Industrial & Engineering Chemistry Research, Vol.56, No.8, 2310-2330, 2017
Integration of Decentralized Energy Systems with Utility-Scale Energy Storage through Underground Hydrogen Natural Gas Co-Storage Using the Energy Hub Approach
Community power is considered to be an important mechanism that can provide energy for communities using decentralized renewable energy systems and a step forward toward a sustainable future. Decentralized power systems are characterized by generating power near the demand centers, providing energy to satisfy local energy requirements. The decentralized energy system can operate with interactions with the local grid, in which it feeds surplus power generated to it, or it can behave as a stand-alone isolated energy system. The development of community power requires the consideration of several sustainability criteria in order to meet the minimum requirements that satisfy communities' demands and maximize energy generation benefits. These criteria include cost effectiveness, risk to the environment and humans, scaling, efficiency, and resilience. Power to Gas (PtG) as an energy storage is a novel technology that is considered to be a viable solution for the curtailed off-peak surplus power generated from intermittent renewable energy sources, particularly wind and solar. The existing natural gas distribution system is utilized to store and to distribute hydrogen produced via electrolysis with and without the consideration of additional hydrogen storage considering two recovery pathways, which are power-to-gas-to-power (PtGtP) and power-to-gas-to end users (PtGtU) to satisfy power and end-users demands. The potential energy hub system is modeled using a multiobjective and multiperiod mixed integer linear programming model that minimizes the cost of energy production and storage, environmental and health impact costs of emissions, and power losses from renewable intermittent energy sources. The proposed model is designed to evaluate the optimal operation and sizing of the energy producers and the energy storage system, as well as the interactions between them. The model is applied to a case study based on a simulated community in southern Ontario in order to illustrate its feasibility and applicability.