Future of Storage Technology

Research is being conducted on many fronts in the gas storage field to help identify new improved and more economical ways to store gas. Research being conducted by the US Energy department is showing that salt formations can be chilled allowing for more gas to be stored. This will reduce the size of the formation needed to be treated, and have salt extrac- ted from it. This will lead to cheaper development costs for salt formation storage facility type. Another aspect being looked at, are other formations that may hold gas. These include hard rock formations such as granite, in areas where such for- mations exists and other types currently used for gas storage do not. In Sweden a new type of storage facility has been built, called “lined rock cavern”. This storage facility consists of installing a steel tank in a cavern in the rock of a hill and sur- rounding it with concrete. Although the development cost of such facility is quite expensive, its ability to cycle gas multiple times compensates for it, similar to salt formation facilities. Finally, another research projected sponsored by the Depart- ment of Energy, is that of hydrates. Hydrates are compounds formed when natural gas is frozen in the presence of water.

The advantage being that as much as 181 standard cubic feet of natural gas could be stored in a single cubic foot of hydrate.

Safety

Terrorism or deliberate provocation of effusion and inflammation of gas is at this moment the most likely scenario of possible big disaster. Because of this problem America has strictly set the rules that are determining sail with tankers full of LNG. Fast ships are following tanker and protecting it when it sails to terminal and upon cargo unloading. When in sail, tanker cannot be approached by another ship on the distance of 450 meters from each side and 3.2 kilometers in front and behind the ship. For the offenders higher convictions are determined (up to ten years of imprisonment), but that will probably not discourage suicidal terrorists to attempt to crash into a tanker. Legal regulation of the safety is a difficult thing because not even America has completely regulated laws at this moment (for instance, it isn’t completely defined what the coast guard should do if some marine vehicle sails into a safety zone around tankers), and more worrying is the fact that terrorists managed to crash themselves with the craft to a well guarded military ship USS Cole.

The Greenhouse Effect

Pattern of absorption bands created by greenhouse gases in the atmosphere and their effect on both solar radiation and upgoing thermal radiation

When sunlight reaches the surface of the Earth, some of it is absorbed and warms the surface. Because the Earth’s sur- face is much cooler than the sun, it radiates energy at much lon- ger wavelengths than the sun does, peaking in the infrared at about 10 jam. The atmosphere absorbs these longer wave- lengths more effectively than it does the shorter wavelengths from the sun; The absorption of this longwave radiant energy warms the atmosphere; the atmosphere is also warmed by transfer of sensible and latent heat from the surface. Green- house gases also emit longwave radiation both upward to

space and downward to the surface. The downward part of this longwave radiation emitted by the atmosphere is the “green- house effect”. The term is a misnomer though, as this process is not the mechanism that warms greenhouses.

On earth, the most abundant greenhouse gases are, in order of relative abundance:

• water vapor

• carbon dioxide

• methane

• nitrous oxide

• ozone

• CFCs

The most important greenhouse gases are:

• water vapor, which causes about 36-70% of the green- house effect on Earth. (Note clouds typically affect climate differently from other forms of atmospheric water.)

• carbon dioxide, which causes 9-26%

• methane, which causes 4-9%

• ozone, which causes 3-7%

Note that this is a combination of the strength of the green- house effect of the gas and its abundance. For example, methane is a much stronger greenhouse gas than C0₂—about 25 times more heat absorptive, but is present in much smaller concentra- tions.

It is not possible to state that a certain gas causes a certain percentage of the greenhouse effect, because the influences of the various gases are not additive. (The higher ends of the ranges quoted are for the gas alone; the lower ends, for the gas counting overlaps.) Other greenhouse gases include, but are not limited to, nitrous oxide, sulfur hexafluoride, hydroflu- orocarbons, perfluorocarbons and chlorofluorocarbons. A potentially significant greenhouse gas not yet addressed by the IPCC (or the Kyoto Protocol) is nitrogen trifluoride.

The major atmospheric constituents (nitrogen, N₂ and oxy- gen, 0₂) are not greenhouse gases. Nor is the approximately 1% of argon, Ar. This is because homonuclear diatomic molecules such as N₂ and

0₂ and monatomic molecules such as Ar neither absorb nor emit infrared radiation, as there is no net change in the dipole moment of these molecules when they vibrate. Molecular vibrations occur at energies that are of the same magnitude as the energy of the photons on infrared light. Heteronuclear diatomics such as CO or HC1 absorb IR; how- ever, these molecules are short-lived in the atmosphere owing to their reactivity and solubility. As a consequence they do not contribute significantly to the greenhouse effect.

Late 19th century scientists experimentally discovered that N₂ and 0₂ did not absorb infrared radiation (called, at that time, «dark radiation») and that C0₂ and many other gases did absorb such radiation. It was recognized in the early 20th century that the known major greenhouse gases in the atmo- sphere caused the earth’s temperature to be higher than it would have been without the greenhouse gases.