Hydrogen is currently undergoing a renaissance, emerging as a potential key option in the global transition to sustainable energy systems, particularly for decarbonising hard-to-electrify sectors. Hydrogen electrolysis has rapidly reduced costs over the last decade, making large-scale hydrogen production more feasible. However, achieving cost competitiveness with conventional energy sources remains a challenge. This chapter investigates the current capital costs of electrolysers, focusing on the impact of technology, manufacturing scale, and regional production differences. Electrolyser costs vary widely, from $200 to $2,500 per kW, depending on the technology and production scale. Further cost reductions are achievable through manufacturing scale-up, technological improvements, and shifting production to regions with lower costs, such as China. The scale and pace of these potential future cost reductions for hydrogen production will determine whether hydrogen becomes a significant component of the coming low-carbon energy economy.