Techno-ökonomische Optimierung von energetischen und stofflichen Speichern zur Offshore-Produktion von PtX-Produkten

Abstract

The excessive use of fossil fuels as a source of energy has increased the levels of carbon dioxide (CO₂) and other greenhouse gases (GHG) in the Earth's atmosphere, resulting in accelerating global warming. In response to these environmental challenges, renewable energy sources (RES) are becoming increasingly popular across various sectors. However, further changes are still needed, particularly in the chemical industry, transportation, shipping, and aviation. One promising application area with untapped resources is offshore or isolated sites, where the potential for wind energy is significantly higher and could be further expanded. But, energy transportation from offshore to land is seen as a crucial challenge for such locations. The potential solutions might be the use of chemical energy carriers and produced via Power-to-X (PtX) technologies. PtX plants require optimization to operate in the steady-state condition while providing additional storage system. This master's study investigates the techno-economic optimization of material storage solutions for offshore hydrogen production of PtX products. A continuous hydrogen supply is essential for PtX products to maintain stable chemical production and provide constant flow to the downstream plant for better utilization of the equipment. This stability is particularly important when utilizing the fluctuating power of offshore wind energy. For the offshore PtX plants, current research focuses on identifying and evaluating optimal storage capacity that can support the continuous and efficient operation of hydrogen production for offshore PtX processes. The research explores the integration of offshore platforms with hydrogen storage tanks, aiming to ensure an uninterrupted hydrogen flow and minimize supply disruptions to the chemical processing plant. The system is optimized to minimize the Levelized Cost of Hydrogen (LCOH) through the application of linear programming techniques and integration of the platform cost method in python model. This thesis is extension of the python model which was developed by Raab et. al. [7], and provides optimization for offshore hydrogen plants. Additionally, alternative options, for instance, change in wind turbine, transmission of offshore wind energy to onshore hydrogen plants using export cables apart from the optimization model, are examined to assess the cost-effectiveness. This study provides insights into the most suitable offshore or onshore hydrogen production case for facilitating a sustainable hydrogen flow for the PtX plants. Results indicates that, considering system downtime shows that controlled interruptions can reduce component sizing and improve economic viability for island applications. In this case, 760 hours of downtime resulted in an optimized hydrogen production rate of 9.07 €/kg.