A Cornell-led collaboration has successfully developed a 10cm by 10cm prototype device that produces carbon-free 'green' hydrogen from seawater through solar-powered electrolysis. This innovative approach not only generates green hydrogen but also provides potable water as a byproduct, addressing key challenges in sustainable technology. The hybrid solar distillation-water electrolysis (HSD-WE) device currently achieves an energy efficiency of 12.6% and produces 200 milliliters of hydrogen per hour directly from seawater under natural sunlight. With the aim of reducing the cost of green hydrogen production to $1 per kilogram within 15 years, this technology has the potential to contribute significantly to achieving net-zero emissions by 2050. The technology leverages the vast resources of solar energy and seawater, both abundant and free resources, to overcome the high cost associated with conventional green hydrogen production methods. By efficiently utilizing the waste heat from photovoltaics, the device can evaporate seawater, leaving salt behind and condensing desalinated vapor into clean water. This clean water can further be used for drinking, creating a dual benefit of producing hydrogen and providing potable water. The integrated design of the device, which combines desalination, electrolysis, and solar energy conversion, showcases a novel approach to sustainability technology. The team envisions incorporating this technology into solar farms to enhance the efficiency and lifespan of PV panels while producing green hydrogen. By significantly lowering the cost of green hydrogen production, this innovative device opens up possibilities for large-scale adoption, driven by the dual goals of reducing carbon emissions and ensuring cost-effectiveness. The research, published in Energy & Environmental Science, marks a significant advancement in the field of renewable energy and sustainable technology, offering a promising solution to the intertwined challenges of energy production and water scarcity.