Projects seek to hold electricity for weeks or months Technology remains expensive, may take decades to develop The secret to switching the global energy system entirely to renewables may lay in the universe’s most abundant substance. Hydrogen has drawn backing from big energy companies from Royal Dutch Shell Plc to Uniper SE in addition to carmakers BMW AG and Audi AG . They’re supporting research into how the element can be used to store energy for weeks or even months beyond what lithium-ion batteries can manage. While industry’s investment in hydrogen is small at just $2.5 billion over the last decade, the work offers an answer to the elusive question of how electricity could be kept for use in the future. Batteries increasingly are shifting power from day to night, but they tend to go flat after a few weeks. Hydrogen can be kept indefinitely in tanks. That would […]