Experimental Characterization of an Alkaline Electrolyser and a Compression System for Hydrogen Production and Storage

Abstract

Storing renewable energy in chemicals, like hydrogen, can bring various benefits like high energy density, seasonal storability, possible cost reduction of the final product, and the potential to let renewable power penetrate other markets and to overcome their intermittent availability. In the last year’s production of this gas from renewable energy sources via electrolysis has grown its reputation as one feasible solution to satisfy future zero-emission energy demand. To extend the exploitation of Renewable Energy Source (RES), small-scale conversion plants seem to be an interesting option. In view of a possible widespread adoption of these types of plants, the authors intend to present the experimental characterization of a small-scale hydrogen production and storage plant. The considered experimental plant is based on an alkaline electrolyser and an air-driven hydrogen compression and storage system. The results show that the hydrogen production-specific consumption is, on average, 77 kWh/kgH2. The hydrogen compressor energy requirement is, on average, 15 kWh/kgH2 (data referred to the driving compressed air). The value is higher than data found in literature (4.4–9.3 kWh/kgH2), but the difference can be attributed to the small size of the considered compressor and the choice to limit the compression stages.