Hydrogen is poised to play a key role in the energy transition by decarbonizing hard-to-electrify sectors and enabling the storage, transport, and trade of renewable energy. Recent forecasts project a thousand-fold expansion of global water electrolysis capacity as early as 2030. In this context, several electrolysis technologies are likely to coexist in the market, each catering to different applications and geographies. They face the common challenge of decreasing the cost of hydrogen produced, for which energy efficiency is a major but not the only factor. In this Perspective, we dispel common misconceptionsrooted in outdated designsaround alkaline water electrolysis and offer an overview of the main technical pathways to reduce the cost of hydrogen from modern systems already under commercialization. By identifying key research needs, we aim to motivate work into overlooked areas that both offer interesting scientific questions and can contribute to the gigawatt-scale production of green hydrogen in the short- to medium-term.