Paper 2022/1471

Peer-to-Peer Energy Trading Meets Blockchain: Consensus via Score-Based Bid Assignment

Abstract

The demand for peer-to-peer energy trading (P2PET) grows alongside the advancement of smart grids. A P2PET system enables its peers to trade energy as in a double-sided auction market by issuing auction bids to buy or sell energy. A robust public ledger, that satisfies the standard properties of persistence and liveness, is necessary for the system to record trading agreements, i.e., combinations between buy and sell bids which would form a \emph{transaction}. The Bitcoin based blockchain satisfies such properties as proven in the backbone protocol (EuroCrypt'15). However, existing blockchain-based P2PET approaches rely on general-purpose blockchains with smart contract capabilities, unavoidably incurring in high operational costs. Therefore, this work intends to design a dedicated blockchain for the ledger of P2PET. We first revisit the blockchain data structure to support auction bids. Then, we abstract the process of forming transactions, i.e., matching bids, with a score-based many-to-many Bid Assignment Problem (BAP). Leveraging our proposed BAP in addition to the corresponding scoring function, we propose a ``proof-of'' scheme, namely Proof-of-Bid-Assignment (PoBA), and design the corresponding blockchain aided protocol. The key difference from any previous work, we are aware of, is that our protocol selects blocks according to the score of their content, i.e., bids and transactions. Hence, a higher-scored block would be preferable to the underlying P2PET system regardless of whether the block's generator is honest, since, intuitively, it would increase the number of trading agreements. Finally, by modeling PoBA with a universal sampler (AsiaCrypt'16) and analyzing honest users' local chain dynamics, we prove the security of our design with respect to the standard ledger properties.