In 1970 the environmental movement was just beginning, and steam cars were being suggested as an alternative to fossil fuel-powered automobiles. That year, General Motors built a steam car and put it on display at the Detroit Auto Show. The car was a Pontiac GTO with an extended hood and a trunk full of relays; it even had an air conditioner. It was the perfect way to demonstrate that steam cars could be very nice, and quite impractical. General Motors did not want to do anything but continue to sell gas-guzzlers.
By Dr. Angus macDonald
Published: August, 2005
In 1970 the environmental movement was just beginning, and steam cars were being suggested as an alternative to fossil fuel-powered automobiles. That year, General Motors built a steam car and put it on display at the Detroit Auto Show. The car was a Pontiac GTO with an extended hood and a trunk full of relays; it even had an air conditioner. It was the perfect way to demonstrate that steam cars could be very nice, and quite impractical. General Motors did not want to do anything but continue to sell gas-guzzlers.
In 2005, we still have a pollution problem, and General Motors is selling Hummers. Today, people hear about a "Hydrogen Economy" and Governor Schwarzenegger’s "Hydrogen Highway," but it is just another smokescreen, so the auto industry can continue business as usual.
The 2005 hydrogen car is really the 1970s steam-powered car all over again. Hydrogen combined with oxygen forms water, so what could be cleaner than a Hydrogen car?
Hydrogen, like steam, is a perfect, clean fuel, storing more energy per pound than almost anything else. It is even used in the Space Shuttle. Could the "Hydrogen Highway" really be a solution for our pollution dilemma? Even with all the very real advantages of hydrogen-power, no one wants to talk about the intractable problems.
The steam car certainly had problems being able to withstand maximum pressure and temperature, which limited its efficiency. There is also the possibility of the water turning into ice and bursting the pipes. Sometimes there really is a gorilla in the closet. The hydrogen car gorilla is even bigger.
Even though, the source of hydrogen is plentiful - water, separating hydrogen from the molecular structure of water costs energy; and you do not get a rebate when you recombine hydrogen with oxygen to drive. Bang goes the efficiency, right there.
Also, let’s assume that in a nice, new, nuclear power plant there is enough energy to make a large supply of hydrogen. How then do you transport it? Oops, hydrogen is a permanent gas that, unlike propane, cannot be compressed into a liquid. Consider that the fuel is transported by vehicle in pressurized tanks to prevent fuel from evaporating, so a liquid under mild pressure is acceptable.
Carrying this highly-compressed gas in a big, heavy cylinder costs money to run the compressor, and to haul the weight of the cylinder. Back at the plant, the energy required to make the hydrogen also comes at a cost. My, my, the hydrogen gorilla is beginning to look like an alpha male.
Remember, the object of the exercise is to reduce the pollutants in the air, and reduce the amount of carbon dioxide (CO2) emissions. A motor fuel should not only burn cleanly, but be easy to carry around.
In terms of energy stored per pound, there really isn’t anything better than carbon-hydrogen bonds (CH2). A string of carbon atoms with hydrogen attached with extra hydrogen attached to the ends, is about as good as it gets. In terms of an engine fuel, more hydrogen and fewer carbons are better because two hydrogens need one oxygen molecule, and every carbon needs one oxygen molecule to burn. Fewer carbons mean oxygen molecules get to the burning hydrogen molecule faster and burn cleaner. These compounds are called paraffins. All they do is burn, but they are seriously, non-reactive chemicals.
The series of paraffins, each with more carbon, is: methane, ethane, butane, propane, pentane, hexane, heptane, and octane. Octane is gasoline that can be kept in a tank, because it does not evaporate quickly, and gasoline stores lots of energy per pound. It is not a surprise that gasoline is the fuel of choice for cars, but any of the lower-carbon paraffins would work: Methane (natural gas), but it is a permanent gas at room temperature, as is ethane. Liquefying butane requires rather high pressure, propane — now there’s a fuel for internal combustion engines!
Propane is only four carbons long so it burns cleanly. Forklift trucks used indoors burn propane with crude, Model A engines without pollution gadgetry, and without stinking up the air in a warehouse. The propane molecule is not too big, so it doesn’t run out of oxygen as it burns, and it has the most hydrogen per unit carbon of any fuel we can carry about readily. But oil companies don’t want anyone to use propane because they would have to rework all the refineries.
In Australia’s metropolitan areas, there exists today a network of 35,000 service stations that dispense both gasoline (petrol) and what they call "autogas", a mixture made mostly from propane and butane, also referred to as LPG (liquefied petroleum gas). Cars in Australia are routinely converted, and some manufacturers supply dual-fuel vehicles. Here in the States, automakers and refineries would have to retool, so, there is less enthusiasm, even though propane-powered cars could have higher compression, improving efficiency.
Thus, we have pure hydrogen as the perfect red herring. Years could be spent chasing the hydrogen dream and none of the economic problems solved. The reason that we do not drive propane cars is simply because it would be expensive to change things around and use propane in lieu of octane.
Now consider tailpipe emissions. The larger the carbon chain, the less oxygen is available for combustion, so, the stinkier the exhaust. Propane burned in a Model A engine smells okay. Never discount the nose as a chemical analyzer. If you think research scientists do better, think again. If it stinks it’s bad for you: that is why it stinks, as evolution has given us an olfactory organ to sense and avoid bad things.
Diesel oil (kerosene) has lots of carbons in a string. When burned, the oxygen gets used up quickly, and the carbon left over leaves all kinds of foul, smelly carbon and nitrogen compounds, most all of which are seriously bad for you.
Propane, with its only four carbons and 10 hydrogen molecules; uses less oxygen, burns slower, and when combustion is complete, has eliminated any stranded carbons.
Gasoline (octane) has eight carbons and requires twelve and a half oxygen molecules. Oxygen in the air runs out before combustion is complete.
This is not rocket science, rather it’s ordinary chemistry that is seldom considered. In a sense, it’s the sensible Hydrogen Highway.
Instead, our government encourages the purchase of Hummers by giving a tax break to commercial vehicles over 6,000 lbs. Please buy a Hummer and get seven miles to the gallon.
More of the large, heavy, low-mileage vehicles on the road means it’s more likely that more parents will want to drive one — to protect their children in the event of a collision. But if the streets were filled with lighter weight vehicles, made from ABS plastic or aluminum, then these same parents could feel safer in smaller, lighter vehicles that use less fuel; but that’s not the way General Motors makes money.
It would be sensible and immediately beneficial to make lighter cars, even if fuel is expensive. Right now we would all pay about the same, while saving fuel. If you burn less fuel, pollution goes down, but it all follows the money.
