Today's global energy market is in the midst of a paradigm shift, from a model dominated by large centralized power plants owned by big utilities to a mixed bag of so-called distributed energy generation facilities — smaller residential, commercial and industrial power generation systems — many of which use renewable resources.

http://www.renewableenergyworld.com/rea/news/article/2013/09/virtual-power-plants-a-new-model-for-renewables-integration