I heard that figure about coal being used to generate electricity somewhere, I can't remember where, but it may not be accurate. The important point is that all fossil fuels, whether coal, oil, or natural gas, are polluting and contribute to global warming.
People driving electric vehicles may feel smug and think they're helping forestall global warming, but driving an electric powered vehicle does not help forestall global warming and, in fact, increases it if that electricity is generated using fossil fuel.
Nikola one trucks use hydrogen, and if that hydrogen is derived from plants that use fossil fuels to generate the electrolysis, then that contributes even more to global warming. But the manufacturer of Nikola one says they will use renewable energy sources where possible to split water.
The Nikola one trucks will be available for Leasing at about 6 or $7,000 per month which, of course, includes all the fuel and maybe insurance. Over the lifetime of a vehicle that would come to about 1/2 million dollars.