Polymath A (mostly) technical weblog for Archivale.com

August 6, 2010

The Helium Question

Filed under: Aeronautics,Engineering,Lighter than Air,Materials — piolenc @ 11:21 pm

[This piece first appeared in the Fall/Winter 2006 issue of Aerostation magazine]

LTA: 2006 and the Helium Question

The year 2006 was much the same as any other recent year, at least as far as lighter-than-air flight is concerned. Hopes were raised, then dashed. Projects were mooted, then cancelled. Brave talk was uttered, then swallowed.

If Ought Six is remembered for anything, perhaps it will be that the first visible cracks appeared in the ever-rickety edifice of helium supply. For the first time that I can recall, some users of helium were told that they could not have any at any price, due to the fact that one of the world’s few helium extraction plants was undergoing refurbishment. Presumably extraction has since resumed—there are no panic-stricken “Brother, can you spare some gas?” posts on the LTA-related lists—but this little hiccup is a harbinger of things to come.

Those of you who have followed my rants over the years may want to skip the rest of this piece, but some points deserve to be reviewed. As commodities go, helium is extremely unusual—perhaps unique. It is a by-product of the extraction of another commodity—natural gas—whose unit value is much lower, but whose aggregate value is orders of magnitude greater. This means that the usual assumptions about supply and demand do not apply.

To make it clear why this is so, imagine a commodity—say, a precious metal—that exists in a concentration of a fraction of a percent in a matrix that has no market value. If the market value of the metal justifies it, somebody will extract the tiny metal moiety from the huge mass of matrix, refine and market the metal and dispose of the now completely valueless matrix. The key fact is that, in this hypothetical but typical case, the extraction is driven solely by the market for the metal. If the market value of the metal drops below the cost of bringing it to market, extraction ceases and the metal remains in the ground, in its matrix, waiting for changing conditions to again make it profitable to exploit it.
Contrast this with what will happen if there is a significant increase in demand for helium. Helium, as we know, exists as a tiny fraction of natural gas; some deposits contain more helium than others, and gas from some of those favored deposits passes through a helium-extraction plant on its way to market. The helium in natural gas that is produced without extracting the helium is gone forever, wasted.

Now suppose that there is an increase in demand for helium. Once stored helium stock is exhausted, the only way to meet the greater helium demand is to increase the production of natural gas. This may be done, up to the point that storage capacity for natural gas awaiting delivery to consumers is completely used up. At that point, helium production is capped at a rate proportional to the current demand for natural gas, irrespective of demand for helium. Nobody is going to flare off natural gas to accommodate helium users!

Now the operation of a free market, when production of a commodity is fixed and demand for it increasing, is to raise prices until demand drops to match the supply. This gives a bidding advantage to users who are well-funded and use relatively small quantities of helium. LTA doesn’t match that description, and never will. But there’s worse.

Another effect of a free market is that rising prices of a commodity encourage capital to move into production of that commodity, leading to increased capacity, which in turn tends to put the brakes on price increases. Can we expect this to happen with helium? One can imagine that, with helium prices skyrocketing, producers of natural gas from fields less favored by Nature than those now being exploited might install helium extraction plants at their fields, thus intercepting streams of helium now going up the stack. And then again, maybe not. Helium extraction is capital-intensive—essentially, it requires that all gases except helium be liquefied, leaving only helium in gaseous form. Depending on the projected exhaustion of the field, the helium concentration in the gas and their estimate of the persistence of increased demand, the field’s exploiters may or may not feel that they can expect an adequate return on their investment in new helium plant. Even assuming that the answer is always affirmative, there is a definite physical limit to this capacity increase, which is imposed by the rate of production of natural gas. What is more, each increment of production will be smaller than the last and cost more per unit of capacity, as poorer fields are added to the helium production stream.

The best scenario that we can expect, then, in the event of a true rebirth of helium-based LTA, is a steady rise in price, possibly restrained (but not cancelled) by capacity increases. It is a safe bet, however, that any major increase in helium demand will run up against a hard capacity limit, whether imposed by the reluctance of field exploiters to install expensive helium extraction or by the finite and tiny concentration of helium present in the natural gas stream.
When such an absolute limit is reached, modern governments show a deep reluctance to let market forces operate. Instead, rationing and price controls are imposed and favored users are given priority for supply. In the USA, at least, there is no doubt of LTA’s position in the hierarchy of government favor: near bottom, perhaps just one step above party balloons, perhaps even one step below (what would a political campaign be without balloons, eh?).

In the long run, the Earth’s supply of helium will be exhausted when we run out of natural gas, regardless of the level of demand for helium. Helium is the end product of a long chain of radioactive decay, and for practical purposes “they ain’t makin’ any more of it.”

Of course, I’ve been oversimplifying, by assuming that a revival of large-scale helium LTA would occur in the first place. In fact, no prudent investor would invest in commercial helium-lift LTA without considering the prospects for gas supply, and with the certainty of price increases and the uncertainty of future supply at any price, he will put his money elsewhere.

The plain fact is that helium is already too expensive. Its 6% gross lift penalty compared to hydrogen comes directly out of useful lift, imposing a net penalty around 20% depending on payload ratio. Its cost constrains airship operations by limiting operating altitude or fullness (hence lift) to avoid valving gas and by forcing operators to operate at very low purity to delay “shooting” gas as long as possible. Both constraints further reduce the economic viability of an already marginal transport medium.

If large-scale LTA is to survive, there will have to be a transition to hydrogen as the lifting gas. The only question that is open is: when? If LTA is ever to be used for transport of goods or people, that revival will have to be based on hydrogen lift. And it must be soon.

The time to prepare the transition is now, while there are people still living who have handled hydrogen in an LTA context, and who can instruct others. Hydrogen is more dangerous than helium, but there is no alternative. There are obstacles to be overcome in using it, and the sooner we start overcoming them the sooner we will have viable commercial LTA. The principal obstacles are:

• Lack of trained personnel.  Solution: train some.

• Lack of insurance cover.  Solution: insurance companies will ensure anything for which they have reliable actuarial statistics. Only experience can produce those statistics. Until they are available, operators will have to self-insure. It has been done before, and it can be done again.

• Government regulations and statutes.  Solution: a stroke of a pen.

Hindenburg Syndrome.  Solution: education and exposure.

Priced out of the market, or forced out. Those are the only possible fates of LTA if we persist in considering only helium as a lifting gas. It is, in the current jargon, unsustainable.


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