Geothermal Energy: An Innovative Approach to Powering America's Future

Editor’s Note: The Millennial Voices series is written by and for Millennials to foster nonpartisan discussion. Jordan Shenhar is a junior at the University of Texas at Austin. The opinions expressed in this commentary are solely those of the author.

Americans from across the political spectrum have long touted sustainable power production as an environmentally conscious pathway towards energy independence. But as alternative energy systems continue to proliferate across the United States, their limitations are becoming increasingly apparent. For instance, solar and wind energy are highly climate-dependent; hydropower can wreak havoc on marine ecosystems; and the prospect of radioactive waste makes nuclear energy a tough sell for politicians and the public alike.

But one largely untapped energy resource has the potential to avoid those kinds of drawbacks. Geothermal systems generate energy through steam turbines, powered by vapors heated in underground rock layers or magma flows. They release few to no emissions and require no resource inputs. And they have enough power to run every electrical grid in the United States.

Costa Rica's Arenal Volcano, close to where a new geothermal plant will begin construction in 2018. (source)

Costa Rica's Arenal Volcano, close to where a new geothermal plant will begin construction in 2018. (source)

So why haven’t they caught on yet? For one thing, we can’t yet access all of that power. No geothermal system is as productive as a nonrenewable power plant. Two of the world’s most recently planned geothermal plants, each of which will begin construction in Costa Rica in 2018, are only expected to produce 55 megawatts of power each—enough, the Costa Rican government hopes, to serve 200,000 homes. In contrast, a typical coal-fired power plant can generate upwards of 500 MW. There are also concerns about the efficiency of geothermal plants. A coal-burning plant can convert about a third of the power it generates into usable energy, whereas a geothermal plant can only do so at about a 12% clip.

Geothermal energy has some problems from an economic standpoint as well. It carries a very high startup cost, because pipes that can withstand extreme conditions far below the surface don’t come cheap. And its inefficiency scares off many investors.

Given these challenges, it makes sense that the U.S. currently gets only 0.2% of its energy from geothermal sources, mostly in Northern California. But a few promising developments could make implementing geothermal energy systems much more viable in the near future.

Lava flow in Iceland, where researchers hope to build the world's most powerful geothermal plant to date.

Lava flow in Iceland, where researchers hope to build the world's most powerful geothermal plant to date.

One such innovation is taking place at a volcanic field in southwestern Iceland, where a team of researchers with the Iceland Deep Drilling Project is trying to tap into hotter and more pressurized water than any system has accessed before. If the project is successful, its geothermal plant would be able to operate at about 70% of a coal-powered plant’s capacity while serving as a laboratory for more efficient methods of storing and transporting underground resources.

But for better or worse, most American communities are not surrounded by active volcanoes or geysers, nor are they built atop underground magma flows or major fault lines. To date, that has prevented geothermal systems from being constructed throughout most of the country. But another emerging technology, called a binary geothermal system, has the potential to put that concern to rest by lowering the temperature needed to power a geothermal plant.

It works like this: Instead of using water to power the turbines, a binary system just uses it to vaporize a different liquid with a lower boiling point (usually butane) before returning the water to the ground for re-extraction. The second liquid’s vapor then powers the turbine, at which point it is cooled and piped through the system again.

Because it never vaporizes the water drawn from the underground reservoir, a binary system carries a few critical advantages over its water-powered counterparts. Since the water returns straight to the reservoir and the plant doesn’t release the other fluid’s vapor, a binary plant releases no emissions. That’s important, because the steam emitted by other types of geothermal plants can carry trace amounts of toxic gases from deep within the Earth.

But what’s most notable about binary geothermal systems is that, because the vapors they use can exist at lower temperatures than steam, they allow for the creation of geothermal plants even in areas without easy access to superheated rock. In the U.S., that means that geothermal energy production won’t be confined to the Far West for much longer.

As more geothermal systems crop up around the world and advancing technologies boost their output, the cost of starting a new plant should fall. If that happens, geothermals would become the most economically viable source of energy available. That’s because an established plant requires few—if any—inputs, making geothermal energy the cheapest source of electricity ever invented. The U.S. Energy Information Administration estimates that geothermal electricity will cost $0.0478 per kilowatt-hour by 2020, or less than half as much as coal, solar, nuclear, or offshore wind energy.

Meanwhile, the range of possible geothermal energy sources continues to expand. The IDDP plans on someday powering its plants directly through magma flows, which would boost efficiency even further. And in the more distant future, geologist Wilfred Elders of the IDDP hopes that some form of geothermal system will be able to harness energy from the Juan de Fuca Ridge off the coast of Washington State, which could produce enough electricity to power all of America.

More so than other forms of alternative energy, geothermal energy appeals to a broad cross-section of American interests, including lower electric costs for the average household, independence from foreign energy sources, and emission-free power that doesn’t severely damage ecosystems. With sufficient political willpower, geothermal systems can play a big role in drawing America’s protracted energy debate to a close.

Jordan Shenhar is a MAP Policy Intern and a junior at the University of Texas at Austin majoring in Government, Economics, and Plan II with minors in Middle East Studies and History. He works as a senior columnist at the Daily Texan, as a research associate in the Lyndon B. Johnson School of Public Affairs, as a peer adviser in the Plan II Honors Program, and will participate in the Next Generation Scholars program at the Strauss Center for International Security and Law starting this fall. 

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