FUEL CELL POWER SYSTEM - SCI & TECH 
News: ISRO’s
Fuel Cell flight tested in PSLV C58
What's in the news?
●       ISRO
has successfully tested a 100 W class Polymer Electrolyte Membrane Fuel Cell
based Power System (FCPS) in its orbital platform, POEM3, launched onboard
PSLV-C58 on January 1, 2024. 
Key takeaways:
●       The
objective of the experiment was to assess
Polymer Electrolyte Membrane Fuel cell operation in space and to collect
data to facilitate the design of systems for future missions. 
●       During
the short duration test onboard POEM, 180 W power was generated from Hydrogen
and Oxygen gases stored onboard in high pressure vessels. 
●       It
provided a wealth of data on performance of various static and dynamic systems
that formed part of the power system and the physics at play.
Fuel Cell:
●       A
fuel cell is a device that generates
electricity by a chemical reaction.
●       Fuel
cells can be used in a wide range of applications, providing power for
applications across multiple sectors, including transportation,
industrial/commercial/residential buildings, and long-term energy storage for
the grid in reversible systems.
Working:
●       A
fuel cell consists of two electrodes
- a negative electrode (or anode)
and a positive electrode (or cathode).
●       Both
electrodes must be immersed in and separated by an electrolyte, which may be a
liquid or a solid but must, in either case, conduct ions between the electrodes
in order to complete the chemistry of the system. 
●       A
fuel, such as hydrogen, is supplied to the anode, where it is oxidised,
producing hydrogen ions and electrons. 
●       An
oxidizer, such as oxygen, is supplied to the cathode, where the hydrogen ions
from the anode absorb electrons from the latter and react with the oxygen to
produce water. 
●       The
difference between the respective energy levels at the electrodes
(electromotive force) is the voltage per unit cell.
●       The
amount of electric current available to the external circuit depends on the
chemical activity and amount of the substances supplied as fuel.
●       A
single fuel cell generates a tiny amount of direct-current (DC) electricity. In
practice, many fuel cells are usually assembled into a stack. 
Advantages of Fuel Cells:
●       Fuel
cells have lower or zero emissions
compared to combustion engines. Hydrogen fuel cells emit only water, addressing
critical climate challenges as there are no carbon dioxide emissions.
●       There
are also no air pollutants that
create smog and cause health problems during the operation of a fuel cell.
●       They
can operate at higher efficiencies
than combustion engines.
●       A
fuel cell resembles a battery in many respects, but it can supply electrical
energy over a much longer period of time.
●       Fuel
cell is an ideal power source for the
Space Station as it provides both power and pure water.