One of the most fascinating technologies on the horizon is the hydrogen economy. Its beginnings are almost upon us, and the infrastructure for hydrogen fuel-cells could be ubiqutous by as early as the end of the next decade.
A fuel-cell is a device without moving parts whose fuel is pure hydrogen and whose exhaust product is plain water. Briefly, it works like this:
Hydrogen fuel is fed through a special membrane which strips the hydrogen of its electrons. The flow of electrons produces a current which can power an electric motor or other electrical device.
Then, on the other side of the membrane, the electrons rejoin their hydrogen nuclei (protons) and, in the presence of oxygen, convert to water. Properly maintained, the hydrogen fuel-cell is a zero-emission energy source.
Now critics have correctly maintained that hydrogen is not really an energy fuel but an energy carrier. That is, it takes energy to create hydrogen fuel from water, natural gas, oil or other sources, and thus the pollution and greenhouse gas problem is simply shifted to an earlier stage—that of hydrogen production.
This is true as far as it goes, but a deeper analysis reveals two important points:
–First, a fuel-cell/electric motor combination is capable of almost twice the fuel efficiency of the internal-combustion engine. Current internal-combustion engines, such as the one in your car, achieve a fuel-to-energy conversion of approximately 20-25%, with a theoretical maximum of about 30%. In contrast, fuel cells are capable of reaching a fuel-to-energy conversion of about 55%—almost double.
Thus a hydrogen economy powered by fuel cells would use about half the energy for the same amount of power. This would cut pollution and greenhouse-gas emissions by almost 50%, even if hydrogen were produced from or by hydrocarbon sources.
–Second, eventually hydrogen could be produced from plain water by renewable energy sources such as hydroelectric, geothermal, wind and solar. This would result in zero net pollution, and even more important, zero emissions of the greenhouse gases driving global warming.
Thus it is quite possible that the earth could, within a few decades, have a sustainable source of transportation and power that produces virtually zero pollution and zero carbon dioxide. This would be radical indeed.
Further, since vehicles sit idle about 90% of the time, fuel-cell vehicles could eventually become generating sources. As the technology for creating hydrogen fuel from renewable energy becomes localized, one's fuel-cell vehicle could be feeding energy into the electrical grid at night or any time the car sits idle.
This would transform one's energy bill into an energy check, in addition to providing millions of localized sources of electrical energy, thus drastically reducing dependence on centralized generators.
Not incidentally, this could also drastically reduce and eventually eliminate the current extreme dependence on hydrocarbon energy sources—which are not only polluting, but due to run out in a few short decades.
Small fuel cells can also one day power everything that is now powered by batteries, from cell phones to laptops, but with ten times or more the energy-life of current batteries.
The advent of the hydrogen economy—which is just a few miles up the road—will be a fascinating and revolutionary development on planet earth.
—jim sloman, 9/23/02 for 11/10/02
|
