Useful energy and the climate

This chapter characterizes modern energy systems at the scale of individual firms and households, highlighting the interdependencies between their choices and those of state-owned and private firms that supply energy. It shows that energy is demanded for the useful services and materials that it enables. These benefits from energy flow through the energy-using equipment and appliances in buildings, transport vehicles, and industrial processes for making useful materials like steel, cement, plastics and chemicals. The demand for energy is thus derived from the demand for other things. To transform energy systems, while maintaining living standards that benefit from current energy use and creating opportunities for sustainable growth, it is necessary to change technologies in much of the energy-using and -producing capital stock, including those for producing electric power and fuels. The chapter also explains why current technologies that use fossil fuels can disrupt the Earth's carbon cycle and change its climate.