Tesla bought SolarCity http://www.theverge.com/2016/11/21/13698314/tesla-completes-... - even if they totally flump on cars they still have solar installations, gigafactory (developments), charging stations they could lease and tech/patents they could sell to other EV manufacturers.
Sorry, Tesla bought struggling Solar City as it needed a complete residential energy storage solution to leverage rebates from energy companies. I.e. the sum of the parts is greater than the whole in terms of final price to consumer.
SolarCity was/is $4B in debt at the time of the acquisition. If Tesla's car division fails, solar panels is not the cash cow the company is going to fall back on.
SolarCity was/is $4B in debt at the time of the acquisition. If Tesla's car division fails, solar panels is not the cash cow the company is going to fall back on.