First, Ethanol does require fuel input to make. Currently this process still yields about a 30% net energy gain from processing. Other materials are better suited to this process and bacterial or catalyst assisted conversion processes are in development and hope to improve this dramatically.

Second, the energy input required for conversion can be substituted with just about any system other than fossil fuels commonly used. Only heat is really required. Using solar heat or wind-to-electric energy is also possible for ethanol conversion. Other common farm processes can also be used to generate this heat which by the way themselves result in usable byproducts (charcoal)

Next, Ethanol production also yields material waste, which can be converted to charcoal (and provide heat in the process to make more ethanol!). This charcoal can be sold to power plats in place of coal. It's actually both cleaner AND more efficient for use in power generation than coal. The output of the coal power plants can be flushed through algae and other materials yielding a very powerful fertilizer which can be provided back to farmers for ethanol plant growth.

Ethanol can be used to power the vehicles that move the fuel and materials back and forth. More detailed explanations about how this all pulls together are found here: http://www.theoildrum.com/story/2006/11/27/0432/3533

OK, now onto Hydrogen. Not only is it less efficient for direct combustion, cost nearly 5 times as much to produce, and the fact that we have to worry about boil off, we're talking about giving people mobile bombs to drive around in!!! Fuel cells work OK for making electricity on large scale, but are almost worthless for small vehicles. We're 20+ years from sufficient battery and motor technology to work this out.

Nuclear?!? We have at best 30 years of nuclear fuel at our current rate of use. We'll be out of it before we're out of oil or natural gas. Even if we bring online a dozen condensers, we're still looking at maybe 75-100 years of fuel. Besides, making a nuclear generator small enough to go in a car is at least 50 years off.

Wind, water, and solar power backing up plugin/ethanol hybrid's using recyclic turbines for electric power instead of typical combustion engines will give us plenty of power to move even 18 wheeled trucks, will more than triple current fuel economy, and it CAN be done. In fact, we can do it at a PROFIT of about $400 per person per year vs current fuel technology, and we can start today. Lets get that start by making farmers plant ethanol crop in their empty fields that their currently being paid not to plant tobacco in...

Oh, 1 last thing. FORGET CORN! It's not good enough. There are crops that produce more ethanol per yield with more yields per acre per year, and they cost less to grow, harvest, and process than corn.

"Few are saying so openly, but it appears that any truly zero-carbon car of the future would be ultimately dependent on nuclear power. "

Thats the rub of it.

Only thing is that we (Nuclear capable countries) need to create safer nuclear plants as well as recycling facilities.

But there's the attitude of "not in my back yard" and the need for security of the plants and the fuel.

While the logistical and technical issues can be ironed out, the big issue is selling it to all those who cringe at the word nuclear.

Remember. Medicine had to change the name from NMR to MRI so they wouldn't scare their patients. ;-)

There's quite a string of nonsense in this article.

You dismiss battery technology in a sentence and go on to extol the wonders of hydrogen ICE and fuel cell technology.

Hydrogen technology is not nearly there. Everyone knows that, but what a lot of people miss is that battery technology IS there. All the engineering problems that troubled battery electric vehicles have been overcame. We now have fast recharge times, very high energy densities (e.g. Lithium-Sulphur) and if we can get the economies of scale, then battery technology can be the energy solution for our cars.

We already have an electricity distribution network, why develop a hydrogen economy when it's not needed. Who does that benefit?

(Battery link: http://www.a123systems.com/html/news/articles/051102_news.html)

Also, to add another point against bio-fuels, the argument that they are carbon neutral is non-sense. Apart from the vast amounts of processing involved in producing the fuel, the land used for growing these crops most often already has carbon absorbing vegetation that is already part of the carbon cycle. In this way, we are not taking any more carbon out of the atmosphere in growing the fuel and we are releasing carbon on burning the fuel.

Finally, bio-fuels do little for our air-quality. This is an important issue and any genuinely green approach should look at cutting down on the burning of hydrocarbons.

Haven't you heard about the Tesla Roadster? Does 0-60 mph in about 4 seconds, 130mph top whack and does 250 miles on a single charge. Admittedly, it currently costs rather a lot (50k) but it shows that the technology is already here for a viable electric car. It looks hot as hell too, so you can be green and still drive like a twat. I want one!

Have a look at http://en.wikipedia.org/wiki/Tesla_Roadster for details or better still, check out http://news.bbc.co.uk/nolavconsole/ukfs_news/hi/bb_wm_fs.stm?news=1&nbram=1&nbwm=1&bbram=1&bbwm=1&nol_storyid=6191957 to see one in action on the road.

One thing about batteries is that they don't last forever. You have to replace them at some time.

Not only is it costly, but most batteries contain some pretty hazardous chemicals. Some of that can be recycled, but some of it is going to need to be dumped somewhere.

On the ethanol issue, I am under the impression that some methods are more wasteful than others. In the US, they make it from corn grown specifically for that purpose. In Australia, it's mostly made from molasses, which is a byproduct of sugar production... It's made anyway, so it's not as wasteful.

Let’s not forget PML’s Mini QED http://www.pmlflightlink.com/archive/news_mini.html

640bhp, 0-60 in 4.5sec

65-80mpg, 4hrs on battery only

I drive a ethanol car, SAAB biopower 2.0t, the new one 2.3t is even more efficient. In the medium to long term, we should stop using foodstuffs to make fuel but cellulose. I live in the vodka belt, Norway, Sweden, Finland, Baltics and Russia. Most people know how to make home brew ethanol substances from food by-products (e.g. potato skins).

Just discussed all this ethanol issues on my blog: http://blogs.sun.com/ValdisFilks/entry/the_truth_is_rarely_pure

Of course, the greenest thing to do might be to keep running your old car, use 5% ethanol/petrol mix or retrofit an ethanol fuel converter. That way you avoid the huge carbon cost of the initial manufacture, which is just as high for a new hybrid or green car as for a gas-guzzler.

In Ireland, E85 is manufactured from whey - a byproduct of cheese manufacture. Given that cattle are responsible for 18% of greenhouse gas emissions, using this byproduct to reduce car transport emissions is a good thing.

First, current diesel engines can be as efficient as current hybrid

designs.

Ethanol from corn is soo inefficient and uses so much land to grow

that it is pushing up the price of food in the US and Mexico to the

point of food riots.

Biodiesel is not mentioned, but since most of it comes from plantations

that were once virgin rainforest, that is just as well.

You can forget electric /plug in hybrids at least in the UK - we will be

facing an accute electricity crisis here within 10 years as coal and

nuclear plants are decommisioned, and natural gas gets ever more

expensive. We won't have the spare energy.

And you can forget business as usual. Worldwide oil production has

been stuck at 85M barrels/day for the last two years, but demand is

accelerating. Within 5 years global supply will go into irreversible decline.

There is only one solution - we are all going to be driving a lot less in

future whether we like it or not. Technology will not save the automobile.

i have to say after reading... "A couple of points to make" article. It has indeed opened my eyes. but where do we get info about solar power for the car etc... you said we can start now.

"The Prius shows to great advantage in stop-start city driving, where normal vehicles produce huge amounts of poisonous emissions."

Don't know where you've been in the past 20 years, but since catalysts were introduced the levels of nasty stuff coming out of car exhausts has dropped by over 95%. Admittedly, lean-burn has been a casualty of this legislation so overall fuel consumption (and therefore CO2 emissions) have gone up. Cars have also gained a lot of weight due to safety requirements, causing a futher increase in CO2. All those batteries do add to the weight...

I hope the lithium batteries used in modern hybrids don't behave like laptop ones have.

Couple points about lithium batteries.

1. Only 4 countries in the world have lithium.

2. GM Volt, electric plug in car which uses lithium batteries, had very inconsistent battery life ie 2 months to 5 years.

3. Electric cars sound great but Northern Hemisphere countries with cold climates are not suited to batteries. Try starting an electric car in 30 below and the performace of the battery is reduced by 50%.

Cheers

Where is the "grow more hemp" crowd?

Having said that - the only hope for our current way of life (WOL) is nuclear fusion.