Tesla's Solar Power Storage Unit - Businessweek

More SolarCity + Tesla details

"At the most basic level, SolarCity looks like a solar panel installer. If, however, you dig a bit deeper, the company acts a lot more like a utility. It’s the leader in solar installations and has created a network of capacity that now is complemented by these storage systems.
The energy companies have taken notice of SolarCity’s growing ambitions. The company has been dragged into fights over the rebates people receive in some states for going solar. And politicians such as Jeff Sessions, the junior Republican senator from Alabama, have started offensives against the company, which will leave you shocked by this last sentence. Southern Co. (SO), a utility, is Session’s largest donor."

Tesla's Solar Power Storage Unit - Businessweek