“Before embarking on ‘net zero’ for a billion people, how about trying it out in a place with, say, 10,000, or 50,000, or 100,000 people – see if it can actually work and how much it will cost?” Menton wrote. In other words, he explained, take a small city and power its electricity grid entirely on wind, solar and energy storage for a full year without any kind of baseload backup from fossil fuels.