Sizing of hybrid power plants for hydrogen production

Abstract

The global energy system has to undergo a profound transformation to achieve the targets in the Paris Agreement. In this regard, Hydrogen produced from renewable electricity - achieved through an electrolyser - could facilitate the integration of high levels of variable renewable energy (VRE) into the energy system[1]. This green Hydrogen can be a substitute fuel in decarbonisation and transiting to clean energy sources. Hydrogen has a high gravimetric energy density and can be stored in either liquid or gaseous form. It can be burnt to release heat or used in fuel cells to produce electricity, thereby providing a broad spectrum of applications[2]. Grid issues and increased competition to win subsidies are pushing offshore wind developers to search for new business models to stay active in the market. One of the options could be offshore Power-to-Hydrogen, which consists in the production of hydrogen using the electricity from an offshore wind farm. On the other hand, for hydrogen producers, the changing economics of offshore wind power present a highly encouraging business opportunity to utilize wind electricity (specially near-shore curtailed) as a feed-stock for electrolysis[3]. This research has been focused on identifying the key factors and methodology on selecting a specific topology for a Hybrid Power Plant (HPP) consisting of offshore Wind turbines, Electrolyzer, and Hydrogen Storage System (HSS). Centralized and decentralized configurations for installing Hydrogen Production System (HPS) and offshore and onshore HSS has been developed to compare which configuration will provide highest NP V /CAP EX ratio. This thesis demonstrates that hydrogen price, together with hydrogen plant output requirement and NP V /CAP EX, are three main factors to be considered at the same time for selecting the most proper topology. As the result, under the light of these key factors, optimal plant configuration can be chosen based on project specified objective. In general, with hydrogen price of 4 e/kg topologies with grid connection provide higher NP V /CAEX ratio, however, they have poor investment in electrolyser plant and subsequently struggle to generate significant hydrogen output.