Security constrained unit commitment (SCUC) is a core aspect of spot market clearing. Under the traditional centralized solving method

the SCUC model solving process is in a "black box state". This makes it difficult to verify the optimality of the results

and market participants may question the reliability of the solution.. To address the above challenges

this paper proposes a blockchain-based unit commitment algorithm for trustworthy clearing in spot market. First

the concept of "on-chain partitioning for optimization and off-chain parallel fault-tolerant solving" is proposed. A SCUC solving architecture based on on-chain and off-chain collaboration is established to overcome the limitations of traditional blockchain technologies in supporting SCUC tasks. Then

a fault-tolerant partitioning method for the unit commitment solution space is developed

along with an optimality proof

to balance the reliability of SCUC solutions and the efficiency of the solving process within the blockchain environment. Finally

a corresponding trustworthy SCUC solving smart contract is designed. The simulation results of the proposed trustworthy SCUC algorithm demonstrate its advantages in verifiable optimality

Byzantine fault tolerance

and solving efficiency.