Correlations between component size green hydrogen demand and breakeven price for energy islands

The topic of energy islands is currently a focal point in the push for the energy transition. An ambitious project in the North Sea aims to build an offshore wind-powered electrolyser for green hydrogen production. Power-to-X (PtX) is a process of converting renewable electricity into hydrogen-based energy carriers, such as natural gas, liquid fuels and chemicals. PtH2 represents a subset of PtX, wherein hydrogen is the resultant green energy from the conversion process. Many uncertainties surround PtH2 plants, affecting the economic success of the investment and making the price of hydrogen and the levelized cost of hydrogen (LCOH) of this technology uncompetitive. Several studies have analysed PtH2 layouts to identify the hydrogen price without considering how component capacities and external inputs affect the breakeven price. Unlike previous works, this paper investigates component capacity dependencies under variables such as wind and hydrogen demand shape for dedicated/non-dedicated system layouts. To this end, the techno-economic analysis finds the breakeven price, optimising the components to reach the lowest selling price. Results show that the hydrogen price can reach 2.2 euro/kg for a non-dedicated system for certain combinations of maximum demand and electrolyser capacity. Furthermore, the LCOH analysis revealed that the offshore wind electrolyser system is currently uncompetitive with hydrogen production from carbon-based technologies but is competitive with renewable technologies. The sensitivity analysis reveals the green electricity price in the non-dedicated case for which a dedicated system has a lower optimum hydrogen price. The price limit for the dedicated case is 116 euro/MWh.

Automated summary

The ambitious project in the North Sea aims to build an offshore wind-powered electrolyser for green hydrogen production. However, uncertainties and component capacity dependencies have affected the economic success of PtH2 plants and the competitiveness of hydrogen production technology. Through a techno-economic analysis, this paper determines the lowest selling price by optimizing the components and investigates the impact of variables such as wind and hydrogen demand on system layouts. The results show that the hydrogen price can reach 2.2 euro/kg for certain combinations of maximum demand and electrolyser capacity.