News Excerpt:

The Indian Space Research Organisation (ISRO) has successfully tested a 100 W class Polymer Electrolyte Membrane Fuel Cell based Power System (FCPS) in its orbital platform, POEM3, which was launched onboard PSLV-C58.

Objective of the experiment:

• To assess Polymer Electrolyte Membrane Fuel cell operation in space and to collect data to facilitate the design of systems for future missions.

About Polymer Electrolyte Membrane Fuel Cell:

• Fuel cells are generally classified according to the electrolyte and its ionic conductivity, which can be - 

• • Hydrogen ions or protons (H+):

• • • Polymer Electrolyte Membrane Fuel Cells (PEMFC) 
    • Phosphoric Acid Fuel Cells (PAFC).

• • Hydroxyl ions (OH-):

• • • Alkaline Fuel Cells (AFC)

• • Carbonate ions (CO32-):

• • • Molten Carbonate Fuel Cells (MCFC) 

• • Oxide (O2-):

• Solid Oxide Fuel Cells (SOFC). 
• The key component in a PEMFC is the proton exchange membrane. 
• The most widely used is perfluorosulfonic acid (PFSA) membranes with perfluorinated backbones and sulfonic acid as the terminal group.
• The membrane conductivity depends on a certain amount of absorbed water on the sulfonic sites. 
• This strong dependence of conductivity on water content makes it necessary for the PEMFC system to carefully manage the water balance through evaporation and condensation of water at a temperature close to its boiling point. 
• This links up the air humidity, airflow rate, system pressure, and stack temperature during the PEMFC construction and operation. 
• The presence of water in the system also limits the operational temperature, typically set at 80°C. 
• At this temperature, the PEMFC has poor tolerance to fuel impurities (e.g. CO), which results in bulky and complex fuel processing units for CO cleanup when hydrocarbons or alcohols are used as fuel via reforming.

Significance of the Polymer Electrolyte Membrane Fuel Cell:

• The fuel cell generated 180W power from Hydrogen and Oxygen gases stored onboard in high-pressure vessels during the short-duration test.
• It produced electricity directly from Hydrogen and Oxygen gases, along with pure water and heat. 
• It is an electric generator that works on electrochemical principles, as in batteries, as opposed to the combustion reactions employed in conventional generators.
• The ability to produce electricity directly from fuels without intermediate steps renders them very efficient. 
• With water as the only byproduct, they are totally emission-free. 
• These features make them ideal candidates for human space missions where electric power, water and heat are essential since a single system can meet multiple requirements in the mission.
• Fuel Cells also possess significant societal application potential. 
• They are considered the most appropriate solution to replace the engines of various vehicles today and power standby power systems.
• It can provide range and fuel recharge time, equaling today’s conventional engine, giving it a distinct advantage over batteries, and is expected to facilitate emission-free transportation.

About the POEM (PSLV Orbital Experimental Module) initiative:

• ISRO’s POEM platform has standard interfaces and packaging for power generation, telemetry, telecommand stabilization, orbital-station keeping, and orbital maneuvering. 
• This allows space agencies and private companies to design, develop, and validate experimental orbital payloads.
• Under its standard configuration, ISRO’s PSLV rocket is a four-stage rocket. 
• The first three spent stages fall back into the ocean, while the final stage (P4) ends up in space as junk after launching satellites into orbit. 
• However, the POEM initiative uses the spent final stage as a “stabilized platform to perform experiments.

About Fuel Cell-based Power System (FCPS):

• The FCPS payload is significant as it has potential applications in India’s space station, which is proposed to come up by 2035.