SUMMARY
Energy is the measure of the development of any nation. Booming economic growth, rapid industrialization and high standard of living of the global population demand more and more energy in different forms. Since the quantity of available energy from conventional resources is depleting day by day, development of newer or renewable energy technologies and improvement of conventional technologies become necessary to meet the energy demand in the future. The world is undergoing a period of global climate change. Growing demand for energy despite limited fossil fuel reserves and growing environmental concerns due to increased emissions of carbon dioxide and methane, well-known green house gases, is undoubtedly the major challenge of the 21st century. It is of international importance that technological solutions can be brought to bear to solve these problems as well as providing alternative sources of power and energy. To achieve a sustainable development, the origin and the use of energy have to be addressed, and advanced energy technologies for both fossil and renewable energy carriers have to be developed. There is need to think globally but act locally. The adoption of new energy sources, energy carriers and better energy management will not only affect the energy market but will also have social economic and environmental impacts. New energy technologies and particular heating and cooling technologies are decentralized and will create markets and employment essentially at a local level and, therefore, will induce a modification of individual behavior. From an economic viewpoint, new energy technologies are capital intensive sources of energy and the present period is particularly interested in the development of such technologies and systems due to relatively low cost of money and high cost of energy. The scientific community has not only to think and develop advanced energy technologies but also to contribute in improving the existing ones. Even if renewable energies and new energy carriers, such as hydrogen, are promising solutions, our society still relies on fossil fuels as primary energy for many applications.