Regardless of the source, energy is a major factor for development. It is needed for transport, industrial and commercial activities, buildings and infrastructure, water distribution, and food production. Most of these activities take place in or around cities, which are on average responsible for more than 75 per cent of a country's Gross Domestic Product (GDP) and therefore the main engines of global economic growth. To run their activities, cities require an uninterrupted supply of energy. They consume about 75 per cent of global primary energy and emit between 50 and 60 per cent of the world's total greenhouse gases. Future cities will prioritize energy, resource, and environmental economics through sustainable practices like renewable energy integration, improved energy efficiency, and smart resource management to combat challenges like pollution and increased demand from urbanization. This shift involves a combination of new technologies, urban planning, economic policies, and citizen participation to create more resilient and productive urban environments. This book will equip students with the tools necessary for economic analysis and quantification of impacts of energy systems. It will review the availability of energy resources and study methods for quantification of resource depletion and scarcity. The book will cover basic concepts in economics and their application to energy systems. Tools and techniques for project economics for an individual/company perspective and macro-decision making for society will be introduced. It will discuss basic concepts of welfare economics and environmental economics that are necessary for energy systems analysis and their environmental impacts. The author discusses in detail the new tools that enable the development of better smart cities, such as big data, digital twins, artificial intelligence, and machine learning, which will enable the exploration of scenarios of development much more efficiently than in the past.