During this century the human race will have to address the challenge of deeply transforming the world energy system to make it much more sustain- able and environmentally friendly than the one we currently have. To achieve this, it will have to substantially increase the market penetration of all types of renewable energy technologies, and especially of solar technolo- gies, since these technologies will be called upon to be the main pillars of the new world energy system, because of the vast quantities and the high quality of the solar energy reaching the Earth at every instant
