A Cornell-led collaboration has developed a groundbreaking method to produce carbon-free 'green' hydrogen through solar-powered electrolysis of seawater. The team's hybrid solar distillation-water electrolysis (HSD-WE) device achieves an impressive 12.6% energy efficiency, producing 200 milliliters of hydrogen per hour directly from seawater under natural sunlight. This innovative technology not only generates green hydrogen but also produces potable water as a byproduct, addressing the critical needs for both resources. The technology, reported in Energy & Environmental Science, aims to reduce the cost of green hydrogen production to $1 per kilogram within 15 years, which is a significant advancement towards achieving net-zero emissions by 2050. By utilizing the abundance of solar energy and seawater as infinite and free resources, the device overcomes the high cost associated with traditional green hydrogen production, which relies on deionized water. Through the integration of solar distillation and water electrolysis, the device effectively harnesses waste heat from solar panels to evaporate seawater for desalination. This process is highly efficient, with more than 90% evaporation efficiency. Once the seawater evaporates, clean water is produced, and the remaining vapor is split into hydrogen and oxygen through electrolysis. The team envisions the widespread adoption of this technology, highlighting its potential to not only drive down the cost of green hydrogen but also enhance the efficiency and lifespan of solar panels by incorporating the device into solar farms. With a positive sentiment towards sustainable and renewable energy solutions, the innovative approach of this research demonstrates a promising step towards a greener future.