Every 15 seconds humanity consumes an Olympic swimming pool full of oil. That's 2.5 million liters! The gas and coal deposits are also limited. At the beginning of the 21st century, humans need more energy than ever before. Almost 85 percent of this comes from fossil fuels. By the year 2050 - when the world's population rises to over nine billion - energy demand will double. Can man protect planet Earth, for example with clean, renewable energies?