batteries
Several posts comment that we'll run out of resources to build batteries. This thinking assumes that the components are limited and non-reusable like petroleum. The batteries use metals like lithium, nickel, iron, manganese and carbon.
1. All of these elements are available in large amounts. The so called problems with future lithium supply shortages are based on supplies of lithium salts that can, literally, be scrapped off the ground. Known readily accessible reserves are 30 million tons or so. However, it's a common enough element found in many minerals which could be exploited once these resources are used up. Technically, there is 230 billion tons of the stuff disolved in seawater; although, technically, it would be difficult to extract.
2. The batteries can be recycled. So, at the end of the batteries life, the metals can be put back into the resource pool.