Thread drift, I'm afraid, but LH: can you provide examples of these non-polluting vehicles that the oil-companies have suppressed? Are you sure you haven't been talking in the pub to one of those people who's cousin/friend/dentist invented a car that ran on water but who couldn't exploit his invention because of the oil companies (we've all met 'em, but never seen t omeet the cousin/friend/dentist)?

Please remember that electric- and hydrogen-powered vehicles are not non-polluting, they merely move the pollution back to the power-station.

I saw one of these "cars that runs on water" on the web a little while ago. You merely replace the spark-plugs with wave-guides from the magnetron from a domestic microwave-cooker, fill your tank with water and start up. The microwave vapourises the water in the cylinder and turns your gas-powered engine into a steam engine. Now that's so simple, why didn't I think of it? And it violates the first law of thermodynamics, too!