ABSTRACT
Renewable energy has been the sole basis of human endeavour until quite recently. This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book attempts to map the energy use of Neanderthals during the benign interglacial period 125,000 years ago, primarily for space heating and food cooking. It uses a needs classification in the context of contemporarily widespread neoclassical liberal economic thinking to discuss efficiency measures. The book establishes a convenient measure of efficiency applicable across vehicle types and sizes. Some of the remaining renewable energy types have a history as long as that of solar and wind energy. This is true for hydro energy, which was used in classical societies such as Roman society, where the construction of long aqueducts and sewage systems bear witness to advanced knowledge of hydrological technology. Variations in winds play an important role in applications such as covering electricity demand.
