It can and is. Building the infrastructure for wind, solar, tide, etc. power production is a massive x massive x massive undertaking. Let alone the power grid able to carry that much more energy. But electric energy for portable devices (cars, planes, trains, boats, Rush Limbaugh's mouth) is no small problem. Current battery technology is woefully insufficient. Nothing carries as much energy in as small a space as coal or petroleum-based fuels. And battery production at this point is very dirty. What is needed is a paradigm shift in energy storage. None seems on the horizon.

Our great-grandchildren, after we run out of petroleum, will marvel at pictures of airplanes and wonder how they ever were able to fly through the sky, and not believe it really happened. Like people are starting to doubt the moon landing. Only with better cause.