For many years, one of the eco-whatevers big issues has been to force us gas-guzzling unwashed off our vehicles and onto public (government supported, paid for with your tax dollars) transport. Given that any sort of centralized, scheduled transport is an abject failure when it is employed outside of major metropolitan areas (intercity/interstate/intercountry isn't what I'm talking about here), even when gas taxes cost more than the gas itself, their next choice was "cleaner" or "zero emission" vehicles.
Of course, anyone of moderate congnitive ability can see that there's a problem here. Let's take electric vehicles--the ones meant to run on batteries and recharge between trips. Outside of initial cost, limited range/speed and long term maintenance issues (battery replacement is expensive), there are several big pollution issues to deal with.
First, you create a lot of pollution just manufacturing the thing. Metals must be mined, refined and crafted, plastics refined and formed, etc. Second, there are those batteries--lots of batteries. Typically some sort of lead-acid type, these things are environmental disasters if not recycled properly. (They're merely dangerous if you do the job right.)
Second, you have to generate electricity to charge them. OK, the greenies say we can use wind and solar and other "renewable" methods to generate the juice. The problems with these are that the wind doesn't blow steadily everywhere and solar is unreliable and expensive on a large scale, outside of very specific geographic areas. Biomass might work, but methane stinks. (Don't believe me? Drive by a commercial chicken raising operation in high summer. Don't eat luch before this experiment. Trust me.) And all of these technologies generate huge NIMBY (Not In My BackYard) outpourings when someone is crazy enough to actually try employing them.
The current craze is hybrid cars and trucks, such as the Toyota Prius. My employer has one of the early versions of these, and while it drives just fine, there are some problems, such as the batteries again. I will admit it's an improvement over the all electrics, especially if your driving is mostly in the city. However, the greenies still aren't happy, since it burns evil petroleum products.
For some years, our ecologically-correct friends have been salivating over hydrogen power. Many folks, far smarter than yours truly, have tried pointing out that hydrogen has the same issues (minus the battery business) as the electric car (as Jerry Pournelle has put it so many times, there are no hydrogen wells), but hydrogen-powered vehicles have remained a Holy Grail (if those of the Earth Mother persuasion will permit me a religious reference).
Well, it seems that the critics are starting to get a hearing. FOXNews has this piece, short though it may be, on the problems. Perhaps we can save ourselves the next "this will save the planet" craze if we can just get some people to listen.