Optimal scheduling of variable speed pumped storage, solar and wind energy system

The entry of renewable energy sources in the power sector has significantly affected the inter-connected power system's safety and stability as renewable energy sources tend to generate variable power. The variability of power inflicts severe challenges for the scheduling of renewable sources. A pumped storage hydro plant (PSP) can help in integrating the variable renewable energy and balance the demand and generation on a day-ahead (DA) or real-time basis through fast response generation. An optimal PSP operation schedule has been obtained to increase the power producer's profit by formulating it as a mixed-integer problem. The mathematical problem formulation for the hybrid system with solar, wind, and PSP operation has been made, considering the next day's market schedule. The revenue has been computed by utilizing the energy of solar, wind, and PSP. A comparative study for the profit earned depending upon the power is regulated or not, using variable speed technology, during the pumping mode has been presented. The grid power has been utilized for the pumping operation of the pumped storage plant. A penalty factor has been utilized for the mismatch in the demand and generation. The analysis shows that the variable speed operation of PSP during pumping mode has increased the net profit by 12% and reduced the charges paid toward the pumping operation by 19% compared to the fixed speed operation and a rise of 3% in profit and 5% decline in pump charges have been recorded compared to twospeed operation.

Automated summary

The entry of renewable energy sources has significantly impacted the safety and stability of the power sector, with pumped storage hydro plants proving to be effective in balancing demand and generation. The study shows that variable speed operation can increase net profit compared to fixed speed operation.