The Coldest Liquid

Most of us link helium with airships, blimps, and balloons, for in their heyday these gave spectacular evidence of two unusual characteristics the gas. Helium is light—almost as light as hydrogen—and it is inert and therefore will not ignite. The disastrous explosions of hydrogen-filled airships in the thirties, followed in this country by the swift substitution of helium for hydrogen as a lifting gas, established this unique combination of properties in our minds so well that it is hard to realize that this use now accounts for only about 5 percent of annual helium consumption.

Today, helium's other unusual properties are being utilized. This gas conducts heat and electricity better that most metals; it transmits light with less distortion than any other element; its molecule is so small and symmetrical that it will pass rapidly through openings that would delay other gases for weeks. And, perhaps most important for future applications, helium, which does not even liquefy until minus 452 degrees Fahrenheit, is the only element that remains liquid at absolute zero (minus 459 degrees F.), the temperature at which projectile motion theoretically ceases. This last-named property has permitted development of the new field of physics, cryogenics or low-temperature research. At deep cold temperatures not only can subatomic particles whose normal life is measured in microseconds, be preserved indefinitely, but also common materials take on radically different properties. To choose only one example, some metals become superconductors offering zero resistance to the passage of electric current. Already this property has been used to design a computer that can be held in two hands.

When helium was used exclusively as a lifting gas, annual peacetime consumption seldom exceeded 20 or 30 million cubic feet. But it was not long after the close of World War II that scientific and industrial applications for helium started consumption spiralling upward at the rate of nearly 20 percent per year. By 1960 the consumption of helium in the United States had reached 475 million cubic feet, more than cumulative consumption for all years up to 1945; and by 1964 consumption had grown to 713 million cubic feet.

With use growing at such a rate, the question arises: Is our supply exhaustible? The supply of low-cost helium certainly is exhaustible. Helium in the earth is produced by the radioactive decay of uranium and a few other elements. It is so light that it ordinarily passes off into the upper atmosphere as soon as it is formed. But over time and under special conditions the tiny amounts of helium produced by radioactivity can become trapped and accumulate in natural gas reservoirs deep in the earth. This apparently is the source of helium as a mineral resource, and four natural gas fields lying in the panhandle country of Texas, Oklahoma, and Kansas contain the bulk of our helium reserve. Together these fields contain about 150 billion cubic feet of helium, a sizable quantity even when compared with the 2 billion cubic feet of annual consumption expected by 1990.

But the fortunate geologic accident that gave us low-cost helium deposits at the same time created a conservation problem that brings the possibility of exhaustion uncomfortably close. As the natural gas is drawn from its underground reservoir, helium flows along with it. The two can be separated at the surface but they need not be, for the percent or so of non-combustible helium usually contained does not detract greatly from the value of the gas as fuel. If it is not extracted, the helium merely passes into tile atmosphere when the gas is burned. Thus—and this is the crux of the conservation problem—helium is being consumed just as much by non-use as by use. Since the helium-bearing gas fields are a main source of fuel supply for the midwest, the only feasible way to conserve the major portion of our domestic helium reserve is to extract it from natural gas before burning and to store it until it is needed.

The full extent of the problem of helium conservation has just recently been recognized. It produced the only specific resource-oriented program recommended by the National Academy of Sciences in the 1962 Report of the Committee on Natural Resources to the President of the United States. Concern over mounting consumption has been heightened by an awareness that US helium reserves are apparently fixed, for despite the vast increase in gas well drilling and an exhaustive sampling procedure, no significant helium-bearing natural gas field has been discovered in the United States since 1943.

Government interest in helium originally stemmed from its high military value, with perhaps some admixture of a desire to avoid a private monopoly. Between 1921 and 1945 the US Bureau of Mines built a series of plants to supply helium for military needs and for the relatively small civilian market. The first helium storage program also stemmed from military needs. In order to make sure that large quantities of helium would be readily available in an emergency, the Bureau built helium extraction plants after World War II with a capacity somewhat in excess of the consumption levels then current. The excess was then pumped into a depleted gas reservoir—the only conceivable place to store billions of cubic feet of gas—to be held until needed.

Little change was needed when the goal of the helium program shifted from military reserve to conservation for scientific and industrial uses. Rather than erect new plants, the Bureau of Mines contracted to buy helium from natural gas companies that undertook to erect their own recovery facilities. Helium production from both government-owned and contract plants is now in excess of 2 billion cubic feet per year, a level that should be greater than current consumption until about 1990, after which time the conservation reserve will gradually be depleted.

The rare occurrence of helium, the unusual uses, the dominance of government agencies in both production and consumption, and the fact that seemingly everyone supports conservation—all lead one to forget that helium is an economic good, that like other economic goods it is subject to laws of supply and demand, and that effective government policy must be predicated upon understanding these relationships. A study done at the request of a special federal interagency helium committee by Lee E. Preston, of the School of Business Administration, University of California, Berkeley, and David B. Brooks, RFF research associate, is the first overall economic evaluation of the federal helium program.

One portion of the study deals with the question of how much helium should be placed in storage over the next thirty to forty years. Somewhere between not saving any and the futile attempt to save every trace of helium there must be an optimum. The authors argue that the federal helium program should be expanded until the cost of production and storage (about $12 per thousand cubic feet), accumulated at an appropriate rate of interest until the time of consumption, is greater than the price consumers conceivably would be willing to pay at that time. For example, the sum of $12 expended for the production and storage of one thousand cubic feet of helium in 1965 will result in accumulated costs, at 4 percent compound interest, of $32 by 1990, $85 by 2015, and $228 by 2040.

What uses of helium exist in sufficient volume and value to justify storage until these future years? Even assuming that increases in price would bring substantial decreases in such uses as metallurgy, welding, and certain missile applications, and a substantial measure of secondary recovery, there remain a number of applications in whipped helium would continue to be used, even at much higher prices. Substitute materials for such uses as cryogenic research, lifting gas, and leak detection are either inferior or nonexistent, and it is just these uses that are expanding most rapidly.

Are there, however, alternate sources of helium supply that might place constraints upon the size of the storage program? No one would pay the high cost of stored helium if they could get it more cheaply from a different source. Several alternative though high-cost sources of helium can be identified, the most promising of which involves by-product recovery of helium from plants at which oxygen is being recovered from the atmosphere. Even though in this process only one part of helium is recoverable for every 40,000 parts of oxygen, the growth of oxygen consumption in industry is such that the potential helium supply is becoming sizable. As technology reduces the present exorbitant costs of recovering atmospheric helium, there will come a point in time, say about 2040, at which it will be more efficient to turn to this inexhaustible source.

At one time it seemed as if helium was a classic—and perhaps the only—example of a natural resource whose available supply was absolutely fixed. On closer study it turns out that helium represents only a slightly more extreme case of the normal problems of mineral exploitation. Though it is not possible for a market system to operate given the peculiar conditions of occurrence and consumption of helium, it is possible to bring economic considerations to bear on the questions posed by government production, storage, and distribution of helium.