No doubt Diesels have economies of scale on their side. Many people even seem prefer a Diesel to a hybrid due to the fact the system is less complicated and it's tried and true technology, but just as you said, running our cars on biodiesel and ethanol to conserve are only a stop-gap.
Many expect Hydrogen Fuel to be the next clean and secure energy source of the Future .
I do not see this happening anytime soon because Hydrogen is four times as expensive to produce as gasoline and Hydrogen storage systems are now inadequate for use in the wide range of vehicles that consumers demand. Certainly new technology is needed and it's development will take some time.
Coming on the sooner side, before we can expect to see cars fueled by hydrogen, my eye is drawn to the many countries that are looking to the natural elements as a source of energy and electicity. I view Wind to be the fastest growing source of electricity in the world. As the country's fast economic development demands more electricity, and the world moves towards renewable resources, it is China who is looking at wind as an energy source.
China is now taking measures to promote commercial development of wind energy use and to encourage the establishment of wind electricity plants. Germany and the United States are also attempting to install thousands of megawatts of wind power as well. Favorable incentive policies for wind power development from the US government is up and coming.
Extra terrestrials will not help us as we grapple with this fuel crisis. In the future, they will help us in finding the answers about how to survive in a changing world. Extra terrestrials will teach us how to utilize our environment to the fullest and tap into the natural resources we will need without destroying eco-systems.