A chemical cell produces a potential difference until one of the reactants is used up. A hydrogen-oxygen fuel cell uses hydrogen and oxygen, and water is the only product.
In evaluating the use of fuel cellDevice that produces a voltage continuously when supplied with a fuel and oxygen., the following should be considered:
the impact on the environment 鈥 emissionsSubstances that are given off, especially in the form of gas. from the cell as it is used and emissions when the fuel is produced
the impact on the user 鈥 cost, how well it works, how long the fuel cell can run without refuelling, how it compares with existing technology
Advantages of using fuel cells in cars
The use of hydrogen-oxygen fuel cells in cars reduces:
carbon dioxide emissions (because water is the only product)
air pollution where the car is being driven
reliance on fossil fuelNatural, finite fuel formed from the remains of living organisms, eg oil, coal and natural gas.
Disadvantages of using fuel cells in cars
There are disadvantages to using hydrogen-oxygen fuel cells in cars. These include:
hydrogen is in the gas state at room temperature and pressure, so it is difficult to store in the car
fuel cells and electric motors are less durable than petrol engines and diesel engines, so they are not so long-lasting
fuel cells are very expensive
there is no countrywide network of hydrogen filling stations at the moment
some methods of producing the hydrogen fuel release carbon dioxide and other pollutantA toxic chemical or object that causes damage to the land, air or water. into the atmosphereThe layers of gases that surround the Earth. The important gases in the atmosphere are nitrogen, oxygen and carbon dioxide.
There are also safety concerns about the use of hydrogen because it is highly flammable. However, petrol and diesel are also highly flammable.