Bureaucrat, staff, administrator
4,335
edits
Changes
m
→Fuel Cells
There are several [https://en.wikipedia.org/wiki/Fuel_cell fuel-cell technologies] that combine hydrogen and oxygen to produce electricity. The oxygen required for a fuel cell comes directly from the air. The hydrogen is not so readily available. It is difficult to distribute and [https://en.wikipedia.org/wiki/Hydrogen_storage store].
The electricity is used to turn a shaft motor, just like in a diesel-electric system. Current devices the size of a small piece of luggage can [https://www.fueleconomy.gov/feg/fuelcell.shtml power a car]. <ref>Union of Concerned Scientists, http://www.ucsusa.org/clean-vehicles/electric-vehicles/how-do-hydrogen-fuel-cells-work</ref> <ref>Green Car Reports, http://www.greencarreports.com/news/1088626_hydrogen-fuel-cell-cars-to-come-from-toyota-hyundai-honda</ref> As fuel-cell technology improves, fuel cells may well be widespread in marine use. They are already powering submarines and yachts.
However, there are no practical alternatives to diesel fuel for ocean-going boats because of the need to fill up at a fuelling fueling station and store highly compressed (and explosive!) hydrogen.
On the horizon for sea transportation are two promising fuel-cell technologies: Proton Exchange Membrane Fuel Cell (PEMFC) and Direct Methanol Fuel Cell (DMFC).<ref>Center for Renewable Energy & Sustainable technology, http://solstice.crest.org/hydrogen/hydrogen_fuelcell_intro.html</ref> They operate at a fairly low temperature (50-100 °C and 50-200 °C, respectively) compared to other fuel cell technologies, warm up quickly and don't require expensive containment structures.
DMFC fuel cells use a [https://en.wikipedia.org/wiki/Methanol_reformer reformer ] to generate the hydrogen from some other fuel, such as methanol (wood alcohol). Methanol used to be distilled from wood but today is usually processed from natural gas. Methanol is stored at atmospheric pressure, usually in a mild steel tank.<ref>Methanol Institute , http://www.methanol.org/health-and-safety/frequently-asked-questions.aspx</ref>
A basic fuel cell is about 80% efficient at producing electricity. DMFCs are around 40% efficient.<ref>Center for Renewable Energy & Sustainable technology, http://solstice.crest.org/hydrogen/hydrogen_fuelcell_intro.html</ref>
