Electrically powered automobiles are a true vision of our future. Potentially very quiet, no emissions, and the ability to recharge at your own house. However, the intrinsic danger of chemically reactive batteries (like Lithium-Ion's) can cause some fear and reservations about the true safety of tomorrow's electric cars. Batteries have tendencies of shorting, or leaking, which can lead to 'thermal runaway', which boils down to a big fire that's not easily put out by foam or water. Among other problems, the fire and caustic risk potentials of large rechargeable batteries has loomed large on the electric vehicle horizon. This is obviously not a permanent problem to electric vehicles, but it's a massive one that is still being dealt with today by battery engineers. It's simply a matter of size/power storage, batteries that will be required to move a car hundreds of miles on a single charge will naturally have to be quite large, or in lieu of size, there will have to be a larger number of smaller batteries. With such an enormous effort being put on plug-in cars from the auto makers and even the federal government, one would assume it be only a matter of time before practical models become available to the public. But we still have a long road of safety testing to travel before plug-ins become an every day reality. Until then, the internal combustion engine will reign supreme, and they're becoming increasingly thirsty for bio-mass based renewable fuels.