A systematic literature review of blockchain technology and energy efficiency based on consensus mechanisms, architectural innovations, and sustainable solutions

Blockchain technology offers promising solutions for decentralization and transparency but faces increasing scrutiny due to the high energy consumption of consensus mechanisms like Proof-of-Work (PoW), raising concerns about environmental sustainability. This study aims to evaluate and compare the energy efficiency of major blockchain consensus mechanisms and architectural innovations, while also examining regulatory efforts that promote greener blockchain systems. A systematic literature review was conducted using the PRISMA framework, synthesizing 53 peer-reviewed studies and industry reports published between 2018 and 2024. The review focused on eight consensus mechanisms—PoW, PoS, DPoS, PoA, PoSpace, DAGs, BFT, and PoH—and architectural solutions such as sharding, rollups, and modular blockchain frameworks. A structured quality assessment was applied to ensure methodological rigor. Findings indicate that energy-efficient mechanisms like PoS and DAGs can reduce energy use by over 99% compared to PoW, although trade-offs in decentralization and security remain. Architectural enhancements such as Layer-2 scaling and sharding improve energy efficiency but introduce additional complexity. Regulatory frameworks, including the EU’s MiCA regulation and the Crypto Climate Accord, encourage the adoption of renewable energy and transparent energy reporting. The study concludes that blockchain can support global sustainability goals through the integration of energy-efficient consensus models, policy compliance, and future innovations in decentralized energy solutions.