Energy
In physics, energy is the quantitative property that must be transferred to an object in order to perform work on, or to heat, the object. Energy is a conserved quantity; the law of conservation of energy states that energy can be converted in form, but not created or destroyed. The SI unit of energy is the joule, which is the energy transferred to an object by the work of moving it a distance of 1 metre against a force of 1 newton.
Sustainability
Sustainability (from 'sustain' and 'ability') is the process of change, in which the exploitation of resources, the direction of investments, the orientation of technological development and institutional change are all in harmony and enhance both current and future potential to meet human needs and aspirations. The organizing principle for sustainability is sustainable development, which includes the following interconnected domains: environment, economic and social. Sub-domains of sustainable development have been considered also: cultural, technological and political. Sustainable development, is the development that meets the needs of the present without compromising the ability of future generations to meet their own needs. Brundtland Report for the World Commission on Environment and Development (1992) introduced the term of sustainable development.