neither of those are true, if they were, remember when tesla wanted to sell trucks like 10 years ago ? if you use electric trucks, half the mass you pay to move around is useless. Also the grid isn't "half coal", the truck doesn't wait for the sun to come out to charge. Which is another cost to transporters: the hours of downtime to recharge. They only make very limited sense in very last mile scenarios in dense cities. Also coal is way worse to burn than petrol, and in China's case, it's mostly bituminous, one of the worst coals in terms of pollution.