You could drive yourself crazy calculating all the direct and indirect inputs behind a consumer choice, so here's a handy rule, courtesy of Jerry C.

FORBES: The Guilt-Free Consumer

While it is absolutely essential that we continue to drive down the costs of generating electricity from solar (and wind, which is indirect solar energy, ) doing so alone will not make these renewable energy sources competitive with traditional hydro, fossil or nuclear generated electricity.

FORBES: Storage, Not Generation, is the Challenge to Renewable Energy