posted on Jan, 1 2007 @ 11:57 PM
Also, hydrogen is not a source of energy, but only a carrier of energy. As a carrier, it plays a role similar to that of water in a hydraulic heating
system or electrons in a copper wire. When delivering hydrogen, whether by truck or pipeline, the energy costs are several times that for established
energy carriers like natural gas or gasoline. Even the most efficient fuel cells cannot recover these losses, Bossel found. For comparison, the
"wind-to-wheel" efficiency is at least three times greater for electric cars than for hydrogen fuel cell vehicles.
Another headache is storage. When storing liquid hydrogen, some gas must be allowed to evaporate for safety reasons—meaning that after two weeks, a
car would lose half of its fuel, even when not being driven. Also, Bossel found that the output-input efficiency cannot be much above 30%, while
advanced batteries have a cycle efficiency of above 80%. In every situation, Bossel found, the energy input outweighs the energy delivered by a factor
of three to four.
About four renewable power plants have to be erected to deliver the output of one plant to stationary or mobile consumers via hydrogen and fuel
cells,” he writes. “Three of these plants generate energy to cover the parasitic losses of the hydrogen economy while only one of them is
producing useful energy.”
This fact, he shows, cannot be changed with improvements in technology. Rather, the one-quarter efficiency is based on necessary processes of a
hydrogen economy and the properties of hydrogen itself, e.g. its low density and extremely low boiling point, which increase the energy cost of
compression or liquefaction and the investment costs of storage.
The alternative: An electron economy
Economically, the wasteful hydrogen process translates to electricity from hydrogen and fuel cells costing at least four times as much as electricity
from the grid. In fact, electricity would be much more efficiently used if it were sent directly to the appliances instead. If the original
electricity could be directly supplied by wires, as much as 90% could be used in applications.
“The two key issues of a secure and sustainable energy future are harvesting energy from renewable sources and finding the highest energy efficiency
from source to service,” he says. “Among these possibilities, biomethane [which is already being used to fuel cars in some areas] is an important,
but only limited part of the energy equation. Electricity from renewable sources will play the dominant role.”
To Bossel, this means focusing on the establishment of an efficient “electron economy.” In an electron economy, most energy would be distributed
with highest efficiency by electricity and the shortest route in an existing infrastructure could be taken. The efficiency of an electron economy is
not affected by any wasteful conversions from physical to chemical and from chemical to physical energy. In contrast, a hydrogen economy is based on
two such conversions (electrolysis and fuel cells or hydrogen engines).
“An electron economy can offer the shortest, most efficient and most economical way of transporting the sustainable ‘green’ energy to the
consumer,” he says. “With the exception of biomass and some solar or geothermal heat, wind, water, solar, geothermal, heat from waste
incineration, etc. become available as electricity. Electricity could provide power for cars, comfortable temperature in buildings, heat, light,
“In a sustainable energy future, electricity will become the prime energy carrier. We now have to focus our research on electricity storage,
electric cars and the modernization of the existing electricity infrastructure.”
Citation: Bossel, Ulf. “Does a Hydrogen Economy Make Sense?” Proceedings of the IEEE. Vol. 94, No. 10, October 2006.
By Lisa Zyga, Copyright 2006 Physorg.com