I n the fight against climate change, much attention is placed on greening our energy-production methods, which can feel a world away for city dwellers who might never have seen the inside of a power plant. But when we look closer, just around us, we realise that the cities we live in are actually a major driver of energy demand, from the electricity needed to power buildings, to the food trucked in to be cooked in restaurants. With this in mind, in recent years urban planners, start-ups, and governments have been in a race to develop green-tech solutions that can...