Fuel Cell Technology

- Overview

Fuel cells use the chemical energy of hydrogen or other fuels to generate electricity cleanly and efficiently. If hydrogen were the fuel, the only products would be electricity, water and heat. 

Fuel cells can be used in a wide range of applications to provide power for applications in multiple sectors, including transportation, industrial/commercial/residential buildings, and long-term energy storage for the grid in reversible systems.

- Advantages of Fuel Cells

Fuel cells offer several advantages over conventional combustion technologies currently used in many power plants and vehicles. 

Fuel cells operate more efficiently than internal combustion engines and can directly convert chemical energy in fuel into electrical energy with an efficiency of more than 60%. 

Fuel cells have low or zero emissions compared to internal combustion engines. Hydrogen fuel cells emit only water and, because they emit no carbon dioxide, could solve serious climate challenges. 

The operation site is also free of air pollutants that create smoke and cause health problems. Fuel cells are extremely quiet during operation because they have few moving parts.

- Hydrogen Energy

Hydrogen is a clean fuel that produces only water when consumed in fuel cells. Hydrogen can be produced from a variety of domestic sources, such as natural gas, nuclear energy, biomass, and renewable energy sources such as solar and wind. 

These qualities make it an attractive fuel option in transportation and power generation applications. It can be used in cars, homes, portable power supplies, and many more applications. 

Hydrogen is an energy carrier that can be used to store, move and deliver energy generated from other sources. Today, hydrogen fuel can be produced through a variety of methods. The most common methods today are natural gas reforming (heat treatment) and electrolysis. Other methods include solar drives and biological processes.

- How Fuel Cell Works

A fuel cell is a device that generates electricity through an electrochemical reaction, not combustion. In a fuel cell, hydrogen and oxygen are combined to generate electricity, heat, and water. Fuel cells are used today in a range of applications, from providing power to homes and businesses, keeping critical facilities like hospitals, grocery stores, and data centers up and running, and moving a variety of vehicles including cars, buses, trucks, forklifts, trains, and more. 

Fuel cell systems are a clean, efficient, reliable, and quiet source of power. Fuel cells do not need to be periodically recharged like batteries, but instead continue to produce electricity as long as a fuel source is provided. 

A fuel cell is composed of an anode, cathode, and an electrolyte membrane. A typical fuel cell works by passing hydrogen through the anode of a fuel cell and oxygen through the cathode. At the anode site, a catalyst splits the hydrogen molecules into electrons and protons. The protons pass through the porous electrolyte membrane, while the electrons are forced through a circuit, generating an electric current and excess heat. 

At the cathode, the protons, electrons, and oxygen combine to produce water molecules. As there are no moving parts, fuel cells operate silently and with extremely high reliability.

- Anodes and Cathodes

Anodes and cathodes are two electrodes that facilitate the flow of electric charge in batteries and electrochemical cells. The anode is the negative electrode, where oxidation (loss of electrons) takes place. The cathode is the positive electrode, where reduction (gain of electrons) occurs. 

Anodes and cathodes have the following characteristics:

• Anode: The negative electrode where electricity moves into. It releases electrons to the external circuit and oxidizes during an electrochemical reaction.
• Cathode: The positive electrode where electricity is given out or flows out. It acquires electrons from the external circuit and is reduced during an electrochemical reaction.

- Types of Fuel Cells

Although the basic operation of all fuel cells is the same, special varieties have been developed to utilize different electrolytes and meet different application needs. The fuel and charged species migrating through the electrolyte may be different, but the principle is the same. Oxidation occurs at the anode, while reduction occurs at the cathode. 

The two reactions are connected by the migration of charged species through the electrolyte and the flow of electrons through an external circuit.

• Polymer electrolyte membrane fuel cell
• Direct methanol fuel cell
• Alkaline fuel cells
• Phosphoric acid fuel cells
• Molten carbonate fuel cells
• Solid oxide fuel cells
• Combined heat and power fuel cells
• Regenerative or reversible fuel cell

[More to come ...]