Impact of Global Energy Resources Based on Energy Return on their Investment (eroi) Parameters

Human development has been based on the use of the energy resources, especially those of fossil origin (oil, gas, coal, etc.), which are not infinite and damage ecosystems; it is of paramount importance to make a transition to other alternative sources of energy. We compare and discuss many global sources of energy and their impact, based on the useful parameter called energy returned on energy invested or energy return on investment (eroi). In the long run we could expect renewed emphasis on enhanced (stimulated or hot dry rock) geothermal energy sources due to technological advances in deep drilling and the availability of this kind of energy 365 days per year and 24 hours of a day.