Towards a low carbon proof-of-work blockchain
Agron Gemajli, Shivam Patel, Phillip G. Bradford
TL;DR
The paper addresses the high energy costs of proof-of-work blockchains and proposes a low-carbon alternative based on a lottery-driven proof-of-virtual-machine (PoVM) model, where miners provide VM-based computation for queued jobs via Docker containers orchestrated by Kubernetes and interconnected with Skupper. The approach decouples on-chain consensus from off-chain, SLA-governed computation, enabling useful work to substitute traditional hashing tasks while maintaining blockchain-inspired accountability. A concrete prototype demonstrates the architecture and a coin-flip computation demo, highlighting how SLAs, replication, and verification concepts can validate PoVM execution. The work identifies technical gaps—most notably the lack of multiparty consensus and formal SLA verification—and outlines clear future directions, including CO2 accounting, enhanced security with multi-signature schemes, and redundancy-based validation to move toward a practical, low-carbon blockchain system.
Abstract
Proof of Work (PoW) blockchains burn a lot of energy. Proof-of-work algorithms are expensive by design and often only serve to compute blockchains. In some sense, carbon-based and non-carbon based regional electric power is fungible. So the total carbon and non-carbon electric power mix plays a role. Thus, generally PoW algorithms have large CO$_2$ footprints solely for computing blockchains. A proof of technology is described towards replacing hashcash or other PoW methods with a lottery and proof-of-VM (PoVM) emulation. PoVM emulation is a form of PoW where an autonomous blockchain miner gets a lottery ticket in exchange for providing a VM (virtual Machine) for a specified period. These VMs get their jobs from a job queue. Managing and ensuring, by concensus, that autonomous PoVMs are properly configured and running as expected gives several gaps for a complete practical system. These gaps are discussed. Our system is similar to a number of other blockchain systems. We briefly survey these systems. This paper along with our proof of technology was done as a senior design project.