FUEL CELL TECHNOLOGY
Operation principles
- Fuel cells are highly efficient power-generating systems that produce electricity by combining fuel (hydrogen) and oxygen in an electrochemical reaction or fuel cells are electrochemical devices that convert the chemical energy of a fuel directly and very efficiently into electricity (DC) and heat, thus doing away with combustion.
Components & reactions
- Hydrogen and phosphoric acid are the most common type of fuel cells, although fuel cells that run on methanol, ethanol, and natural gas are also available. The most suitable fuel for such cells is hydrogen or a mixture of compounds containing hydrogen. A fuel cell consists of an electrolyte sandwiched between two electrodes. Oxygen passes over one electrode and hydrogen over the other, and they react electrochemically to generate electricity, water, and heat. Traditional methods generating electricity require combustion of fuel and the resultant heat is used to produce steam to run turbines which generate electricity. This method involves loss of heat and thus not very efficient. In chemical fuel cells on the other hand, chemical energy is converted directly into electricity, thus are more efficient and do not produce harmful gases.
Basic components of a hydrogen-burning fuel cell
- Both oxygen and hydrogen are added to the fuel cell in an electrolyte solution. The reactants remain separated from one another and, upon ionization, migrate through the electrolyte solution from one electrode to another. The flow of electrons from the negative to the positive electrode is diverted along its path into an electrical motor, supplying current to keep the motor running. In order to maintain this reaction, hydrogen and oxygen are added as needed. Waste products are only oxygen and water when hydrogen is used in a fuel cell. Using natural gas methane (CH4 ) in fuel cells produces some pollutants, but the amount is only about 1% of what would be produced by burning fossil fuels in an internal combustion engine or a conventional power plant.
Advantages over combustion
- Additionally, the efficiency of a fuel cell is largely independent of its size and energy output. For these reasons, fuel cells are well-suited for automobiles, homes, and large-scale power plants. They can also be used to store energy to be used as needed. Fuel cells are in use particularly in Canada’s Ballad’s Power Systems in Canada and Germany’s Dailmer-Benz in Germany are world leaders in the application of fuel cell technology for meeting transportation needs. Such buses are already in operation in Vancouver in Canada and in Illinois in USA. Though rapid progress has been made; high initial cost is still the biggest hurdle in the widespread commercialization of fuel cells.
Fuel cell technology in India
- Fuel cell systems are excellent options for small-scale decentralized power generation. Fuel cells can supply combined heat and power to buildings, hospitals, airports and military installations at remote locations. Fuel cells have efficiency levels up to 55% as compared to 35% of conventional power plants. The emission of green house gases is significantly low CO2 as water vapor is being the only emission. Fuel cell systems are modular (i.e. additional capacity can be added whenever required with relative ease) and can be set up wherever power is required.
Fuel cell technology and environment
- Fuel cells are efficient and clean energy producer. Fuel cells have been used in space flights and being introduced in electric vehicles for reducing urban air pollution. Compared to vehicles powered by the internal combustion engine, fuel cell powered vehicles have very high-energy conversion efficiency, (almost double that of currently used engines) and near-zero pollution. Fuel-cell-powered EV’s (electric vehicles) score over battery operated EV’s in terms of increased efficiency and easier and faster refuelling.