Electric engines are 90-95 efficient in converting power to motion.
Even the very best experimental gasoline engines in Toyota's labs are around 30-35% efficient.
Even if all gasoline and diesel was used in massive generator units to produce electricity, EVs would still be better for the environment and the total gasoline/diesel usage would go down.
But the power plant has only slightly higher efficiency off the fossil fuels it burns. So you need to use the ev to store excess grid solar generated during the day to truly get an advantage
At least the power plant is burning that fuel and spewing garbage into the air in a place that isn't your home. And power plants capture more of that pollution than cars do, not to mention that many of them burn cleaner fuel than gasoline or diesel.
And most people tend to keep their cars for 10+ years. The power grid is changing all the time, and it's likely in the time that you own your EV, the sources it gets powered from will become cleaner.
It's also easier to regulate a few dozen power plants to become more efficient and force them to capture more pollution vs. doing that to 100 million cars on the road after the fact.
Even the very best experimental gasoline engines in Toyota's labs are around 30-35% efficient.
Even if all gasoline and diesel was used in massive generator units to produce electricity, EVs would still be better for the environment and the total gasoline/diesel usage would go down.