Energy prices are on the rise and international distribution based on the scarcity of natural resources and the environmental impacts are major issues. More and more countries are therefore setting ambitious goals for expanding renewable energies. By the year 2020, the European Union wants to cover 20 percent, China 17 percent, and California even 48 percent of its energy needs through renewable energies. According to todays estimates, more than 500 billion Euros will be invested in the sector worldwide during the same period.