Sunday, November 25, 2012

The Story of a Noble Gas

Last week 's blog post explored the golden age of airships, and how nowadays they're used to explore outer space. As I mentioned last week, one of the few airship operators in the U.S. is going out of business because helium prices increased tenfold(!) in the past few years.

The Long Endurance Multi-Intelligence Vehicle: a U.S. military hybrid airship.
Source: Wikipedia.

Helium is the second most abundant element in the universe- why is it getting more expensive? The answer to that question can be traced back to the heyday of airships, the 1920s and 1930s. Back then, it looked likely that the wars of the future would be fought by dirigibles. So in 1925 the U.S. government began maintaining a massive stockpile of the helium gas necessary to float these airships. Ever since then, the U.S. government has been siphoning off helium from natural gas extracted beneath Texas, Kansas, and Oklahoma. The helium is stored in the National Helium Reserve just north of Amarillo, Texas.

The Federal Helium Reserve.
Source: Wall Street Journal

Since helium was essentially a war material, the U.S. banned exports of the gas to the Nazi government in the late 1930s. This meant that the Germans used hydrogen to float the Hindenburg Airship; a risky move, since hydrogen is highly flammable, while helium is inert. Infamously, the Hindenburg caught fire and exploded in the spring of 1937. And its destruction was just one in a series of hydrogen airship accidents throughout that decade.

May 6, 1937: the Hindenburg disaster.
Source: Wikipedia.

Within two years of the Hindenburg disaster, Pan Am began transatlantic passenger flights. Thus ended the demand for transatlantic airship passenger service and mail delivery via airships.  The age of airships was over. Demand for helium plummeted.

Sources of helium in the U.S.
Source: National Academies Press.

With fewer airships around to fill with helium, the Reserve became a costly government expenditure, subsidizing artificially low helium prices. By 1996 it was $1.4 billion in debt. So, that year the Helium Privatization Act was signed, requiring the Reserve to sell off all its gas and close by 2014.

The U.S. government's practice of selling helium at cut-rate prices effectively kept any other potential helium producers out of the market. The Reserve was a massive player in the helium market, accounting for a whopping 30% of the world's helium supply. Naturally, its impending closure has destabilized the world helium market. New helium producing plants in Russia, Qatar, Algeria, and Wyoming are coming online, but replacing 30% of the world's helium supply doesn't happen overnight. Hence the price increases.

The rise in helium prices, 1999-2011.
Source: Washington Post.

So that's the short-term challenge. But there's a long-term helium shortage too. The Earth is running out of helium! How can that be, since it's the second most common element in the universe? Well... it's also the second lightest weight element. Helium doesn't like to bond with other elements to make heavier molecules. Helium atoms generally stay by themselves, and are so lightweight that they eventually float away from Earth, into space. You can produce helium in a lab, but there's no cost-effective way to do that on a large scale right now. Pretty much the only helium you find occurring naturally on Earth is produced inside the Earth by natural radioactive decay.

One use for the world's precious helium supply.

A fraction of the helium produced by natural radioactive sources is trapped below the Earth's surface in natural gas deposits. That's why the Federal Helium Reserve is located next to natural gas deposits: we extract helium from natural gas.

With Airship Ventures closing, who needs helium?  NASA has historically been the world's top industrial helium user. Helium was used to pressurize and purge rocket engines. It's used for many other practical purposes, like cooling the magnets used in MRI machines and particle accelerators.

Helium: It's better than spinach.
Source: Time.

Our supply of natural helium will run out when our supply of natural gas runs out. Given that it's not a renewable resource, some scientists have advocated for creating an international body to regulate the supply and pricing of helium. Some folks argue that the price of helium should be set even higher than it has risen, to eliminate waste (see Popeye, above, for what might be considered a waste).

Helium in action.
Source: NASA.

The short term outlook for helium prices is uncertain. This past spring, a Democratic Senator from New Mexico and a Republican Senator from Wyoming co-sponsored a bill that would stabilize the price of helium by pacing the sell-off of the Reserve's supply. But, as of this week, that bill hasn't moved out of Committee. Assuming it isn't brought to a vote in December, it'll have to be reintroduced when the new legislative session begins in 2013.

A future use for helium: pressurizing and purging the engines of the Ares 1.
Source: NASA.

Sources: NPR; American Institute of Physics; U.S. Department of the Interior; Elko Daily; Time; Wall Street Journal; Washington Post; Wikipedia.

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