“Since 2007, more than half of humanity has lived in urban areas, and by 2050 more than 6.3 billion people will live in cities, accounting for two-thirds of the global population, with a rising share in megacities of more than 10 million people. Most of those people will live in high-rises, so there will be only a limited possibility of local electric power generation, but they’ll need an unceasing supply of electricity to power their homes, services, industries, and transportation.”

—- Professor Vaclav Smil, Grid Electricity Storage: Size Matters