There are plenty of great ways to generate lots of clean power, many of which are in use. Don't make the mistaken assumption that all electricity is generated via fossil fuel.
I'm not sure why we've not gone largely nuclear yet, for example. This ain't the 50's; reactors are safe, we can dispose of the waste effectively, and overall it's far more efficient for generating large amounts of power safely. There are also some really neat new hydrogen plants that can refine hydrogen from water via hydrolysis. You could then use this hydrogen as a fuel itself or burn it for electricity. Either way it's very clean and very efficient.
And you and I both know the U.S military doesn't use electric engines in its vehicles because the technology to effectively power them simply does not exist. Tesla's aren't tanks. Tanks need absurd amounts of power to both simply move the massive vehicle and power an ever growing suite of onboard systems. Aircraft are even more demanding in these regards. They'll go electric one day, but most definitely not today.