The bigger and engine is, the more efficient it typically is. Electric cars are already more clean even when you factor in the filthiest of power plants.
Anyways, electric cars are made for renewables (sans hydro) and nuclear that provide energy when it might not be needed but can be used for charging batteries instead. Gas will fill in the gaps, but it's on demand nature means it doesn't really become more useful like the other sources do with car electrification.
Of course, if somebody in the Western world can figure out how to build a nuclear reactor on time with a competitive budget, nuclear may enter that mix of new construction. But right now, with the past decades' trends, it is not looking good for nuclear.
LNG is a big electricity creation fuel, escaping methane is the big pollution challenge.
With the push for less nuclear, and less coal, all that's left is oil and natural gas. Renewable energy is no where near where it's necessary. So invest in companies that build windmills, solar, etc. But also natural gaz power plants.
Really the best investments are construction companies, and companies that manage and build the power grid infrastructure.