Energy storage requirements for in-stream tidal generation on a limited capacity electricity grid

This study presents the modeling and analysis of an ESS (energy storage system) for a TEC (tidal energy converter) to be installed in the Bay of Fundy, Canada. The electricity distribution grid that services the region has a minimum annual electricity demand of 0.9 MW. Policy limits the installation of renewable electricity generators to 0.9 MW at this site. An existing 0.9 MW WEC (wind energy converter) occupies this capacity, inhibiting further installations. The use of an ESS enables the installation of a 0.5 MW TEC by ensuring the combined electricity output from WEC and TEC does not exceed 0.9 MW. The objective of this study is to model the system and determine the characteristics of the ESS capacity, power, and cyclic nature. The WEC and TEC are modeled based on measured and simulated wind and tidal speed data respectively. An ESS is modeled to de-couple the TEC output from the grid demand. A curtailment analysis is conducted for various ESS capacity and power sizes to determine the economic benefit. Avoidance of all curtailment requires nearly 7 MWh of storage. Significant economic benefit may be found by reducing the ESS to less than 3 MWh, resulting in minor curtailment. (C) 2013 Elsevier Ltd. All rights reserved.