Sustainable Futures explores the current threats to our world resources and the possible solutions to some of the most urgent and difficult problems facing today's decision-makers. What is a renewable energy source? Is nuclear power a good source of energy? Why are wind farms so controversial? And, how is energy linked to climate change? "Energy" answers these questions and many others. From turning off lights to hydroelectric schemes, "Energy" looks at issues surrounding the world's energy supplies and the demand for energy. Discover what we mean by a sustainable energy source, and what you can do to help conserve energy.