently, the smart grid is undergoing
a transformation to the decentralized topology from its centralized form. On
the other hand, blockchain has some excellent features which make it a
promising application for smart grid paradigm. In this paper, we aim to provide
a comprehensive survey on application of blockchain in smart grid. As such, we
identify the significant security challenges of smart grid scenarios that can
be addressed by blockchain. Then, we present a number of blockchain-based
recent research works presented in different literatures addressing security
issues in the area of smart grid. We also summarize several related practical
projects, trials, and products that have been emerged recently. Finally, we
discuss essential research challenges and future directions of applying
blockchain to smart grid security issues.
