And remember the most important rule...
You don't have to replace fossil fuels through a whole industry to be a success.
Every car that burns biofuels is one that doesn't need oil from the ground. Every solar panel is a little bit less power a power plant has to generate. It adds up, and starts really adding up as it becomes economical.
Right now, it's being forecast that in a few years, more phone minutes will be on cell phones than land lines in the U.S.
Twenty years ago, who saw that coming? It's possible that in ten or fifteen years you might look around and say, "hey, when did all the houses get solar panel roofs?"