(Invited) Development of a Hydrogen Energy System as a Grid Frequency Management Tool

Abstract

In Hawaii, very high penetration levels of intermittent renewable energy sources such as wind and solar are causing challenges in regulation of grid frequency, and as the percentage of these intermittent resources increases can result in their curtailment. It has been postulated that, similar to a battery, the optimized use of an electrolyzer as a variable load may help regulate grid frequency and increase the penetration of renewable energy resources on the grid. The use of an electrolyzer in this way could provide an “ancillary service” to the grid that can be assigned a monetary value. This monetary value can be used to offset the cost of hydrogen production. The hydrogen in turn can be used in high value applications such as a transportation fuel. The Hawai‘i Natural Energy Institute (HNEI) is conducting research to assess the technical potential and economic value of using an electrolyzer-based hydrogen production and storage system as a demand response tool for grid management. A 65 kg/day hydrogen energy system (H2ES) consisting of a PEM electrolyzer, 35 bar buffer tank, 450 bar compressor, and associated chiller systems, has been purchased and installed at the Hawaii Natural Energy Laboratory Hawaii Authority (NELHA) to demonstrate long-term durability of the electrolyzer under cyclic operation required for frequency regulation on an island grid system. A secondary objective is to supply hydrogen for three fuel-cell buses to be operated at Hawai‘i Volcanoes National Park (HAVO) and by the County of Hawai‘i Mass Transit Authority. The hydrogen will be transported from the production site by tube trailers to the HAVO dispensing site. A second dispensing site is located at the NELHA production site. A comprehensive test plan has been developed to characterize the performance and the durability of the electrolyzer under dynamic load conditions and initial testing was conducted at Powertech Labs in Vancouver Canada. A main objective of the test plan is to determine the operating envelope and dynamic limits of the electrolyzer and the overall H2ES. A long-term study shall evaluate the H2ES performance under a load profile developed from a fast acting Battery Energy Storage System (BESS) that is currently in use as a grid management tool on the Big Island grid. These tests shall demonstrate whether the electrolyzer has the capability to effectively mitigate the impacts of intermittent solar and wind power on the grid, while continuously generating 90-80% of its designed hydrogen productioncapacity. The presentation will describe the H2ES configuration, plans for operation in the field, and results of initial tests to determine the dynamic response of the eletrolyzer and overall system