Sustainable energy is a numbers game with many zeroes. Many experiments are possible in a laboratory, or as a small pilot, but to make a difference, these technologies needs to be scaled up many orders of magnitude.
Breathingearth.net gives a sense of these dimensions through an interactive map showing how much time it takes for various nations to emit a 1000 tonnes of CO2. Your visit to the site will also be measured in terms of global CO2 emissions.
Another site measures time in terms of barrels of oil. Chevron's Will you join us campaign. During the time of writing this simple post, the world consumed a million barrels of oil, and a few 100,000 tonnes of CO2 have been emitted.