Today however gas turbine combined cycle powerplants are about the most efficient type of engine available.
Fuel cells are in about the fifth cycle of attempts to turn them into commercial reality.
At the time many experts predicted that around 2005 a large percentage of vehicles would be powered by hydrogen fuel cells, many buildings would be partially or totally powered by fuel cells, and a considerable percentage of electronic applications would be powered by micro fuel cells.
Every week or month a new supply of liquid fuel would be injected into the fuel cell.
Fuel cells are most ideal for electric power production because electricity is both the initial and final form of energy that is produced.
FUEL CELLS FOR TRANSPORTATION
Fuel cells are being proposed to replace Otto or Diesel engines because they could be reliable, simple, quieter, less polluting, and have even greater economy.
The internal combustion Otto or Diesel cycle engine has been used in automobiles for 100 years.
Autotrophic activityin plant cells occur in organelles called ...
SECOND LAW ANALYSIS OF FUEL CELLS
In Fig 10 the clausius energy efficiency of three proposed fuel cells are compared when operating on hydrocarbon fuel.
This would result in a higher efficiency than what the fuel cell can achieve by itself.
Unfortunately very small gas turbines are not nearly as efficient.
In spite of this gas turbines (with addition of heat exchanging or steam turbines) can be highly efficient in the large sizes and produce little pollution.
So, many types of fuel cells can run efficiently at low temperatures while at the same time converting very high temperature energy.
Present highly advanced gas turbines do not achieve a mean temperature of more than 1150°K or 877°C.
Present microturbines in the 30 kw range are only about 25% efficient even when heat exchanging is employed, though future ceramic microturbines in this size may achieve 35% efficiency.
In the future, medium and large powerplants using SOFC will be fuel cell gas turbine combined cycles.
The fuel cell does get hot but only because of the resistance and inefficiencies during the ion and electron flow during the production of electricity.
The carnot ratio only relates to the absolute temperature scale where 0°C=273.15°K degrees.
Heat engines such as gas turbines are considered to be inferior to fuel cells because they must convert the high chemical temperature of the chemical energy into low thermal temperature of thermal energy first.
FUEL CELLS vs HEAT ENGINES
The virtual photons that are transferred during the chemical reactions in a fuel cell have a very high chemical temperature somewhere between 3,500° and 20,000° Kelvin.
Chemical temperature ..is a new term that can be used to describe the energy contained in virtual photons for chemical energy with units of Kelvin  and symbol T just like temperature.
Light is composed of such real photons.
We could use Joules or BTU as a measure of the amount of energy that each real or virtual photon contains but it would be a very small fraction of a Joule indeed.
This virtual photon can under ideal conditions be transferred directly from the chemical system to another chemical system, electron, or ion by close contact, without being spilled to the surroundings.