Hazards assessment and technical actions due to the production of pressured hydrogen within a pilot photovoltaic-electrolyzer-fuel cell power system for agricultural equipment

A pilot power system formed by photovoltaic panels, alkaline electrolyzer and fuel cell stacks was designed and set up to supply the heating system of an experimental greenhouse. The aim of this paper is to analyze the main safety aspects of this power system connected to the management of the pressured hydrogen, such as the explosion limits of the mixture hydrogen-oxygen, the extension of the danger zone, the protection pressure vessels and the system to make unreactive the plant. The electrolyzer unit is the core of this plant and from the safety point of view has been equipped with devices able to highlight the malfunctions before they cause damages. Alarm situations are highlighted and the production process is cut off in safe conditions in the event that the operational parameters have an abnormal deviation from the design values. Also the entire power system has been designed so that any failure to its components does not compromise the workers’ safety even if the risk analysis is in progress because technical operations are being carried out for enhancing the plant functionality, making it more suitable to the designed task of supplying electrically the greenhouse heating system during cold periods. Some experimental data pertinent to the solar radiation and the corresponding hydrogen production rate are also reported. At present it does not exist a well-established safety reference protocol to design the reliability of these types of power plants and then the assumed safety measures even if related to the achieved pilot installation, can represent an original base of reference to set up guidelines for designing the safety of power plants in the future available for agricultural purposes.