Complex sentence: The Swedish utility Vattenfall did a study of full life cycle emissions of Nuclear, Hydro, Coal, Gas, Solar Cell, Peat and Wind, which concluded that nuclear power produced the smallest amount of CO 2 of any of their electricity sources.
Split into simpler sentences: The Swedish utility Vattenfall did a study of full life cycle emissions of Nuclear, Hydro, Coal, Gas, Solar Cell, Peat and Wind which the utility uses to produce electricity. The study also concluded that nuclear power produced the smallest amount of CO 2 of any of their electricity sources.