Hydrogen Benefits
Reduce Greenhouse Gas Emissions
Greenhouse gases are thought to be responsible for changes in global climate. They trap excess heat from the sun's infrared radiation that would otherwise escape into space, much like a greenhouse is used to trap heat. When we drive our cars, and light, heat, and cool our homes, we generate greenhouse gases. But if we used hydrogen in very high efficiency fuel cells for our transportation and to generate power, we could significantly reduce the GHG emissions - especially if the hydrogen is produced using renewable resources, nuclear power, or clean fossil technologies.
Reduce Air Pollution
The combustion of fossil fuels by electric power plants, vehicles, and other sources is responsible for most of the smog and harmful particulates in the air. Fuel cells powered by pure hydrogen emit no harmful pollutants. Fuel cells that use a reformer to convert fuels such as natural gas, methanol, or gasoline to hydrogen do emit small amounts of air pollutants such as carbon monoxide (CO), although it is much less than the amount produced by the combustion of fossil fuels.
Huge oil spills are becoming very common, killing all sorts of aquatic life. If hydrogen fuel were spilled in large quantities it would evaporate instantaneously and the only by-product of hydrogen fuel is water.
Changing to a hydrogen-based economy would create thousands of new industrial and scientific jobs. Building plants, manufacturing parts and selling equipment would all be investments that stimulate jobs and growth.
Fossil fuels will eventually run dry. Hydrogen is renewable, therefore it's unlimited.
Hydrogen is the ideal alternative fuel as it offers many benefits; there are two drawbacks to using it as a fuel with current technology. Liquid hydrogen, the preferred form of hydrogen, requires four times the storage space of conventional petroleum-based fuels. The other problem is that hydrogen production depends on the availability of a non-renewable resource, petroleum. Currently, hydrogen is produced from raw petroleum for industrial use, but petroleum supplies may become limited in the near future.
Storage
Hydrogen may be stored on platforms using a variety of technologies. At room temperature, hydrogen is a gas that can be stored in compressed gas cylinders similar to those used on natural-gas-powered vehicles. Gaseous fuels contain comparatively little energy per unit volume, so platforms using gaseous hydrogen may have a somewhat reduced range compared to platforms using liquid fuels such as gasoline or diesel. Hydrogen also may be stored in liquid form, but it becomes a liquid only at very low temperatures, so special fuel tanks are necessary to keep the hydrogen cold and prevent losses. Liquid hydrogen storage is preferred to compressed gas storage since more hydrogen can be stored in the liquid state than in the gaseous state.
Transport
Both compressed gaseous hydrogen and liquid hydrogen can be transported by trucks or rail. Liquid hydrogen can be transported in pressurized tanks by truck, rail, barge, or ship. Insulation of the storage tanks is of utmost importance. Due to the very low boiling point of hydrogen, losses resulting from boil-off can be considerable. Pressurized hydrogen gas can be transported via pipelines.
Safety
The safety of any energy source is always a concern. AAN platforms must be engineered properly to minimize risks to their crews. Although hydrogen has different characteristics from petroleum-based fuels, it is as safe as gasoline, diesel, or kerosene.
Hydrogen's explosive range is a 13- to 79-percent concentration in air. It is colourless and odourless and burns with a nearly invisible flame. Hydrogen's wide explosive range, coupled with its very low ignition energy, give it a potential disadvantage since an accumulation of hydrogen in a poorly ventilated vehicle interior may explode easily.
The minimum ignition energy required to ignite a hydrogen mixture is 0.02 mill joules, which is equal to the energy of a static electric discharge from the arcing of a spark. However, the vapours of petroleum-based fuels ignite just as easily.
The diffusion coefficient for hydrogen is 0.61 cubic centimetres per second (cm3/sec), which means that hydrogen mixes with air faster than does gasoline vapour. Hydrogen's low vapour density and high diffusion coefficient cause it to rise quickly, so that in the open, hydrogen mixes with air and disperses rapidly with no pooling on the ground—unlike petroleum-based fuels.
Since there is a possibility that hydrogen might leak into the crew compartment, hydrogen detectors must be used aboard platforms to detect explosive concentrations of hydrogen. A ventilation system could be used to exhaust the explosive mixture to the atmosphere. Also, since hydrogen's ignition energy is extremely low, a sparkless environment must be provided. The sparkless environment should include an extremely well-insulated electrical system and some form of grounding for the crew so they do not build up a static charge during platform operation.
Environmental Considerations
Hydrogen is the cleanest fuel available. Hydrogen-fuelled ICE's and gas turbine engines have negligible emissions of air pollutants. Hydrogen-powered-fuel-cell vehicles have zero emissions. On the other hand, platforms powered by petroleum-based fuels emit significant amounts of air pollutants (hydrocarbons, carbon monoxide, nitrogen oxides, sulphur oxides, and particulate matter), air toxics (either confirmed or suspected human carcinogens, including benzene, formaldehyde, 1,3-butadiene, and acetaldehyde), and carbon dioxide. The health effects of these pollutants range from headaches to serious respiratory damage such as lung cancer.
Burning hydrogen with air under appropriate conditions in ICE's or gas turbines results in very low emissions. Trace hydrocarbon and carbon monoxide emissions, if generated at all, can result only from the combustion of motor oil in the combustion chamber of ICE's. Nitrogen oxides (NOx) emissions increase exponentially with the combustion temperature. Therefore, these can be influenced through appropriate process control. Using hydrogen in fuel cell propulsion systems with low temperature fuel cells completely eliminates all polluting emissions. The only byproduct resulting from the generation of electricity from hydrogen and atmospheric oxygen is water.
Hydrogen has a higher energy density than petroleum-based fuels. It supplies more energy per unit volume than gasoline, diesel, or kerosene. Hydrogen is extremely abundant. Research and development projects have demonstrated that using compressed hydrogen or liquid hydrogen as a fuel for ICE's, gas turbine engines, or fuel cells is feasible today. Further research is needed to increase the power outputs from the ICE's and gas turbine engines.
less energy per volume compared to liquid fuels like gasoline or ethanol. Hydrogen can also be cooled to produce liquid hydrogen, but it is costly.
Hydrogen's clean burning characteristics may, one day, make it a popular transportation fuel. For now, the problem of how to store enough hydrogen on a vehicle for a reasonable range, and its high cost, compared to gasoline, are critical barriers to widespread commercial use.
Nearly all hydrogen currently is made from natural gas. For that reason, hydrogen usually costs more than natural gas.
Hydrogen fuelled vehicles
There have only been a small number of prototype hydrogen vehicles made. Most of these have been experimental vehicles made by car manufacturers. Nearly all of these prototype cars were equipped with internal combustion engines, similar to ones that run on gasoline.
