ENERGY AND TECHNOLOGY Energy is the ability a physical system has to do work on other physical system always equivalent to the ability to exert pulls or pushes against the basic forces of nature along a path of a certain length. Energy cannot be created or destroyed and is identified with its mass. Energy is a scalar physical quantity. In the international system of units, energy is measured in joules, but there are other units like kilowatt-hours and kilocalories. Energy can be transferred from one system to the other by transferring matter through it, since matter is equivalent to energy. When energy is transferred by means of other than matter-transfer, the transfer produces changes to the second system as a result of work done on it. For example a system can emit energy to another by transferring electromagnetic energy (radiation) where by it creates forces upon the particles that absorb the radiation. A system may transfer energy to another by physically impacting it but in this case the energy of motion in an object called kinetic energy, results in forces acting over the distances to appear in another object that is struck. Thermal energy by heat can be transferred by electromagnetic radiation, or by physical contact in which direct particle-particle impacts transfer kinetic energy. Potential energy is the energy that is stored by force-fields and particles that have been forced into a new physical configuration in the field by doing work on them. Sustainable energy is the provision of energy that meets the needs of the present without compromising the ability of the future generations to meet their needs. Meaning the usage of such energy can potentially be kept up well into the future without causing harmful consequences for future generation. There are a number of types of energy can be thought of as sustainable and many governments promote the use of sustainable energy and the development of new types of energy generating technology which fit within this model. Sustainable energy includes all renewable energy sources such as geothermal energy, bio-energy, hydroelectricity, solar energy, wind energy, wave power, and tidal power. It also includes technologies that improve energy efficiency. Sustainable energy is also distinct from low carbon energy which is only sustainable only in the sense that it does not add the carbon dioxide in the atmosphere. Wind energy is sustainable in the fact that it has zero fuel risk and also low operational and maintenance costs. It also provide total protection and zero risk from carbon costs, no risk in geo-politic associated with supply infrastructure constraints or political dependence on other countries. It is also permanently available in massive. Geothermal energy is considered sustainable because the heat extraction is small compared with the Earth’s heat content. Technologies in use include dry steam power plants, flash steam power plants and binary cycle power plants. For example long sustainability of geothermal energy demonstrated at the Lardarello field in Italy. There are several factors that go into making energy sustainable. The first is whether or not the current use of the energy is something which could potentially persist into the future which leads many forms of renewable energy to qualify as sustainable. For example, people can generate energy from windmills, waves, and the sun without running out of energy and resources, making these methods sustainable for use by future generations. Since earth’s supply of crude oil will peter out, fossil fuels are not considered as sustainable. Renewable energy involves the creation, harnessing and implementation of sustainable resources. This mean that the source from which the energy is cultivated can be replenished and reused over and over again. Renewable energy is friendly in the environment since there are no damages it brings to the atmosphere. Renewable energy projects are also suited to rural and remote areas, where energy is often crucial in human development. Wind power is renewable since airflows can be used to run turbines and this power is permanent and readily available in the nature. Wind is created primarily by temperature differences among the sea, land, and air, and the overall temperature gradient that exist from the equator to the poles. Wind has power that rotates the turbines and finally produces energy. Wave energy is renewable in the sense that waves are readily available in the oceans and seas. Peak power is generally available in the deep water waves from open-sea swells produced from long fetches of prevailing wind that finally produce energy. Wave energy is more advantageous in the sense that it has energy fluxes available and the predictability of wave conditions over periods of days. Waves are created by wind which makes them to transmit energy over long distances. For example in UK wave resources is quite significant since they could generate possibly 50% of its electricity. Hydro-power is also renewable since is generated from shaft power from falling water. The power is then used for direct mechanical purposes or more frequently for generating electricity. This power is by far the most established and widely used renewable resource for electricity generation and commercial investment. Gravitational potential energy is stored in the water above a waterfall or a dam. Because of the greater height of the water, it will arrive at the turbines at high pressure where a great deal of energy is extracted. For example mountainous countries like Switzerland and New Zealand, hydro-electric power provides more than half of the country’s energy need. Solar energy is renewable in the sense that is a natural resource and can be used continuous. Solar energy is the most available resource, and over the millenniums from the ancient societies to present societies, human civilization has effectively used the natural, uncondensed and unrefined solar radiation energy to produce light and heat and to grow crops. Technology has improved the capability of sunlight where it is tapped and then enhanced to release guided voltage and this energy is utilized for other applications which could be domestic or industrial. These could be producing electricity as well as steam and hot water for industrial processes. Sunlight must be brought on to a focus into a small area, similar to that of a lens, to permit the accumulation of intense heat which in turn can be changed into electricity in a modernized heat conversion system like engine or battery. Conclusion There are various advantages of renewing and sustaining energy. The greatest advantage of renewing energy is the fact that it’s clean green form of power and produces minimal carbon footprint. Due to this advantage individuals are getting on the renewable system and choosing to utilize green energy sources such as solar power, wind power and geothermal generation. Global warming being a major drive to current decisions on the kind of energy families and factories ought to choose but availability takes into consideration cost and present appliances of extraction. Setting up the above green energy sources require hefty initial costs; existing authorities can implement policies to make them available and affordable to encourage people to utilize them. In solar energy, sun will be always be there, and in abundance; the amount of solar energy intercepted by the earth every minute is greater than the amount of energy the world uses in fossil fuels each year. The existence of wind as a source has never been threatened; the energy in the winds that blow across the earth’s surface annually can produce more than 16 billion GJ of electricity. Also to the unexploited tide energy; the moon that causes these tides will always be there. Like wise to the hydro electric power water is always readily available. References Kaplan,W,1985.Energy Sustainability :The Case Of Photovoltaics, Oberlin college publishing Twidell,J,Weir,D 2006.Renewable Energy Resouces,Taylor and Francis publishing Kelly,A 2007.Energy supply and renewable resouces.Infobase publishing