A primer on the transition to low-carbon energy and its effect on economic performance. The widespread use of fossil fuel has transformed productivity over the last 150 years, bringing prosperity to billions. But now there is a problem. The vast flow of cheap fossil fuel energy that currently powers over three-quarters of the global economy is no longer sustainable. Low-cost reserves are being depleted, and there are mounting concerns about the cumulative effect of fossil fuel emissions on the environment. As a result, this vital source of power will have to be substantially replaced over the next few decades. What happens when you replace such a productive energy platform? This book investigates the likely economic consequences, taking into consideration the scale of the task, the productivity of low-carbon substitutes and the disruption of fossil fuel energy. It highlights the cost and displacement pressures involved, but also shows how these will be offset to some degree by ongoing improvements in the overall efficiency of energy conversion. Finally, it charts the likely course of this transition and its effect on economic performance over time, taking into account the dynamic interactions between suppliers, consumers, policymakers and investors; as well as the role of factors such as scale, network effects, know-how and technology.