Bid-aggregation based clearing of day-ahead electricity markets

In this work we propose a two-step alternative clearing method of day-ahead electricity markets. In the first step, using the aggregation of bids, an approximate clearing is performed, and based on the outcome of this problem, the estimates for the clearing prices of individual periods are derived. These assumptions regarding the range of clearing prices explicitly determine the acceptance indicators for a subset of the original bids. In the subsequent stage, another round of clearing is performed to determine the acceptance indicators of the remaining bids and the market clearing prices. We show that the bid-aggregation based method may result in suboptimal solution or in an infeasible problem in the second step, but we also point out that these pitfalls of the algorithm may be avoided if a different aggregation pattern is used. We propose to define multiple different aggregation patterns, and to use parallel computing to enhance the performance of the algorithm. We test the proposed approach on setups of various problem sizes, and conclude that in the case of parallel computing with 4 threads a significant gain in computational speed may be achieved, with a high success rate.