This paper analyzes the impact of an independently-operated large-scale energy storage system on the electricity prices of a fully competitive pool-based electricity market. From a consumer's perspective, the impact of storage operation on energy cost is investigated. The changes in the revenue of generation units and entities caused due to the arbitrage operation of storage facility are also explored. In the current study, we have considered an optimization-based scheme to schedule the operation of a large-scale storage system. Also, a number of ad-hoc strategies to participate in the energy market are examined for the sake of comparison. Modeling the impacts of a large-scale energy storage system can inform planners and operators of the potential effects of storage on the rest of the system and help them to use storage most effectively. These analyses can also inform regulators and policy-makers of the potential societal costs and benefits to energy storage deployments that are not necessarily monetizable by the energy storage owner. (C) 2017 Elsevier Ltd. All rights reserved.