There is increasing consensus in both the scientific and political communities that significant reductions in greenhouse gas (GHG) emissions are necessary to limit the magnitude and extent of climate change. Renewable energy systems already reduce GHG emissions from the energy sector, although on a modest scale. Most long-term energy projections show that renewable energy will play a major role in the global energy supply in the second half of the century, with capacity increasing gradually in the first three decades. On the other hand, Turkey is heavily dependent on expensive imported energy resources (oil, gas and coal) that place a big burden on the economy and air pollution is becoming a great environmental concern in the country. In this regard, renewable energy resources appear to be one of the most efficient and effective solutions for clean and sustainable energy development in Turkey. Turkey's geographical location has several advantages for extensive use of most of these renewable energy sources. This article presents a review of the potential and utilization of the fossil fuels and the renewable energy sources in the world and in Turkey.