Feasibility Study of Pumped Hydro Energy Storage for Ramea: Wind-Diesel Hybrid Power Systemud

摘要

Ramea is a small island in southern Newfoundland. Since 2004, it has a wind-diesel hybrid powerudsystem to provide power for approximately 600 inhabitants. The average wind energy contribution to the totaludsupplied load is less than 10%. Newfoundland and Labrador Hydro with the support of ACOA has upgraded theudRamea hybrid power system. They have added three more 100kW wind turbines and a hydrogen energy storageudsystem. The new system is still under construction and it is expected to be fully operational by fall 2010. In audhydrogen energy storage system, excess wind generated electricity is converted to hydrogen using a 70% efficientudelectrolyzer. The hydrogen produced is compressed and stored in tanks. Compressed hydrogen is used to run audless than 35% efficient hydrogen engine as needed. It is expected that overall conversion efficiency of the energyudstorage system will be less than 25%. For a remote location like Ramea where there are few hills with a heightudabove 60m a pumped hydro energy storage is possible. The overall efficiency of a pumped hydro energy storageudsystem is typically above 70%.udIn this research we present a study of a pumped hydro long-term energy storage system for Ramea winddieseludsystem. We determined optimal energy storage requirements for the Ramea hybrid power system, identifieduda site that can be used for pumped hydro energy storage and calculated the required storage capacity. We present auddetailed analysis and dynamic simulation of the proposed wind diesel pumped hydro system. Sizing of a pumpedudhydro system indicates that a 150kW pumped hydro storage system at Ramea can achieve a renewable energyudfraction to 37%. Such a system will need a 3932m3 water reservoir at a height of 63m (on top of Man of War Hill)udand it will provide 150kW for 3.14 hours. Dynamic system simulations indicate acceptable power quality after anudaddition of a pumped hydro storage system.udWe think a pumped hydro energy storage system for Ramea is a much better choice than a hydrogenudenergy storage system. Such a system will have a higher overall efficiency and could be maintained using localudtechnical expertise, therefore a more appropriate technology for Ramea.