Tesla is hardly the only player in the nascent electric truck market — as Bloomberg notes — as big companies like Daimler and Cummins are moving toward commercialization.

Why electric trucks matter: Trucks, especially big rigs, are a small percentage of vehicles on the road but use lots of oil. (Check out the chart below, reconstructed from the International Energy Agency's new World Energy Outlook 2017.)

Data: IEA World Energy Outlook 2017, OECD/IEA; Chart: Andrew Witherspoon / Axios

In what amounts to IEA's base case (a model of existing and officially announced policies), oil demand for trucking swells to 20 million barrels per day in 2040, led by that sharp increase you see in diesel demand for heavy-duty freight.

• It's one reason, though hardly the only one, why IEA does not forecast a peak in global crude oil demand through the end of their analysis period in 2040.

The bottom line: Widespread deployment of electric heavy-duty trucking — alongside other alternative fuels and stronger fuel efficiency mandates for diesel-powered rigs — could alter the trajectory of oil demand in coming decade if Musk and other players can make it cost-effective.

Go deeper: Check out a preview of Tesla's electric truck, which is scheduled to be unveiled today.