People have been promising stuff like this for about the last 30 years though - in fact i remember being at a brummie car show as just a little lad and passing the regular honda "concept" stand where amongst all the odd vehicles using nailbrushes instead of wheels etc, they had a pair of scooters... one running off water, one on bleach (yes, wierd choice aint it! hydrogen peroxide type rather than chlorine, i reckon).
never heard from again of course.
Still this is possibly related to a toyota advert i've seen pop up (TV? internet? can't remember) where they talk about using specially bred extremophile bacteria that actually break water down into hydrogen and oxygen as part of their natural metabolism (there's UBER STRANGE biological things happen in sulphur pools and ocean floor volcanic vents). It could be taken in different directions - mass production and distribution, if they can make it industrially viable (large scale production of ethanol is a largely microbial process, so why not?), or even coming down to having a reactor tank on board that you put water into.
For now though, my money's with the recent quite shocking advances in battery and charging technology, along with small size but large scale production of solar and wind generators. That stuff can happily sit on your roof or in the back garden and put enough juice in over a weekend or a night to get you to and from work in a smart car type vehicle. No further mind, but it's a start.
Let's just see... My first encounters with rechargable batteries was about fifteen years ago as a little kid with a fisher price tape player - a nickel cadmium AA would have about 500 to 650mAh maximum charge capacity and take upto 16 hours to fill, plus you had to be very careful to avoid "memory effect". The very latest thing i've seen in the last few weeks are 2500mAh NiMH cells - needing no more material, space, or being heavier than a regular battery - with a charger that can bring them back up to capacity in as little as fifteen minutes, and are damn near immune to memory effect problems. And they're being sold as affordable (not yet "cheap", but hey..) mass-produced consumer items, not highly expensive specialist goods.
I don't know how either of the Nickel technologies - or Lithium Ion, or Oxyride* - compares to the usual Lead-Acid car batteries used both for starter motors and a great majority of electric vehicles... but if we assume Acids have similar capacity and charging characteristics to a regular Nickel Cadmium... that'd mean a fourfold increase in range (from say 35 to 140 miles) and a reduction in "refuelling" time from silly street down to something that's actually practical. Fifteen minutes, every 140 miles (say every 2-3 hours?) - just enough for a wait in the payment queue, a much needed toilet break, a coffee, and a short browse through the magazines... get it down to five and you're laughing, as you can then have similar throughput to a standard petrol station even if everyone needs a complete recharge. Problem is, if you think of the power even a modest electric car would use, there's a whole lot of extra generating capacity going to be needed (not to mention the enormous current going into the charge circuits!)... but at least that can come from, to be honest, almost any source capable of rotating a generator shaft or otherwise mobilising electrons around a circuit.
Beleive it or not though, even a 30-40 mile range electric car, with two seats and a top speed of 45-50mph would be ample for most commutes (how many of you go more than 15 miles to work, regularly get over 55mph during it, or carry even one passenger?), it's crazy that HM Govt doesn't promote it a lot harder - but then i guess that would violate their war on the "two car family" by providing yet another set of wheels (anyone care to tell them a person can only drive one car at a time?), and would lose a
hell of a lot of revenue in petrol duty, congestion charging, and reduced rate road taxes.
Personally if i had to have one car, an electric would have to have four seats (even if squashed), be able to maintain at least trucker speeds on a regular motorway, and hold out at that pace for at least 150 miles without timeout being taken for a recharge - which would mirror the journey i had thursday (home-nottingham college-birmingham centre-home) and represents the longest non-stop trip i ever typically take, plus a little leeway. But i'm sure they'll get there fairly soon anyhow.
*Oxyrides seem to be the new "thing" in non rechargable cells - different chemistry to alkalines, they offer better staying power by starting at 1.7v and falling thru 1.5 and then on to lower voltages as they discharge ('failing' on e.g. most digicams once it goes under about 1.2v) - rather than starting at about 1.5v like a standard cell. I was skeptical at first, just bought them as they were the only AAs left to buy and i was in a hurry ... but they really did live up to the packet claim of delivering 3x the usual runtime. Clever stuff. Now, if someone can do the same for rechargables, that'd be magic - a higher voltage means more stored energy per mAh after all 