Urban energy systems (UESs) play a pivotal role in the consumption of clean energy and the promotion of energy cascade utilization. In the context of the construction and operation strategy of UESs with multiple complementary energy resources

a comprehensive assessment of the energy efficiency is of paramount importance. First

a multi-dimensional evaluation system with four primary indexes of energy utilization

environmental protection

system operation

and economic efficiency and 21 secondary indexes is constructed to comprehensively portray the UES. Considering that the evaluation system may contain a large number of indexes and that there is overlapping information among them

an energy efficiency evaluation method based on data processing

dimensionality reduction

integration of combined weights

and gray correlation analysis is proposed. This method can effectively reduce the number of calculations and improve the accuracy of energy efficiency assessments. Third

a demonstration project for a UES in China is presented. The energy efficiency of each scenario is assessed using six operational scenarios. The results show that Scenario 5

in which parks operate independently and investors build shared energy-storage equipment

has the best results and is best suited for green and low-carbon development. The results of the comparative assessment methods show that the proposed method provides a good energy efficiency assessment. This study provides a reference for the optimal planning

construction

and operation of UESs with multiple energy sources.