Research Paper (undergraduate) from the year 2011 in the subject Engineering - Power Engineering, , language: English, abstract: Throughout history, the use of energy has been central to the functioning and development of human societies and one of the great challenges that humanity will face, in this twenty-first century, is to give everyone on the planet access to safe, clean and sustainable energy supplies (Boyle, et al., 2003). When providing energy-related services to society, significant environmental and social impact can be produced, especially when fossil or nuclear fuels are used, considering their extraction processes, risks and environment effects, namely those related with CO2 emissions that contributes to present climatic changes. As finite resources, fossil fuel reserves cannot accommodate all the energy demand increase. Proved reserves of oil and gas are sufficient for some few decades, while coal reserves can continue to be explored by 1-2 centuries, more, taking into account the relation between actually proved reserves and the actual production rate (Boyle, et al., 2003). New reserves are being found but requiring new technologic advances in the process and more energy spending. Impacts of extracting energy from fossil or nuclear fuels are greater than they need be because of the low efficiency of our current systems for delivering energy, converting it into forms appropriate for specific tasks, and utilizing it in our homes, machinery, appliances and vehicles (Boyle, et al., 2003). Improving the efficiency of these systems is one of the ways to reduce negative impacts satisfying the same needs of final energy reducing primary energy use. Also, replacing fossil fuel by renewable energy sources, even without reduction of final energy demand, will reduce negative impacts. According with IEA (OECD/IEA, 2010), the total energy demand is expected to increase 47% between 2008 and 2035, maintaining actual policies. If new policies are adopted, the total energy demand is expected increase less (36% in the new policies Scenario and 22% in a more ambitious scenario, which requires the concentration of greenhouse gases in the atmosphere to be limited to around 450 parts per million of CO2 equivalent).
