Oil is used in a number of places for electricity production. Specifically, it is widely used inside oil exporting nations, thus limiting the amount that they can sell to outside customers.

Natural gas is also a widely used source of fuel in power plants that has a great deal of potential as a clean burning vehicle fuel. See, for example Natural Gas Can Power Vehicles OR Electric Power Plants

Nuclear power also has a 50 year record of applicability as a ship propulsion source, directly replacing oil in that application.

My final suggestion right now is to use nuclear power as a process heat source for enhanced recovery of fuels like the tar sands in Alberta and for synthetic fuel production using coal and water to create liquid hydrocarbons.

None of those by itself will solve the problem, but together they can make a significant impact on the balance between liquid fuel supply and liquid fuel demand.