The study compared electricity generation systems using the life cycle carbon emission among the studied Kenyan, Rwandan and Tanzanian grids. The article presents the possible grid electricity generation mixes and purchase which can offer the lowest grid carbon emission. The developed inventory workbooks were adopted to account for residue carbon emissions related to the capacity survival lifetime, retired generation capacity, recycling rate and the current power trade planned in the study area. The current installed and operated grid electricity generation systems-process revealed to be a dominant emission factor in the studied grids. The study revealed the carbon reduction potential from the current grid-carbon emission upon the adoption of 100% renewable grid electricity generation mixes in the study area. The specific monitoring of the electricity generation capacity survival and retirement rates recommended for the future electrical science-policy research.