The Politics of Green Motoring

Feeling good because your car runs on unleaded sulphur-free fuel? Think again!

A car running on unleaded fuel pumps out (on average) over twice its own weight in carbon dioxide and carbon monoxide each year. This has a significant impact on global warming and health.

The only really clean fuels are electricity (bit of a pain to go long distances) zinc, boron and hydrogen. Hydrogen has to be one of the preferred choices since it burns to give water only, which would cause no environmental damage. Details about zinc and boron alternatives can be found at external locations since I have little knowledge about them, but they both have 'clean' usage cycles with no environmental damage as long as the initial energy comes from a clean source (same as for hydrogen). They are also both stable for transportation, though the waste product (that is effectively recycled back into fuel) has to be carried in the vehicle giving a weight issue. Check the pages and make your own decision.

Apart from working in internal combustion engines and jet engines with minimal adjustment, hydrogen can be used even more efficiently with fuel cells (actually invented last century and used extensively in powering space vehicles). These do not really burn the fuel but produce electricity, allowing quieter and more efficient vehicles to be produced. What's more, they can be refuelled quickly, dramatically extending their range.

So why can't we get a hydrogen-powered car now? Look at a few of the issues, read a about a series of programme designs for the "Perfect Car" or go to the links:

Is the technology available yet?

Yes it is. Fuel cell technology was invented before the internal combustion engine. Electric engines have been around for years and are still being developed for many applications. Hydrogen storage issues have been solved in many innovative ways.

Isn't hydrogen explosive?

Yes, and so it petrol. Worse, petrol is heavier than air, so if a petrol tank is ruptured it is potentially more dangerous if it explodes. The same questions were asked about internal combustion engine cars when they came out.

Isn't hydrogen difficult to produce?

It is one of the simplest of chemical reactions. It comes from water or cellulose (paper, for example). One 'burned' it becomes water again, and you can re-extract the hydrogen. No loss of water, so side effects. There are several methods of hydrogen extraction, the one most of us know being electrolysis.

Would you buy a hydrogen-powered car now?

No - because I couldn't refuel it. No petrol stations supply hydrogen.

Would a manufacturer build a hydrogen-powered car now?

No - because no one would buy one because there is nowhere to refuel so they couldn't use it anywhere.

Would a petrol station owner offer hydrogen?

No - because it is too expensive to install and no one would use it since no one has hydrogen-powered cars. It would never pay for itself. Besides, most are owned by oil companies who have little capability with hydrogen and so are not going to invest millions in something with so little return. We'll wait until there are enough hydrogen-powered vehicles on the road to warrant it.

Can we solve the hydrogen availability dilemna?

We could try cars which can run on multiple fuels. These will be more expensive and make people less likely to buy them.

Any other alternatives?

Doesn't production of both electricity and hydrogen take the pollution elsewhere?

Yes, it puts it back to the energy production centres, many of which use polluting methods to produce power. But this is much easier to deal with than cars, since it is more regulatable. We are already starting to see a switch to cleaner energy production with wind, wave, solar power etc. (check out the house in Oxford which is a net supplier of energy to the National Grid).

Links and information

Here is a good page about hydrogen powered-vehicles.

This is a design for a series of six programmes around designing the Perfect Car. They were going to build it as they made the programmes, but I don't think they ever got anyone to agree to buy it.

Programme 1 Traffic
Programme 2 Fuels
Programme 3 Motive Power and Performance
Programme 4 Materials
Programme 5 Production
Programme 6 Marketing and Legislation

A research paper excerpt on hydrogen storage:

The goal of this work is to develop a storage method that will permit large amounts of hydrogen to be stored and transported safely, effectively, and economically. New, high-strength glass microspheres (essentially, tiny bubbles) can be filled with high-pressure hydrogen for convenient bulk storage and transport. The walls of these microspheres, which can be 25 to 500 microns in diameter, are about 1 micron thick. We can fill them with hydrogen by first immersing them in a high- pressure bath of hydrogen and then raising the temperature of the glass to 200- 400 C. At this elevated temperature, the glass becomes highly permeable to hydrogen and the spheres fill up. Cooling the microspheres to room temperature traps the hydrogen in them. The glass microspheres then become safe, cost-effective carriers for the hydrogen. Heating the microspheres again releases the hydrogen in them.

Commercially produced microspheres for hydrogen storage were first studied in the late 1970s. These microspheres usually had defects that limited the hoop stress at failure to 50,000 psi. Researchers at Lawrence Livermore National Laboratory developed a method for producing much stronger, defect-free microspheres. These engineered microspheres have a hoop stress at failure of about 150,000 psi, permitting a threefold increase in the pressure limit for the engineered microspheres. Engineered microspheres could make the storage and transport of large amounts of hydrogen much more efficient. An analysis indicates that hydrogen in glass microspheres that is transported by rail can be economically competitive with liquid hydrogen.

Recent Advances:

The design for the pressurized, heated test system is complete. Hydrogen will be provided at pressures up to 8500 psi into a temperature-controlled chamber. Temperatures can be controlled from 20°C to 350°C. Hydrogen will be provided from a prepressurized cylinder rated for 30,000 psi operation. A preheater volume and valve will permit the sequential process of heating the spheres in the absence of high-pressure hydrogen, and then exposing them to the preheated high-pressure hydrogen. This will, for the first time, permit an accurate measurement of the hydrogen uptake rates by the spheres for a given temperature.

Microsphere bed loading will be accomplished by exposing heated microspheres to heated hydrogen. The increased permeability of the glass permits rapid loading of the spheres to the external pressure. When the temperature is reduced to room temperature, the permeability decrease "traps" the hydrogen in the spheres.

And see here for another hydrogen storage solution.

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