Benchmarking the operational expenditures of Brazilian transmission utilities by using DEA models

•Transmission utilities Operational Expenditure efficiency evaluation by DEA models.•New representation of the quality of service, capacity and grid length in DEA model.•Results for a panel data over the period 2013–2016 with 14 Brazilian TRANSCOS.•Results from several DEA models: CRS, VRS, NDRS and cross-efficiency analysis.•Definition of a new metric to calculate TRANSCOS final efficiency scores. In Brazil, the transmission assets are remunerated for their availability regardless of the full utilization of their capacities. The annual allowed revenue for each transmission utility is determined by the Brazilian Electricity Regulatory Agency (ANEEL). ANEEL has been using Data Envelopment Analysis (DEA) to define the regulatory operational expenditure (OPEX) for each utility, a key element for the annual allowed revenue assessment. Based on the ANEEL's DEA model this work proposes improvements in representing the quality of service, transmission capacity and transmission network length in the DEA model. Furthermore, this paper presents a more robust methodology to evaluate the regulatory operational expenditure of transmission utilities by applying several distinct DEA models; then a global efficiency score is defined by the geometric mean of the efficiency scores resulting from the set of DEA models analyzed. The performance of the proposed approach is illustrated with real data of the Brazilian transmission utilities.