Introduction to Fuel Cells

Fuel cells are energy conversion devices which convert the chemical energy in a fuel directly into electricity and heat.
They are different from regular batteries, as they require a continuous source of fuel and oxygen to operate, but they create energy as long as these inputs are supplied.

Principle of Operation

Fuel cells consist of an anode, a cathode, and an electrolyte.
The fuel, typically hydrogen, is fed into the anode where it is oxidised, releasing electrons and producing positively-charged hydrogen ions.
The electrolyte only allows the passage of these ions from the anode to the cathode. The electrons instead travel via an external circuit, producing an electric current.
At the cathode, oxygen from the air combines with the electrons and hydrogen ions to produce water, the only waste product.

There are several types of fuel cells, including Proton Exchange Membrane Fuel Cells (PEMFC), Alkaline Fuel Cells (AFC) and Solid Oxide Fuel Cells (SOFC).
They each have different operating temperatures, efficiencies and suitable applications.

Fuel cells are highly efficient and cause less pollution as the waste product is usually just water. Hence, they offer a sustainable energy solution.
They can be used in a wide range of applications including vehicles (cars, buses), portable devices and stationary power generation.

Challenges for fuel cell technology include high cost, durability, energy efficiency and the availability of hydrogen.
Currently, the production of hydrogen is mostly from natural gas, which involves carbon emissions. Hence, until renewable sources of hydrogen are commercially viable, fuel cells cannot be considered completely ‘green’.

Similar to other energy systems, fuel cells require safe handling and operation. This includes ensuring the hydrogen is stored and transported safely due to its highly flammable nature.