Musk, the CEO of Tesla and chairman of SolarCity, made the announcement on Twitter, noting the combined company would unveil the solar roof with integrated battery and Tesla charger on Oct. 28 in San Francisco.
Musk originally announced plans for SolarCity's new building-integrated solar panels in early August. It wasn't clear just what he had in mind, except that the new product will not look like conventional solar panels, which are installed on racks attached to the roof.
Without being more specific, he said in August the new product would not be a "thing on the roof. It is the roof."
Other manufacturers have produced roof singles that double as solar collectors. The modules are not as efficient as conventional solar panels, and they're more expensive. Dow Chemical, which made such a product called "Powerhouse," dropped the brand earlier this year less than five years after entering the market.
One key difference in the SolarCity solar collector, whatever its specifics, would be the integration of the Tesla Powerwall battery. It's capable of storing electricity produced at peak times of the day for use later.