Increasing production of renewable energy is helping to make energy supplies greener. However, a growing challenge is balancing the demand from users of the electricity grid with naturally unpredictable supplies of renewable energy from sources such as solar and wind. By buying electricity when demand is low and production from solar and wind is high, Shell is helping to balance the electricity grid. This excess energy can then be used to produce green hydrogen from water in a process called electrolysis. The hydrogen is then compressed and supplied as fuel for quiet hydrogen fuel-cell vehicles which only emit clean water vapour as they are driven. Hydrogen may also be used to power fuel cells which can supply electricity and heat for homes and businesses.