Posted by: PARTHA DAS SHARMA | May 8, 2009

Hydrogen Fuel Cells

Hydrogen Fuel Cells

A fuel cell is a device that uses hydrogen (or a hydrogen-rich fuel) and oxygen to create an electric current.

The amount of power produced by a fuel cell depends on several factors, including fuel cell type, cell size, the temperature at which it operates, and the pressure at which the gases are supplied to the cell. A single fuel cell produces enough electricity for only the smallest applications. Therefore, to provide the power needed for most applications, individual fuel cells are combined in series into a fuel cell stack.

cell

How a Hydrogen Fuel Cell Works

Hydrogen is contained in almost everything around us, but is rarely found in its pure form. Most of the time, it is bonded with other elements in compounds such as natural gas and water. Hydrogen has to be extracted from these compounds through a manufacturing process that adds energy to break the bonds that hold the compounds together.

A fuel cell is an electrochemical device that splits hydrogen down into its basic components through oxidation and uses those currents, of protons and electrons, to produce electricity. Hydrogen fuel cell technology offers promise of lower-emission engines for industries and automobiles.

Using fuel and oxygen from the air, it produces electricity, water and heat. Water – pure H2O – is the only waste product emitted when hydrogen is used as a fuel in a fuel cell. A fuel cell can generate power almost indefinitely, for as long as fuel is supplied. Plus, a fuel cell is modular and can be scaled up by adding more cells to power everything from cell phones to automobiles to entire buildings.

A hydrogen fuel cell electrochemically combines hydrogen and oxygen to generate electricity, water and heat. There are no other emissions. Different types of fuel cells use different electrolytes with different electrochemical reactions occurring, but the overall reaction is the same. The basic structure of a fuel cell consists of an electrolyte layer in contact with an anode and a cathode.

Typically, fuel is fed continuously to the anode and an oxidant (e.g., oxygen from air) is fed continuously to the cathode. The electrolyte layer acts as a one-way door, allowing either positive or negative ions to travel across, but not electrons, forcing electrons to travel through the external circuit (electric current). This resulting electric current can be used to power electrical appliances.

Uses

Fuel cells have the potential to replace the internal combustion engine in vehicles and provide power for stationary and portable power applications. They can be used in transportation applications, such as powering automobiles, buses, cycles, and other vehicles. Many portable devices can be powered by fuel cells, such as laptop computers and cell phones. They can also be used for stationary applications, such as providing electricity to power homes and businesses.

Benefits

When it comes to converting fuel to power, the fuel cell is two to three times more efficient than the internal combustion engine, which is one reason why every major automobile manufacturer in the world is investing in the development of fuel cells. Fuel cells can offer significant benefits over traditional energy technologies including:

* Superior fuel efficiency,

* Hydrogen Fuel Cells are cleaner and have zero to near-zero emissions in comparison to combustion engines,

* Versatility – hydrogen fuel cells can be applied in micro, portable, stationary, and transportation applications,

* Low maintenance costs, due to few moving parts,

* Modular design allowing for low cost high volume manufacturing,

* Design freedoms and,

* Quiet operation.

If hydrogen is produced in a sustainable way using renewable energy, then hydrogen fuel cell technologies can provide a sustainable source of energy.

Conclusion

Fuel cells have been around since 1839, but it has taken many years for us to understand the range and value of their potential applications. Today, with the support of governments and the private sector, hundreds of companies worldwide are working towards making fuel cell technology a reality. Similar to the commercialization of the electric light bulb nearly one hundred years ago, today’s companies, government departments and end user organizations are driven by technical, economic and social forces to make the hydrogen fuel cell part of our everyday lives.

Hydrogen Fuel Cells – Science Terminology

* Anode: the negatively charged terminal of an energy cell or storage battery,

* Cathode: the positively charged terminal of an energy cell or storage battery,

* Proton: a positively charged hydrogen ion,

* Electron: a negatively charged sub-atomic particle,

* Electrolyte: a chemical compound that allows conduction of ions, but not electrons,

* Electrochemical Conversion: an electrochemical process that converts chemical energy to electrical energy


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