One of the many benefits of green and vegetated roofs is associated with the role they play in either cooling or insulating the buildings they are installed on. The effect they have on the buildings can then effect the energy requirements for heating or cooling that building. The following papers relate to insulating characteristics and energy.
H.F. Castleton, V. Stovin, S.B.M. Beck, and J.B. Davison, 2009, "Green Roofs; Building Energy Savings and the Potential for Retrofit"