A fuel cell uses the chemical energy of hydrogen or another fuel to cleanly and efficiently produce electricity. If hydrogen is the fuel, electricity, water, and heat are the only products. Fuel cells are unique in terms of the variety of their potential applications; they can provide power for systems as large as a utility power station and as small as a laptop computer.
Working of Fuel cell:
Fuel cells work like batteries, but they do not run down or need recharging. They produce electricity and heat as long as fuel is supplied. A fuel cell consists of two electrodes—a negative electrode (or anode) and a positive electrode (or cathode)—sandwiched around an electrolyte. A fuel, such as hydrogen, is fed to the anode, and air is fed to the cathode. In a hydrogen fuel cell, a catalyst at the anode separates hydrogen molecules into protons and electrons, which take different paths to the cathode. The electrons go through an external circuit, creating a flow of electricity. The protons migrate through the electrolyte to the cathode, where they unite with oxygen and the electrons to produce water and heat.
Fuel cells have various advantages compared to conventional power sources, such as internal combustion engines or batteries. Although some of the fuel cells’ attributes are only valid for some applications, most advantages are more general.
Benefits of fuel cell:
- Fuel cells have a higher efficiency than diesel or gas engines.
- Most fuel cells operate silently, compared to internal combustion engines. They are therefore ideally suited for use within buildings such as
- Fuel cells can eliminate pollution caused by burning fossil fuels; for hydrogen fuelled fuel cells, the only by-product at point of use is water.
- If the hydrogen comes from the electrolysis of water driven by renewable energy, then using fuel cells eliminates greenhouse gases over the whole
- Fuel cells do not need conventional fuels such as oil or gas and can therefore reduce economic dependence on oil producing countries, creating greater energy security for the user nation.
- Since hydrogen can be produced anywhere where there is water and a source of power, generation of fuel can be distributed and does not have to be grid-dependent.
- The use of stationary fuel cells to generate power at the point of use allows for a decentralised power grid that is potentially more stable.
- Low temperature fuel cells (PEMFC, DMFC) have low heat transmission which makes them ideal for military applications.
- Higher temperature fuel cells produce high-grade process heat along with electricity and are well suited to cogeneration applications (such as combined heat and power for residential use).
- Operating times are much longer than with batteries, since doubling the operating time needs only doubling the amount of fuel and not the doubling of the capacity of the unit itself.
- Unlike batteries, fuel cells have no “memory effect” when they are getting refuelled.
- The maintenance of fuel cells is simple since there are few moving parts in the system.
