New energy sources and increased energy efficiency are important for development, and revolutionary advances in technology appear necessary even to maintain today's general standard of living and economic prosperity . The problems ahead of us may seem daunting. For example, it has been stated that the warming and precipitation trends due to antropogenic, energy-related climate changes during the past 30 years already claim over 150,000 human lives annually [2, 3]. These climate changes are also expected to be accompanied by more common and/or extreme events such as heatwaves, heavy rainfall, and storms and coastal flooding; there are also fears that non-linear climate responses will lead to breakdown of ocean ``conveyor belt'' circulation, collapse of major ice sheets, and/or release of large quantities of methane at high latitudes thus intensifying global warming . Adding to the precarious situation, the urgently needed advances in energy related technology must take place for an increasing population, whose growing concentration in mega-cities leads to ``heat islands'' which tend to aggravate the warming  and can increase the urban cooling load by up to 25% compared to the case of surrounding rural areas . By 2050 there will be some ten billion people in the World. Energy must be available to them all, and it has to be clean. New technologies are necessary to accomplish this. Some of these technologies -- mainly related to efficient solar energy utilization and to energy savings in the built environment -- will be discussed in this Chapter.
Granqvist, C. G. (2011). Applications of Transparent Conductors to Solar Energy and Energy Efficiency. In Handbook of Transparent Conductors (pp. 353–423). Springer US. https://doi.org/10.1007/978-1-4419-1638-9_11