>If for example a cheap, simple new technology would be out by tomorrow, that provides allmost unlimited energy (let's say a wonderful simple approach to cold fusion◇) - then all the dirty stuff we do today, because it is cheap - could be done without the dirt of fossil fuels.

To paraphrase something that I remember reading once but now cannot find because Google cannot ever help you find anything useful (nor can the others but at least you aren't giving them all your privacy for nothing):

The person who creates a new and abundant source of energy without at the same time creating an equivalent heat sink for this planet would be history's greatest monster.