Scientists, governments and activist groups have been advocating alternative fuels for decades. In recent years, several options have emerged for powering car without using fossil fuels. Along with hybrid-electric and all-electric vehicles, hydrogen fuel cell systems are a popular subject of discussion. However, hydrogen has both distinct advantages and disadvantages as a fuel.

One of the primary advantages of hydrogen as a fuel is its abundance. In fact, hydrogen is the most abundant element on Earth. It can be extracted from natural gas or water and is present in a number of other chemical compounds. Hydrogen is also an element and can't be destroyed (only recombined with other elements), meaning that the world's supply will never be exhausted, as with fossil fuels.

When hydrogen cycles through a fuel cell to create electricity that will power a car, its only byproducts are heat and water. This is another major advantage over fossil fuels, which create harmful carbon emissions when burned.

One key disadvantage to hydrogen fuel is the difficulty storing it. Hydrogen needs to be kept under strong compression to be a viable fuel source, necessitating strong tanks and heavy-duty fueling lines. As there is currently no mainstream system of storage and distribution for hydrogen fuel, this is a major practical disadvantage.

Hydrogen is also expensive to produce in sufficient quantities using today's technology. More inexpensive methods extract hydrogen at high energy costs, negating any energy savings that come from avoiding gasoline for fuel in the car. For hydrogen to become competitive, researchers will need to find new, more efficient and cost-effective ways to produce large amounts of hydrogen.

Hydrogen is a very efficient fuel source, capable of producing more energy per pound of fuel than gasoline. This means that an equal-sized tank of hydrogen fuel would give a vehicle a greater range or more power than when filled with gasoline and an internal combustion engine. This advantage is especially relevant in the face of batteries on electric vehicles that may limit the car's range to less than 100 miles, making it impractical for some drivers.