Non-renewable technologies still play a significant role in the electricity generation mix of most countries. Thus, relevant up-to-date environmental data are needed to provide a good understanding of the environmental consequences of the fossil fuel electricity generation technologies. The focus of this work is to examine the fossil based electricity generation technologies used in Ecuador, providing a compelling insight into the revision of existent international databases. The main combinations of fossil fuel and thermal generation technologies have been studied: fuel oil in steam power plants (FO-SP), fuel oil in internal combustion engine power plants (FO-ICE), natural gas in gas turbine power plants (NG-GT), and diesel in gas turbine power plants (D-GT). ISO standards and CML 2000 methodology were further considered to quantify the potential environmental impact associated with the systems. Results show that NG-GT has the lowest environmental burdens, while FO-SP represents the highest impacts in 5 of the 6 studied impact categories. It is remarkable that for the same type of fuel (fuel oil), the ICE power plants have a lower environmental impact than FO-SP plants. Finally, lights and shadows of fossil-based electricity are discussed to provide a general picture of the current debate concerning transition pathways.