International Association
for Cryptologic Research

The demand for peer-to-peer (P2P) energy trading systems (ETS) grows alongside the development of house renewable energy generation. A P2P/ETS enables its peers to trade energy freely as in a double auction market. It requires a ledger to record peers' trading history. A typical approach is relying on a decentralized ledger, e.g., blockchain, with smart contract capabilities, unavoidably incurring high costs. Therefore, motivated to build a smart contract-free system, this work proposes a novel blockchain and consensus design utilizing the double auction characteristics of P2P/ETS. Concretely, we first revisit the blockchain data structure so that it can reflect auction bids. Next, we introduce a novel mining mechanism utilizing a bid-matching problem (BMP), which requires miners to find the best combination sets of sell/buy bids according to a given scoring function. Hence, the miner who mines the best-scored block can extend the blockchain. The fundamental difference between the BMP-based mining and traditional proof-of-X schemes, e.g., work or stake, is that our protocol selects blocks instead of miners. That is, a higher-scored block has better contents (bids and transactions), thus being preferable to a lower-scored block regardless of whether the miner is honest. Finally, we analyze miners' local chain dynamics and show a bound for the score distribution of the scoring function to prove that the protocol satisfies the key properties of consensus, i.e., persistence and liveness.