Monday, October 20, 2008

Hydrogen – Fuel of the future?

Many energy experts speak of hydrogen as the fuel of the future. Hydrogen already has number of industrial uses and has potential to one day replace fossil fuels to power vehicles without emitting harmful carbon dioxide responsible for global warming. There is one problem though, namely finding an environmentally friendly way to produce hydrogen in large quantities because current production methods include production of hydrogen by splitting methane. This is of course environmentally unacceptable because this process uses highly harmful methane and it also creates carbon dioxide as a byproduct.

Many research projects have been carried out with the purpose to find more cleaner way to produce hydrogen, and the latest one is located in Idaho, where Idaho National Laboratory plans to develop environmentally friendly process by splitting steam into hydrogen and oxygen with the help of high-temperature electrolysis, where high-temperature electrolysis would use heat to generate hydrogen, without producing carbon dioxide.

"Zero emission, low noise, high energy-efficiency… this is like a dream." said an excited passenger on board a hydrogen fuel cell bus (Beijing Hydrogen Park).

Researchers already completed first test with positive results and their facilities should be working with a full capacity later this year, enabling production of roughly 500 grams of hydrogen per hour. This doesn’t seem that much but scientists are already working on a full-scale hydrogen plant that should be capable to produce two-and-a-half kilograms of hydrogen each second. Just for comparison between measures, when speaking about the cars one kilogram of hydrogen contains roughly the same amount of energy as a gallon of gasoline.

However this is not easy to achieve, especially finding the right components that operate well on high temperatures. This is the reason why researchers use fuel cell-like materials that operate well on high temperatures. This is done by help of many solid oxide cells, where in each oxide cell, a high voltage pulls oxygen ions through a ceramic electrolyte, effectively separating the steam into hydrogen and oxygen.

The biggest challenge the team will be facing is to make solid oxide cells capable to resist corrosion. Constant use in a difficult, high-temperature environment quickly reduces efficiency of the cells that has negative impact on hydrogen production. The team has so far tested stacks of cells that have operated for as many as 2,000 hours, or three months. But commercial high-temperature electrolysis plant that would be cost-effective should have cells capable to run for at least two years.

One way to produce hydrogen using high temperature electrolysis. In this case heat from a nuclear reactor is used as input in heat exchanger, but in general case one can use any source of high temperature. Click on picture to enlarge.

It is very obvious that conversion to a hydrogen-based energy economy will take many decades, but these researches are good starting point that should set the standards for years to come. These projects are still not economically acceptable to be used on large scale but one solution leads to another, and given more funds these projects could prove to be excellent alternative to dominant fossil fuels.

Once hydrogen projects like this one become cost-effective there will have many advantages compared to fossil fuels use, most importantly their ecological advantage, by being more environmentally friendly than fossil fuels. Fossil fuels when burning create CO2, greenhouse gas mainly responsible for climate change and global warming, and these new hydrogen projects are meant to be without CO2 as byproduct.

What these new alternative energy projects needs the most are funds and political support. Fossil fuels, despite recent climate change problems, still have very strong lobbies, and they still are going to remain dominant energy source in years to come. Hydrogen as well as some other alternative fuels looks to be having bright energetic future, there are already some that say how hydrogen will become dominant fuel to power vehicles in years to come. However there is still lot of research left to do before hydrogen's "future potential" becomes obvious.

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