Hydrogen Fuel Cell 

Context: The Prime Minister of India virtually launched India’s first indigenously developed hydrogen fuel cell ferry which will be deployed for service at Varanasi in Uttar Pradesh. 

About the Hydrogen fuel cell ferry: 

• The Hydrogen fuel cell vessel is 24-metre-long which can carry 50 people in its air-conditioned passenger area. The accommodation area has been constructed with high-quality fiberglass reinforced plastic, similar to metro train coaches.
• Manufactured by: Cochin Shipyard Limited
• Built at a cost of Rs 18 crore, the ferry will be handed over to the Inland Waterways Authority of India after rigorous trials. The Ministry of Ports, Shipping and Waterways met 75 per cent of the project cost. 
• This vessel uses a 50-kW PEM (Proton-Exchange Membrane/Polymer Electrolyte Membrane Fuel Cell Power System) fuel cell, with Lithium-Ion Phosphate batteries.  The vessel has five hydrogen cylinders that can carry 40 kg of hydrogen and support eight hours of operations. The vessel is also fitted with a 3-kW solar panel.
  • PEM fuel cells are popular in automotive applications because they operate at a lower temperature, and are lighter and more compact.
• The vessel has zero emission, zero noise and is energy-efficient, which makes it more environment-friendly. 

Fuel Cell:

• A Fuel cell is a device that converts the chemical energy of a fuel directly into electricity by electrochemical reactions.
• The most common fuel cell is a Hydrogen fuel cell, that combines hydrogen fuel with oxygen, to produce electricity, with water and heat as the byproducts. 
• The cell consists of a cathode (negative electrode), an anode (negative electrode) and an electrolyte (can be solid, liquid or membrane based). The electrolyte facilitates the movement of ions or charge carriers between the electrodes. 

Polymer Electrolyte Membrane Fuel Cell: 

• Also known as Proton Exchange Membrane fuel cells, use a polymer electrolyte membrane (PEM) as the electrolyte.
  • PEM is a solid polymer electrolyte typically made of a perfluorosulfonic acid material, such as Nafion. 
  • This membrane allows the transport of protons (H+) through the membrane while blocking the passage of electrons. It plays a crucial role in separating the anode and cathode reactions.
• Fuel: Hydrogen with oxygen as an oxidising agent. 

Working of PEM Fuel Cell: 

• Anode and Cathode: At the anode, hydrogen gas is typically supplied, and it undergoes electrochemical oxidation to produce protons (H⁺) and electrons (e⁻). The electrons flow through an external circuit, creating an electric current.
• Catalysts: Platinum or other platinum-group metals are commonly used as catalysts on the anode and cathode to facilitate the electrochemical reactions.
• Electrochemical Reactions:
  • At the anode: 2H₂→4H⁺ + 4e^-
  • At the cathode: O₂ + 4H⁺ + 4e^- →2H₂O
• Proton Exchange: Protons generated at the anode move through the PEM to the cathode, while electrons flow through an external circuit, creating an electrical current.

Characteristics of PEM Fuel cells:

• Operating Temperature: PEM fuel cells operate at relatively low temperatures (between 60-80 degrees Celsius), allowing for quick start-up times (less warm up time).
• Catalyst Requirement: To facilitate the separation of electrons and protons in hydrogen, PEM fuel cells use a noble-metal catalyst, typically platinum, leading to high cost.
• Carbon Monoxide Sensitivity: The platinum catalyst is highly sensitive to carbon monoxide (CO) poisoning. If the hydrogen used in the fuel cell is derived from a hydrocarbon fuel, it may contain trace amounts of CO. The presence of CO can significantly degrade the performance of the platinum catalyst, leading to a decrease in fuel cell efficiency over time.
• Carbon Monoxide Reduction Reactor: To address the issue of CO poisoning, an additional reactor is often employed to reduce the levels of CO in the fuel gas before it reaches the fuel cell. This reactor adds complexity and cost to the overall system.
• Water Management: PEM fuel cells require effective water management to maintain the hydration level of the PEM. Water produced during the electrochemical reactions needs to be removed from the membrane to prevent flooding.

Applications of PEM Fuel Cell:

• Transportation (such as fuel cell vehicles)
• Stationary power generation (backup power systems to power buildings)
• Portable electronic devices (laptops, camera, smartphones)
• Defence applications (Powering remote surveillance systems, unmanned aerial vehicles)  

Harit Nauka initiative: 

• The ‘Harit Nauka’(green boat) is an initiative of the Ministry of Ports, Shipping and Waterways that envisages a green transition of inland vessels.
• In January 2024, the ministry unveiled the Harit Nauka guidelines for inland vessels. As per the guidelines, all states have to make efforts to use green fuels for 50 per cent of inland waterways-based passenger fleets in the next one decade, and 100 per cent by 2045. This is to reduce greenhouse gas emissions as per the Maritime Amrit Kaal Vision 2047.
  • Globally, the shipping industry is increasingly transitioning to green fuels due to environmental regulations, sustainability goals, and advancements in green fuel technologies.
  •  Hydrogen and its derivatives are gaining attention for promising zero-emission fuels for the industry.