PRINCETON, N.J.--(BUSINESS WIRE)--NRG Energy, Inc. (NYSE:NRG) has acquired Pure Energies Group, Inc. (Pure Energies), a residential solar industry leader in the critical area of web-based customer acquisition. Pure Energies completes the residential solar capabilities NRG has been working to assemble and perfectly complements NRG's acquisition earlier this year of Roof Diagnostics Solar, a leader in home solar direct sales and installation, and NRG's own Residential Solar Solutions, which has f