In the second half of the 21^st century, the demand of energy will increase considerably, as a consequence of the world population growth, the increasing access to electricity in the developing countries and the tendency to increase the urban population with respect to the countryside. Fossil fuels, as petroleum, coal and natural gas, on which the 19^th and 20^th century economies and civilization mainly relied on, are responsible of greenhouse gases and pollution. Fusion energy can help meet a significant amount of global electricity demand: it represents an opportunity to produce large quantities of electricity with low fuel consumption and, above all, without greenhouse gas emissions.