Vertical farming proposals for cities

The idea is simple enough. Imagine a 30-storey building with glass walls, topped off with a huge solar panel. On each floor there would be giant planting beds, indoor fields in effect. There would be a sophisticated irrigation system. And so crops of all kinds and small livestock could all be grown in a controlled environment in the most urban of settings. That means there would be no shipping costs, and no pollution caused by moving produce around the country.