Blockchain (BC) has developed to a certified choice for dispersed, peer-to-peer, disseminated translucent record systems with various data structures. Green computing (GC) is currently the concentrated expectant approach for the incorporation of smart expertise in a different and dispersed world of power usage. Security is becoming a foremost dispute in adopting multiple tenants in a green computing environment. A multi-tenancy is considered as the most essential characteristic of green computing, but at present, multi-tenancy is facing challenges from privacy and security domains, which may hinder the advancement of going green. Going green has huge benefits such as energy efficiency, eco-friendliness, multi-tenancy, recycling, and virtualization. Hence, applying green computing technology such as blockchain can improve operational security in a cloud environment. In this paper, therefore, various forms of green computing, the need for green computing, benefits, and security concerns of multi-tenancy in cloud environments are discussed. Finally, this paper proposed blockchain technology as a method to deal with the security and privacy challenges in a multi-tenant environment. The study implemented blockchain in a cloud environment with the use of Ganache and MetaMask to create a dummy secure account for each cloud tenant.