Cheaper electric cars may help oil firms to green their businesses faster

Batteries are expected to only make up only 15% of a vehicle's total costs by 2030, compared with 30% today.

A decade ago, some of the smartest minds at the US Department of Energy set an ambitious goal: lower the cost of battery packs to $100 per kilowatt-hour from more than $1000 per kWh. If achieved, electric cars would reach cost parity with internal-combustion engine cars — unleashing a revolution. 

That moment is here. Later today, at Tesla’s Battery Day event, Elon Musk could announce that the California-based company now makes batteries that cost less than $100 per kWh. Even if he doesn’t, the goal is within reach. In March, General Motors, partnering with South Korean battery maker LG Chem,