This phenomenon has already occurred. The fuel industry has seen a cost explosion since September 11th. With fossil fuels costing as much as they do people have switched to bio fuels, corn ethanol, or even switched their transportation needs to help deal with the higher cost. In the form of electricity, we will see new energy sources because the cost will increase and people will naturally try and find ways to lower that cost.

The invention/harvesting of other sources has most definitely already begun. This is partially due to increasing energy costs as well as environmental concerns. I think now that sources like solar and wind are becoming more commonplace, the next steps are to make them as affordable, practical and widespread as possible.