PNNL

Abstract

Hydrogen energy storage (HES) transforms and stores electric energy from the grid into hydrogen, and supplements other energy storage and demand response resources in addressing challenges in renewable-intensive power systems. Understanding how to optimally utilize an HES system to maximize its economic benefits from stacked value streams is highly important to their development and deployment. This paper presents a techno-economic assessment framework for an HES system considering three common energy delivery pathways, including 1) bulk sale of hydrogen in the form of transportation fuel and industrial gas, 2) hydrogen and/or synthetic methane injection into the natural gas network, and 3) electricity regeneration locally using a fuel cell or other power conversion devices. In addition, multiple grid and end-user services are considered, such as energy arbitrage, ancillary services, resource adequacy, and critical infrastructure upgrade deferral. Models are developed to capture the operational capability , flexibility, and constraints associated with hydrogen production, compression, storage, and utilization as well as different grid services in an economic assessment. To define the technically achievable benefits, an optimal dispatch formulation is proposed to maximize the economic benefits over a representative year with an hourly time step considering the trade-offs among different value streams. Representative case studies are designed and carried out to show how system configuration, energy delivery pathways, and grid services affect economic benefits. It was found that value streams from bundling grid services are critical for an HES project to be financially viable.