Worldwide, power generation from fossil fuels is currently in jeopardy due to carbon dioxide emissions that directly influence the greenhouse effect and thus, climate change. This has led to seek or encourage the use of other sources of power generation, such as hydropower. Small Hydroelectric Plants (SHP) represent a suitable alternative for electric power generation in Colombia due to favorable conditions in its operation and the low environmental impact compared with other available energy sources in the country. SHPs, within the Clean Development Mechanism, are considered a source of clean energy with minimal impacts on the environment. This article presents a review of the existing methodologies for assessing greenhouse gas emissions and the implementation of the ACM0002 methodology in a SHP in Colombia, calculating an updated emission factor in the country.