Gasoline

As noted above, while gasoline is currently being considered for on-board reformation, we are only considering its viability as a off-board reformation fuel. Reforming hydrogen from gasoline (the chains from C7H16 through C11H24 are blended together and used for gasoline) is very energy intensive and produces CO2 as a byproduct, along with other toxins. This lessens its overall value as an greenhouse gas reducer, and the energy needed to reform it will cut back on the overall efficiency of a fuel cell. Also, using gasoline for hydrogen does not promote energy independence. The biggest benefit to using gasoline as a hydrogen source is that it is the dominant fueling infrastructure in the developed world. Using gasoline would avoid the prohibitive expense of developing a new infrastructures.

Compressed natural gas (CNG)

Compressed natural gas (CH4) is also known as methane. CNG has high hydrogen content and is relatively inexpensive. CNG requires less energy than gasoline to extract the hydrogen, but is not as ubiquitous as gasoline for refueling infrastructure. Like gasoline reformation, CNG reformation produces CO2, which is a greenhouse gas. Methane is a potent greenhouse gas, so any venting of the CNG would mean significant greenhouse gas emissions associated with CNG reformation. If the CNG is reformed at the wellhead, with the hydrogen then transported to the refueling site, the CO2 can be sequestered at the wellhead.

An advantage of using CNG is its availability, and the fact that it is a mature industry. The negatives are that it requires greater safety training and handling than gasoline; this could be improved with hydrogen reformation technology. Most industrial hydrogen used today comes from the oil wellhead off CNG.

Sunline Transit is using hydrogen reformed from CNG on-site at its refueling facility for its fuel cell bus demonstration program (along with other hydrogen production methods). Because Sunline Transit employs CNG buses in its regular fleet, it has an existing CNG distribution system that it can take advantage of for its fuel cell buses.

Ethanol

Ethanol can be made from any starch or sugar source, although it can also be produced chemically from ethylene, a component of natural gas. Ninety percent of ethanol production in the U.S. is from corn, consuming approximately six percent of the nationÕs crop. Other feedstock sources include other grains, cheese whey, potatoes, sugar cane and rice straw.

The drawbacks of e ethanol are not as simple as methanol to reform into hydrogen, and, most importantly, it is expensive to produce.

An advantage of ethanol use is that ethanol production facilities are modular, meaning that expansion can be constructed quickly and to meet increasing demand over time. It also means that production facilities face little economies of scale in production making small facilities as competitive as large ones.

Another advantage of ethanol is that, because it can be made from a variety of feedstocks, it is adaptable to whatever feedstocks are most appropriate for the region producing the ethanol.

Methanol

Methanol reformation is the simplest of the fossil fuels. It produces lower emissions and a higher concentration of hydrogen. However, it needs to be produced from another source, for example natural gas, which makes it less efficient. In addition, in order for methanol to be transported across gas pipelines and stored at gas refueling sites, a significant infrastructure upgrade would have to be made. While methanol is begin considered for onboard reformation, because of the advanced stage of development of this technology, it is unlikely to be used as a fuel source at hydrogen reformation sites.

Back to main fuel cell bus page