Towards a Green Blockchain: A Review of Consensus Mechanisms and their Energy Consumption

Organizations all over the world are under pressure to reduce their use of non-renewable energy sources and carbon emissions into the atmosphere due to its increasing negative impact on the ongoing climate crisis. Blockchain is a disruptive technology popularised by its use in Bitcoin, which has subsequently been adopted for various use cases. However, recently Blockchain has started attracting negative attention due to its propensity for high energy consumption depending on the adopted consensus mechanism. In this work, we explore the need for green (sustainable) Blockchain by comprehensively reviewing the various existing consensus mechanisms and their energy consumption to present a framework that will contribute towards developing more sustainable and environment friendly Blockchain-enabled systems.