Considerations to optimize electric motor compression stations
Gas compression stations can be designed either using gas turbines or electric motors as compressor drivers, the latter being more and more popular in Europe to avoid NOx and CO2 emissions. Once the primary energy is selected, compression station operator has to evaluate carefully the different options as cost of electricity over life time represents a significant portion of TOTEX (as defined in the publication at ASME Turbo Expo 2013 Elector compression a challenging alternative: how and why to choose a GT or an EM to drive a compressor). As a consequence the operating profile and versatility of the needs should be considered for the choice of the optimum solution. The paper proposes to evaluate the pro’s and con’s among the following electrical motor compressor technologies: Fixed speed motor with hydraulic speed variation; VSDS with speed increaser; high speed gearless solutions. For each solution a comparison will be made in terms of operating envelop, overall energy performance at design points and also at various off design conditions. In addition, to complete the overall operating cost, an assessment of the predictive maintenance and environmental impact will be presented. Ultimately some guidelines will be given to help the selection of technology for compression stations.