Hydrogen, as energy carrier, can be used either for transport or stationary application s.
Hydrogen in transport
Hydrogen has been used in transport since the Montgolfier brothers invented ballooning back in the late 1700s. Only ten days after their maiden flight using hot air as their lifting gas, a manned hydrogen balloon was launched. Later came a limited use in airships, culminating in the famous Hindenburg disaster. It is worth noting that in these cases hydrogen was not used as fuel for its energy content: instead, it was used because its low density could guarantee the required lift to airships.
Jules Verne was also a keen proponent of hydrogen in his novels: in The Mysterious Island he prophesised the use of water decomposed into its primitive elements (hydrogen and oxygen) as a fuel for the future.
However, it was not until the 1920s and 1930s that uses for hydrogen as an energy carrier were investigated – primarily in vehicle engines but also in fuel cells. Rudolf Erren was a German who converted many truck, car and locomotive engines to run on hydrogen or hydrogen mixtures.
In transport applications, hydrogen can be used both in adapted internal combustion engines and fuel cells.
H 2 internal combustion engines
Hydrogen, like gasoline, diesel and natural gas, burns well in an internal combustion engine. Groups around the world, such as BMW, Mazda and the Musashi Institute of Technology, have successfully designed engines to run on liquid and gaseous hydrogen. While there have been problems with storing the hydrogen and with ensuring that combustion process is smooth, pure hydrogen-using vehicles have been designed and built for over fifty years. In Germany for example, MAN provides pure hydrogen-fuelled buses for cities and airport runways. Each bus is equipped with an engine with power output of 140 kW.
H 2 fuel cells vehicles
Proton Exchange Membrane (PEM) fuel cells (PEMFCs – see relevant section on fuel cells) are the ideal way to convert hydrogen energy into useful power in vehicles. Latest generations of fuel cell vehicles (FCV) have similar or better performances than traditional diesel and the polluting emissions from the exhaust are nothing but water.
Important automotive companies, as DaimlerChrysler (Germany/USA), Ford Motor Company (USA), General Motors (USA), Honda ( Japan), Mitsubishi Motors Corp ( Japan) Peugeot-Citroën ( France), Toyota ( Japan), Volkswagen ( Germany), as well as a number of smaller companies among others, have manufactured around 500 FCV prototypes that are being tested around the world. As to new releases, the past months have seen two major events; the launch of the DaimlerChrysler’s B-Class F-Cell FCV and the General Motors’ Sequel FCV (see Figures below).
DaimlerChrysler’s B-Class F-Cell
The former, which draws on technology from DaimlerChrysler’s agreement with the fuel-cell specialist Ballard, has an improved range of 400 km (an increase of 260 km over the original NECAR) thanks to a decreased fuel consumption and increased onboard hydrogen storage. The GM Sequel has a "skateboard chassis," which means that the liquid hydrogen storage tanks; fuel-cells; by-wire software for steering and brakes; battery packs; and electric motors that power the vehicle are all contained within an 11-inch tall "sandwiched" chassis that protects the components top and bottom.
Hydrogen in stationary applications
Hydrogen for power generation is not being investigated with the same effort and expectations as for transport, except in specific applications.
Under normal circumstances, use of hydrogen purely for electricity generation is currently too expensive, unless exceptional factors such as extreme remoteness are to be considered: in this case, if it becomes more expensive to transport energy through the electricity grid than hydrogen pipeline, then it would make economic sense to generate power from hydrogen at the point of use, using either fuel cells or gas turbines.
In addition, there are other specific situations where the use of hydrogen for power generation could become appealing: for instance, where the prospect of generating high-quality and highly reliable power with no local emissions is appealing, hydrogen could be a premium value proposition for users such as hospitals who require heat and very stable power supplies.
It seems also likely that fuel cell applications will be the first users of hydrogen for power generation, in local areas of byproduct hydrogen such as chemical refineries. However, in urban areas the natural gas fuelled fuel cell will be introduced first, only being replaced by pure hydrogen-fuelled cells when the infrastructure and supply problems have been addressed.
As regards the technology for the use of hydrogen in power generation, two main options are available:
- fuel cells are particularly flexible because they could be produced economically in varying sizes – from about 1 kW to at least 10MW. Fuel cells can therefore cover virtually any size of end use requirement, from in individual homes, large office buildings to industrial facilities
- gas turbines running on hydrogen are likely to be bigger and to require very specialist materials, and as such may only be considered for larger scale power generation.
For further information contact David Hart (email: firstname.lastname@example.org) from E4tech