Grid Integration and Market Analysis of Adjustable-Speed Pumped Storage Hydropower: Preprint

Many of the products and services on the electrical grid are currently provided by the conventional power plants, however the response time from conventional power plants is slow compared to hydropower. Similarly, some services such as spinning reserve can be provided by modern renewable generation (wind or PV), however the renewable generation must be curtailed down, thus there is loss of opportunity to harvest clean energy while operating in spinning reserve mode. On the other hand, Adjustable Speed - Pumped Storage Hydropower (AS-PSH) can readily perform these functions while pumping or generating, thus also taking benefit of energy arbitrage which can increase system efficiency. This paper will present results from production cost models showing the effect of adding AS-PSH 50 MW in size to three regional ISO areas which have different ancillary service markets available and different generation mixes. The benefits to these market areas from the ancillary services that can be provided by the AS-PSH and also the load shifting benefits will be measured with cost savings and additional system flexibility in the day-ahead and real-time markets. The main metrics to provide this insight will be savings in the total system production cost and in variable renewable energy curtailment respectively. The simulated operation of the additional hydropower will be analyzed to determine the breakdown of system cost reduction by ancillary services provided and load shifting.