Energy saving comprises a set of behaviours, methods and interventions that allow for the reduction of consumption of energy that is needed to carry out different activities. A top priority for sustainable development should be a lower consumption of energy from fossil fuels (such as coal, natural gas, oil). Energy saving can also be achieved through the purchase of low consumption machinery and household appliances (class A energy efficiency), as well as interventions aimed at reducing energy dispersion. Energy saving goes hand in hand with the production of energy from renewable resources: clean energy.