Ideally, a hydrogen fuel-cell vehicle has no environmental impact. Energy is produced by combining hydrogen with oxygen pulled from the atmosphere, and the tailpipe emission is water. The hydrogen fuel could come from a number of sources (Iceland recently started pulling it out of the ground).
A fast shutter speed such as 1/400th of a second will produce a series of crisp frames that have a choppy look when played back. A slow shutter speed such as 1/30th of a second, on the other hand, will produce a series of slightly blurred frames that have a smoother look when played back.
Slowest Practical Shutter Speed for Handheld? I have never heard of the film speed rule but I have heard of the lens focal lengh rule. I use the focal lengh rule alot but I have had good results at 1/8 and 1/15 of a second. I do mostly portaits so I use a tripod 70% of the time.