[constant thinker]

Wasn't the movie called Flubber? That's a really old movie. Imagine if some one invented it in real life. I'd be in the market to buy some.

[ATMyller]

Alcohol is the most practical replacement so far. There is actually 85% alcohol, 15% hydrocarbon mixture aviable as gasoline replacement. It's called E85 and it's suitable with most modern cars with little alterations. Hydrogen ICE and hydrogen fuel cells will have to wait until the problems with storaging hydrogen has been solved. IMHO pressurized tank is too much of a risk since there are still people who crash their cars.

[Equi]

IMHO pressurized tank is too much of a risk since there are still people who crash their cars.

Or other people who trash their cars...

[P-man]

I thought of it but it's a fuel, not a new engine type. I could have done a list like this:

Hydrogen
Ethanol
Biodesiel
Other Alcohols
Electricity

[constant thinker]

There has been a lot of talk about fuels that are mainly grain alcohol. Right now the worry seams to be not enough supply for the demand. I don't how factual that is though.

If the U.S. Midwest can ramp up grain production and subsequently it's ethanol production I think that alcohol-hydrocarbon mixtures will start to be more prominent in the U.S. probably (hopefully). It will be interesting to see what happens in the next couple of years.

Maybe some engineers will figure out a good way to store hydrogen and be able to fill the tank fast..

[Yggdrasil]

The ethanol fuel produced from corn is, in my opinion, not a viable option for an alternative fuel.  As constant thinker mentioned, there is not enough supply for the demand.  Currently, producing the ethanol to provide 1.3% of the total energy used by the transportation sector requires 3.3 million hectares and 14% of the country’s corn production.  Furthermore, because corn is an important source of feed for livestock, critics of ethanol fuel claim that fuel ethanol production is raising the price of meat, milk, and eggs in the US.

However, the most damning argument against fuel ethanol is that it takes a great input of energy to produce ethanol.  As chemists, we should alll know that producing the 99.5% pure ethanol needed for fuel ethanol (so that the water doesn't cause the ethanol to separate from the gasoline in a gasohol mixture) from the 8% ethanol solution produced by yeast requires multiple distillation steps, which requires large amounts of heat.  The distillation and other steps are so energy intensive that experts estimate the input energy is somewhere between 80-130% of the energy contained in the ethanol produced.  So, using pessimistic estimates, you actually lose energy by producing ethanol.  Because the energy used in the production of ethanol comes from power plants which burn fossil fuels (mostly methane), ethanol produced from corn does not reduce net greenhouse gas emissions by much (in fact, similar reductions in greenhouse gas emissions could be achieved by switching to gas-electric hybrid technology).  Balanced against these moderate reductions of greenhouse gas emissions, however, is air and water pollution produced by the biorefineries and distilleries producing ethanol.

Ethanol produced from cellulose solves some of these problems because cellulosic ethanol uses agricultural wastes as feedstock.  Indeed, BP estimates that cellulosic ethanol could meet 30% of fuel demand without affecting food production.  However, cellulosic ethanol does not solve the fundamental problems of the energy requirements, nor does it solve the problems of the pollution from biorefineries.  With cellulosic ethanol, although the yield of sugars is theoretically higher since plants contain much more cellulose than starch, problems arise with breaking down the ethanol into simple sugars (glucose) for the yeast ferment (since yeast cannot ferment cellulose).  The costly breakdown steps partly counter any increases in energy efficiency gained from the higher yield of ethanol.

There are some solutions to these problems, such as genetically engineering yeast to withstand higher concentrations of ethanol or engineering enzymes to allow the more efficient hydrolysis of cellulose, but, like hydrogen fuel cell technologies, these technologies require more decades before they can reach the marketplace.

[constant thinker]

Another plan I heard was replacing MTBE (methyl tert-butyl ether) with ethanol. I don't know if it's happened and haven't found any articles on it other than a short snippet that told me about the idea.

To me this is makes plenty of sense seeing as MTBE is a carcinogen.

Yggdrasil, I most definately agree with you. Electric-gas hybrids will probably be the way of the future until hydrogen or some other fuel source delivers the world from it's oil addiction. When gas prices first shot up (in the U.S.), I remember hearing about shortages of the Toyate Prius and people being put on waiting as long a year in some places.

[P-man]

Why were they using their cars, then?

[Yggdrasil]

Replacing MTBE with ethanol would definitely be a good way to stimulate growth and investment in the biofuels industry.    I believe California has already introduced legislation to phase out MTBE, so ethanol will definitely be poised to replace MTBE there (plus I think CA also has incentives and subsidies for using ethanol anyway).  While I support replacing MTBE with ethanol, people should realize that ethanol costs much more than MTBE.  This means government subsidies (i.e. taxpayer money) is going to the agricultural sector to produce this ethanol for gasoline.  I personally think that phasing out such a permeating chemical contaminant is worth the funding, but others disagree.

[Borek]

The distillation and other steps are so energy intensive that experts estimate the input energy is somewhere between 80-130% of the energy contained in the ethanol produced.  So, using pessimistic estimates, you actually lose energy by producing ethanol.

That's not only distillation - you have to use a lot of fuel at field to grow and harvest plants. Perhaps Geo or Eugene will be able to comment futher - AFAIR from my technology classes distillation is not as energy consuming as it is commonly believed, as most of the heat can be reused.

[Donaldson Tan]

This might be a viable choice

LOL. It will definitely be faster than a ferrari..

[xiankai]

hah, now we need to wait for the 9.99 x 10⁴⁰
 other particles to arrive

[Dude]

Here's an interesting academic exercise.  How many miles per gallon do you need to obtain from a machine to overcome the differential in the respiration rate of a human.  For example, let's say you need to get from point A to point B and it is 80 miles away.  If you ride a bicycle, you're respiration rate will likely increase significantly (perhaps 2-3 fold) during the trip and hence CO2 will be expelled.  If you ride a machine, you're CO2 will be at a steady state but the machine will be using fuel.  What fuel efficiency is required to become more efficient than a person's biochemical energy?

[Borek]

You may assume burning about 500 kcal per hour when biking compared to 130 kcal per hour if you drive car by yourself.

[mrdeadman]

mini nuclear reactor?

this one gets my vote. everything else doesn't have enough power to weight potential to put a smile on my face like a gasoline engine can.