This study investigates the cost of clean hydrogen produced from offshore wind and electrolysis, comparing it to conventional hydrogen production methods. The research presents a novel techno-economic model for offshore electrolysis, which makes hydrogen production fully dispatchable by leveraging geological salt-cavern storage. The model calculates the lifetime costs across system components and the Levelised Cost of Hydrogen (LCOH). Using the United Kingdom as a case study, the LCOH for offshore wind power is calculated as €8.68/kg H₂ using alkaline electrolysis (AEL), €10.49/kg H₂ using proton exchange membrane electrolysis (PEMEL), and €10.88/kg H₂ with grid electricity backup. A stochastic Monte-Carlo model is used to assess cost uncertainty, identifying the cost of capital, electrolyser, and wind farm capital costs, and cost of electricity as the most important drivers of LCOH. Reducing capital costs to current wind farm levels could lower AEL LCOH to €5.32/kg H₂, near competitive with conventional methods. The study also introduces a comprehensive approach to LCOH modeling by combining stochastic and deterministic models, and integrates geological salt-cavern storage for seasonal hydrogen storage. The research highlights the techno-economic feasibility of renewable hydrogen, emphasizing the importance of cost drivers such as capital expenditures, operational expenditures, and the efficiency of electrolysis technologies. The study concludes that AEL is the preferred method for hydrogen production due to its lower cost and higher efficiency, while PEMEL is more expensive. The results show that grid electricity-based electrolysis has a higher LCOH than offshore wind-based electrolysis. The study also discusses the limitations of the model, including the disregard of weather effects and the use of literature-based cost data. Overall, the study provides a detailed analysis of the cost of clean hydrogen production from offshore wind and electrolysis, highlighting the potential for renewable hydrogen to play a significant role in the decarbonisation of the energy system.This study investigates the cost of clean hydrogen produced from offshore wind and electrolysis, comparing it to conventional hydrogen production methods. The research presents a novel techno-economic model for offshore electrolysis, which makes hydrogen production fully dispatchable by leveraging geological salt-cavern storage. The model calculates the lifetime costs across system components and the Levelised Cost of Hydrogen (LCOH). Using the United Kingdom as a case study, the LCOH for offshore wind power is calculated as €8.68/kg H₂ using alkaline electrolysis (AEL), €10.49/kg H₂ using proton exchange membrane electrolysis (PEMEL), and €10.88/kg H₂ with grid electricity backup. A stochastic Monte-Carlo model is used to assess cost uncertainty, identifying the cost of capital, electrolyser, and wind farm capital costs, and cost of electricity as the most important drivers of LCOH. Reducing capital costs to current wind farm levels could lower AEL LCOH to €5.32/kg H₂, near competitive with conventional methods. The study also introduces a comprehensive approach to LCOH modeling by combining stochastic and deterministic models, and integrates geological salt-cavern storage for seasonal hydrogen storage. The research highlights the techno-economic feasibility of renewable hydrogen, emphasizing the importance of cost drivers such as capital expenditures, operational expenditures, and the efficiency of electrolysis technologies. The study concludes that AEL is the preferred method for hydrogen production due to its lower cost and higher efficiency, while PEMEL is more expensive. The results show that grid electricity-based electrolysis has a higher LCOH than offshore wind-based electrolysis. The study also discusses the limitations of the model, including the disregard of weather effects and the use of literature-based cost data. Overall, the study provides a detailed analysis of the cost of clean hydrogen production from offshore wind and electrolysis, highlighting the potential for renewable hydrogen to play a significant role in the decarbonisation of the energy system.