Optimal placement of energy storage and demand response in the Pacific Northwest

As more and more wind is added onto the transmission grid, there has been an increasing impact for system operators with respect to dealing with the additional variability from wind energy. Transmission line thermal violation is one of the problems that should be considered when integrating variable wind power. It is found that large controllable loads or energy storage resources can provide a large benefit to the grid during times of acute stress. Sourcing or sinking power at critical buses during critical times could make a difference between grid collapse and stable operation. This paper builds a reduced power flow model for the Pacific Northwest (PNW) area to identify transmission line congestion in stressed scenarios, and utilizes a sensitivity analysis method to investigate if adding energy storage devices to certain locations contributes to reducing the transmission congestion. System congestion is evaluated as a function of injected power at many different buses. Simulation results reveal critical locations have the capability to improve congestion with the addition of energy storage or controllable load.