Contributed by Amanda Morris and Lauren Winstel, Research Assistants, ACS Green Chemistry Institute®

 

Fig1-helium.pngAs the second most abundant element in the universe, it seems strange to think of helium as endangered. The gas has a wide variety of uses, from cryogenics (think super-cooling MRI magnets) to SCUBA diving equipment [1] (See Figure 1). The problem: Unlike most other elements, helium is so light, it escapes the Earth’s atmosphere with ease, and thus the supply is being constantly depleted.

 

On Earth, helium is a result of the naturally occurring radioactive decay of uranium and thorium [2],[3]. Some of that helium is trapped along with natural gas in the Earth’s mantle. Helium, at concentrations as high as seven percent, may be separated from natural gas via fractional distillation during routine processing.  However, these concentrations are often much lower, with current technology only allowing helium extraction to occur in natural gas wells containing 0.3 percent or greater concentrations of helium[4].

 

The United States currently controls the world’s largest helium supply, the National Helium Reserve, in Amarillo, Texas. The Helium Act of 1925 created this reserve to ensure provisions for airships and the U.S. Navy. This strategic supply then became integral to the Space Race and the Cold War in the 1950s and 1960s.

Today, the natural geologic gas storage in Amarillo – the Bush Dome Reservoir – holds 670 million cubic meters of helium. As a frame of reference, that is enough helium to fill the Goodyear blimp almost 8,000 times[5]! The U.S. Geological Survey (USGS) estimates the total helium resources within the United States to be 20.6 billion cubic meters1. Globally, that number increases to 51.9 billion cubic meters.

 

With that much estimated helium in reserve, why should anyone worry?  Let’s take a closer look. One potential way of looking at this abundance is to consider resource availability and production viability over the long term. In 2014, the U.S. extracted 76 million cubic meters of helium from natural gas and withdrew 24 million cubic meters from storage[6] – or in terms of percentages, approximately 0.49 percent of total known U.S. resources in a single year. Of these 100 million cubic meters of helium, 43 million were consumed domestically, and the remaining 67 million cubic meters were exported. In 2015, the U.S. imported 7.4 million cubic meters in addition to its domestic production. Altogether, this usage percentage rate may seem low, but considering that the U.S. is the world’s largest supplier of helium, a deterioration rate of approximately one percent every two years might be a bit alarming. Consider that very little helium is recycled due to the cost of the machines needed to capture the gas. Most helium simply dissipates into the atmosphere after use, so there is no getting back the 0.49 percent that is lost each year. When extending this analysis to global statistics: 165 million cubic meters of helium were extracted or recovered in 2014, depleting global reserves by 0.32 percent.

 

fig2-helium.pngThis is arguably alarming in itself, but perhaps more so if one considers that helium demand is expected to increase. During 2014, helium consumption in the U.S. increased by 7.7 percent and is expected to continue to increase at a rate of about two percent per year3. Due to the lack of data on foreign markets, it is difficult to forecast global helium demands. However, the National Research Council estimates that global demand will increase approximately three percent annually through 2020 (See Figure 2).

 

With helium reserves being depleted annually, questions over future supplies arise, and unfortunately, there are no easy solutions. Helium is a finite resource; once gone, it will take millions of years to replenish. Our current technology does not allow us to artificially produce helium, nor can we extract helium from the atmosphere[7]. There are, however, options to reduce our reliance on helium production.

 

One possible option is to raise the price of helium, which will cause the element to become too expensive to waste. In 2015, the price of helium for government users was $3.06 per cubic meter ($85 per thousand cubic feet). The price increased by 69 cents for non-government users. Helium is inexpensive due in part to the Helium Privatization Act (HPA) of 1996 and the Helium Stewardship Act (HSA) of 2013. The HPA was passed to recoup the original cost of obtaining the reserve ($1.3 billion). This act required helium stores to be sold off at a fixed rate by 2015, regardless of market value. The HSA was passed in 2013 to increase the market price of helium and reduce helium waste. Unfortunately, the price of helium has not risen at the expected rate[8].

 

Nobel Laureate Robert Richardson[9] states the price of helium should be raised by 20- and 50 -fold to make recycling worthwhile[10]. While the helium used in magnetic resonance imaging (MRI) is occasionally recycled, most large volume applications do not recycle helium.

 

The greatest concern in regard to the future inability to extract helium is how heavily mankind relies on the element. Helium’s primary use is cooling the superconducting magnets located in MRIs and nuclear magnetic resonance (NMR) scanners. Additionally, researchers across the physical sciences and engineering disciplines rely heavily on liquid helium to perform experiments and maintain instruments. There is currently no substitute, neither elemental, chemical nor synthetic, for this purpose. This is due to helium’s extremely low boiling point, 4.2 K, just four degrees short of absolute zero. If helium is not available for use in NMR and MRI machines, scientists will have to invent new ways of imaging to support modern medicine.

 

With between 25 to 50 years of helium remaining, it is clear we need to rethink its consumption. As chemists and scientists, we are at a critical point and uniquely poised to alleviate this problem based on how we use and reuse helium, and all the chemical processes we synthesize related to this element. It is our duty and responsibility to ask how we can improve – for ourselves and for our children – because if we do not, who will?

 


[1] https://minerals.usgs.gov/minerals/pubs/commodity/helium/mcs-2016-heliu.pdf

[2] Nature 179, 213 (26 January 1957); doi:10.1038/179213a0

[3] http://journals.aps.org/pr/abstract/10.1103/PhysRev.74.1590

[4] https://www.aps.org/policy/reports/popa-reports/upload/HeliumReport.pdf

[5] http://www.goodyearblimp.com/behind-the-scenes/current-blimps.html

[6] https://minerals.usgs.gov/minerals/pubs/commodity/helium/myb1-2014-heliu.pdf

[7] https://phys.org/news/2010-08-world-helium-nobel-prize-winner.html

[8] http://www.sciencemag.org/news/2015/07/new-us-rules-helium-sales-said-stifle-com petition

[9] https://www.nobelprize.org/nobel_prizes/physics/laureates/1996/press.html

[10] http://www.zmescience.com/science/chemistry/wasting-helium-recycle-052543/

 

 

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