Economic Analysis of Grid Level Energy Storage for the Application of Load Leveling

[摘要] The benefits that exist on behalf of energy storage appear to be nearly limitless and there is no exception to this in power systems.Energy storage can be used to flatten an electrical load by charging the storage when the system load is low and discharging the storage when the system load is high.This technique is known as load leveling and is the storage application of interest in this thesis.One of the biggest benefits that load leveling can yield is the elimination of expensive gas turbine generators.Gas turbine generators are used because they can react to drastic changes in the system load that other generators can’t.Their downfall however, is that they are more expensive than the other generators.But if the load is level enough, there is no need to use gas turbine generators because there aren’t any drastic changes in the load.Load leveling requires a storage device to have a very large capacity.In this thesis several different large storage types are studied to see which ones are best suited for the application of load leveling.Ultimately both NaS batteries and pumped hydro storage are chosen to use for this study and the results for each is compared.A theoretical double peak system load with a peak value of 1950 megawatts is used for this study. The load is leveled by discretizing the energy storage’s charging and discharging profiles and allocating the stored energy by means of dynamic programming.An economic analysis of both the original case and the case in which energy storage is used to level the load is carried out.This study shows that energy storage used for the application of load leveling can be economically beneficial depending on the type of storage that is used.Battery storage is not quite ready to be used for this application but with some improvements to the technology it could be soon.Pumped storage on the other hand is the cheapest form grid level energy storage and can generate a great deal of economic gain in today’s power systems.

[发布机构] the University of Pittsburgh