There is a lot of hype right now about hydrogen fuel and its possible uses. The technology is no longer theory; we are seeing in action. Unfortunately it could still be 10 – 20 years before we see this technology in abundance.
Many people look past the obstacles too easily, simply hoping for the prize at the end: clean, renewable, cost efficient energy. The main obstacles to overcome are storage, production, and use in vehicles.
Technology is coming along, but the storage of hydrogen is still very difficult. Since it is a gas at normal temperatures, hydrogen would have to be stored in pressurized tanks, if it were in gaseous form. Retaining enough fuel to provide a car with sufficient range would require that the tanks be under immense pressure (greater than can be obtained currently).
At present, practical hydrogen storage tanks are providing 100 – 150 miles to a tank of gas. To increase that number, researchers have investigated liquid hydrogen storage. In liquid form, the hydrogen would be more dense and able to hold more energy per unit volume. The ability to to maintain liquid hydrogen on a vehicle is still questionable however.
On top of storage, the future of mass produced hydrogen is unsure. Since hydrogen cannot be harvested from the air, it has to be extracted from compounds on earth. The two main processes for harvesting are methane extraction and electrolysis. Methane extraction is currently the most common way to obtain hydrogen, but experts believe that electrolysis will prevail in the future.
Electrolysis works by splitting water molecules in to H2 and O2 gasses by using electricity. Right now the process requires so much electricity, that it is not even practical to use on a large scale.
Even still, there are two types of hydrogen vehicles that people still clump into one. There is a hydrogen internal combustion engine and a hydrogen fuel cell powered vehicle. The two types of technology are quite different. Vehicles powered by fuel cells are still very far off. The technology is still extremely expensive, but as technology improve and prices come down, these vehicles will be the cleanest and most efficient.
Right now the first option is much more likely, however. An internal combustion engine can run on hydrogen with only a few simple modifications. As soon as hydrogen can be produced and stored on a large scale, we will certainly see these types of vehicles on the road.
Despite all the negative aspects of hydrogen fuel technology, much research is going on, and progress is being made daily. By weight, hydrogen fuel caries more energy than gasoline, so it is a logical move to raise awareness in hopes of using it some day. Maybe most importantly, hydrogen could reduce prices at the pump by as much as 50%. It might be a ways off, but anything that can save us $$$ is OK by us!