Energy from ancient and modern sunshine

The importance of harnessing direct sunshine as a route to providing energy to sustain our modern sophisticated societies, in the not too distant future, is addressed in this chapter. The need to transition away from fossil fuels, because by their combustion in the atmosphere, we are triggering dangerous climate change, is explained in a simple engineering friendly manner, emphasising as it does the thermodynamics and well-established electromagnetic wave propagation principles which underlie the science. That a sustainable, fossil fuel-free future for mankind is entirely possible is also reinforced. The energy in sunshine is garnered naturally by photosynthesis, but this is too inefficient for modern requirements. The range of artificial methods that provide the promise of the collection of very large levels of power from solar rays is broached here, and the various modes identified are examined in detail in later chapters. These come in the form of electricity-generating solar farms ranging from those employing photovoltaic panels located on the ground and in space, to those employing sophisticated optical reflector techniques to gather the incident rays. Optical antennas with their potential for high-efficiency light collection are also considered.