Verifiable proofs for the energy supply chain: small proofs brings you a long way

We describe a solution for secure and verifiable handling of energy certificates. Such certificates are increasingly used to claim and prove responsible use of green energy, and there is a strong need for transparency and public verifiability. While the proposed solution is designed for handling electricity it applies to different types of energy as well and the concepts may also be applied to other domains. Transmission System Operators are trusted to record consumption and production of electricity. The movement from volume-based MWh yearly certificates to spot-market aligned hourly or 15 min time-volume based intervals, creates challenges in relation to handling large amounts of data and subsequent transactions. Small discrete intervals gives the certification increased accuracy of energy consumption, as a means to prevent greenwashing, with the cost of higher amounts of transactional data and complexity. To ensure trust in the certification, these certificates must in addition be unique and publicly verifiable. This paper describes how blockchain technology can be used to create the required transparency and public verifiability. We show how large amounts of data can be efficiently handled on blockchains and how confidential data such as the amount of used energy in the certificates can be protected, ensuring privacy and correctness of the certificates.