This article presents a comparison between geothermal energy and other energy sources in Turkey. Turkey's primary energy consumption is about 64 Mtoe in 2003, mostly provided by fossil fuels (74.7%). Renewables collectively provide 25.3% of the primary energy, in the form of hydro (14.6%), combustible renewable and waste (9%), geothermal (1.2%), and the other renewables (0.5%). Although Turkey has a great geothermal potential (Turkey is the seventh richest country in the world in geothermal energy potential), it uses only about 4% of this potential efficiently. Present applications have shown that geothermal energy is clean and much cheaper compared to the other fossil fuels and other renewable energy sources for Turkey. Therefore, it is a promising alternative and development studies and investments in this sector should be supported. (C) 2006 Elsevier Ltd. All rights reserved.