I think that Toyota hydrogen fuel cell is far more practical and cleaner (because electric batteries are charged with coal fire plant electricity made 500+ miles away from where it is used).
Really? Hydrogen? Ok. First off, hydrogen is an energy carrier, not a source. Most hydrogen for transportation these days comes as a bi-product of fossil fuels. So that's not really so clean.
So what if we make the hydrogen from H2O using electrolysis...that means we split 2 H2O molecules into 1 O2 and 2 H2 molecules. There is going always going to be some heat generated in this process, which is by definition waste.
The real and fundamental flaw in this process comes next. In order to transport and use the hydrogen, you have to compress it. This takes energy. Extra energy. And when you compress a gas, it gets warmer. This is a fundamental law of physics. So we have compressed hot gas. What happens to that heat energy? It will certainly not be used to power the car. It will likely be wasted.
Next, you have to transport the compressed hydrogen gas. This also takes energy. Energy that will be lost.
Another large problem with hydrogen gas is that the molecules are small. Why is that a problem? Because it will be difficult to contain the gas. It will tend to escape. The gas will be lost in compression, in transport, and in storage. It is likely that if you fuel your hydrogen car up and park it, you will lose most of your fuel to the air in several days.
Finally, we have to change the energy in the hydrogen back into electrical energy to power the electric motors. The efficiency of fuel cells is an engineering problem, but I suspect there is some intractable physics in there that will cap the efficiency. Let's assume a best case scenario of perhaps 50% efficiency for the cells. That is still a lot of waste. However if you factor in the losses from electrolysis, compression, storage as well, you will have an overall efficiency less than 50%. Probably quite a bit less. So let's say for the sake of argument that the entire process is 30% efficient, which I suspect is generous.
It is well known that the electricity transmission system is highly efficient. Some easy research should tell you that the transmission system is more than 90% efficient. When we charge a battery, there are come losses. But they aren't that high. Let's assume the charging system is 80% efficient. Overall then, that process would be 72% efficient (I think it is higher than that actually).
So, if you have 100J of energy that you wish to use to drive the electric motors in a car, you can use hydrogen, and get less than 30J to the motors, or you can use the electrical grid, and get 70J to the motors. Honestly, why would you use hydrogen? Especially since the fuel cells would be complicated, expensive, and of unknown reliability. Hydrogen as a fuel is flawed at the level of fundamental physics. These problems cannot be engineered away.