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| Fig. 1: Yellowstone's Old Faithful geyser. (Source: Wikimedia Commons) |
An eruption of the Yellowstone supervolcano would be catastrophic to the United States. It has been claimed to be more dangerous than an asteroid. It currently releases most of its energy through hot springs and geysers (see Fig. 1), but it stores a fraction that, over time, builds up until it may erupt. NASA has proposed to stop this by drilling 10 km holes above the magma and circulating water to cool down the molten rock, reducing the potential for eruption. The danger of drilling too far could result in depressurization that might lead to the eruption NASA is aiming to prevent. The estimated cost of the project would be $3.46 billion and take thousands of years to potentially cool down the supervolcano. Such an expensive undertaking was proposed to be offset by using the excess heat in the form of steam to drive power turbines leading to a sustainable energy resource (see Fig. 2). [1] Whether or not this proposal could prevent a supervolcano eruption, we will look to Iceland's ongoing geothermal progress to determine the feasibility of this project's energy production.
Iceland has been a leader when it comes to innovative alternative renewable energy sources. It presently draws 49% of its energy from geothermal energy; meanwhile, the United States only uses geothermal energy for 0.5% of its total energy. [2,3] Iceland has even proposed to construct a 600-mile undersea power line to the UK to share its abundant energy. [4]
The motivation for drilling into the supervolcano comes from Iceland's Deep Drilling Project (IDDP), which created the first magma-generated geothermal energy system. The drilling began in 2009 and resulted in a 2.1 km hole flowing 10-12 L/s of 450°C steam yielding up to 35 MW of power. [5] This amount of energy could lead to powering of 28,000 US households (1250 kW per household. [6]) This project, while experimental, demonstrated the ability to extract geothermal energy in a new way.
The original project, known as IDDP-1, has recently been succeeded by IDDP-2. The target depth of this new project was set to be 5 km, which would yield up to an estimated 50 MW with a budget of $15 million. [7]
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| Fig. 2: Schematic of extracting geothermal energy by circulating cold water and capturing the steam. (Source: Wikimedia Commons) |
If we assume that NASA's proposal would be an extension of IDDP-2, NASA's $3.46 billion budget would allow for about 100 10 km deep drill sites. This would lead to an estimated 5 GW of power output from Yellowstone's supervolcano once all sites are drilled and plants set up. [1] This amount of power is comparable to 2 times the amount of power output generated by the Hoover Dam. [8]
In order to recoup on the lofty $3.46 billion investment at the proposed rate of $0.10/kWh, it would require 4 GW of power to be produced for one year. [1] In addition, drilling 100 10 km holes would be a significant time and resource investment.
Whether or not NASA's plan to cool down Yellowstone's supervolcano would work, the project's renewable energy potential has some merit building off of Iceland's geothermal energy innovation. However, the total energy that this project would produce would only account for 3.5% of the United States renewable energy in 2016. In addition, according to BCSE analysis, solar and wind renewable energy have been growing at a rapid rate compared to the almost stagnant geothermal energy contribution. [9] With the danger of also disrupting the supervolcano, the United States should look to continue its investment in the quick growing solar and wind renewable energy over this proposal.
© Jeffrey Granja. The author warrants that the work is the author's own and that Stanford University provided no input other than typesetting and referencing guidelines. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
[1] D. Cox, "NASA's Ambitious Plan to Save Earth From a Supervolcano," BBC Future, 17 Aug 17.
[2] B. Crowe, "Geothermal Energy," Physics 240, Stanford University, Fall 2012.
[3] R. L. Evans, Fueling Our Future: An Introduction to Sustainable Energy (Cambridge University Press, 2007), p. 111.
[4] A. Rosenkranz, "Geothermal Energy in Iceland," Physics 240, Stanford University, Fall 2015.
[5] G. Ó Friðleifsson, W. A. Elders, and A. Albertson, "The Concept of the Iceland Deep Drilling Project," Geothermics 40, 2 (2014).
[6] J. Dondero, The Energy Wise Home: Practical Ideas for Saving Energy, Money, and the Planet (Rowman and Littlefield Publishers, 2017), p. 83.
[7] N. Hurst, "Deep in the Heart of Iceland, There's a New Way to Tap the Earth's Energy," Smithsonian Magazine, 8 Nov 16.
[8] S. Dotson, "Hoover Dam: An Historic Hydro Power Plant," Power Engineering, 08 Dec 15.
[9] Q. Schiermeier, "Solar and Wind Energy Propel Growth in US Renewables ," Nature News, 14 Feb 17.
