But is this a realistic assumption? It might not be if extracting lithium from the ground becomes increasingly expensive in the same manner that oil is from older fields and other unconventional sources. With dramatically increasing demand for the material, it becomes a real possibility that the price of batteries may never come down. Recycling lithium from depleted batteries is apparently also far more expensive than virgin material. There is of course the possibility of new material breakthroughs that would eliminate the need for lithium. There are also possibilities like silicon nano-wires or ultra capacitors that could dramatically increase energy storage density and reduce the size and requirement for materials like lithium. The only thing we know for sure right now is that we don't know. All this just goes to show the need for pursuing multiple parallel paths for energy diversity, because there doesn't appear that any one solution will be sufficient.