Humans have harnessed the heat within the Earth for millennia, perhaps most notably in the ancient Roman baths that served as centers of city life. Far more recently, we have begun to draw upon this geothermal energy—from the Greek roots geo (‘Earth’) and thermos (‘heat’)—as a renewable source of power. The planet contains an astronomical amount of energy: 100 billion times more than the world’s yearly energy consumption. Unlike other forms of renewable energy, moreover, geothermal power is constant: it neither dies down on a still day like wind nor stops at sunset like solar.
The first geothermal planet opened in 1904 in Larderello, Italy, and it still runs today. More than a century later, however, geothermal power only comprises a paltry 0.66% of all global energy production. Even though scientists estimate that almost 40 nations have enough accessible underground hot water to supply 100% of their energy needs, only 7% of geothermal’s vast energy potential has been tapped.
If geothermal power increased from 0.66% to just 5% by 2050, it could reduce CO2 emissions by 16.6 gigatons and save $1 trillion in energy costs. That’s why the Drawdown Organization lists geothermal energy as #18 on its list of the top 100 ways to reverse climate change.
Let’s take a closer look at the potential and challenges of this underutilized energy source.
Geothermal: the Current Situation
You might be surprised to learn that the United States actually leads the world in geothermal electricity capacity; in 2017, its geothermal plants produced about 16 billion kilowatt-hours (kWh). That number becomes less impressive, however, when you realize it represents just 0.4% of the nation’s yearly energy production.
While the U.S. may currently lead the world in geothermal power capacity and production, many developing nations are catching up quickly. Kenya is a particularly impressive success story: since 2010, the percentage of the population with power has ballooned from approximately 20% to 60% due to rapid growth in the geothermal sector. Its Olkaria IV plant, taking advantage of its location above the 2,000 mile-long volcanic East African Rift Valley, has become the largest single-site geothermal facility in the world, and geothermal now accounts for 28% of the nation’s total energy production.
Central America has also become a leader in geothermal energy production. The tiny nation of Costa Rica, for instance, is the 11th-largest producer of geothermal energy in the world. Some of the most impressive initiatives combine electrical power with community empowerment. In El Salvador, women who live near the two geothermal plants that create 27% of the nation’s electricity use waste heat and water to dehydrate fruit and grow plants for personal and commercial use. Almost 50,000 people both directly and indirectly benefit, while the planet reduces yearly CO2 emissions by 1.8 tons.
The Future of Geothermal: Growth and Challenges
Considering how small a share of global energy production geothermal power currently occupies, the only way to go is up. Latin America, for instance, has only tapped into about 5% of the whopping 300 million megawatt-hours per year available; the Andean volcanic belt, in fact, is the world’s largest undeveloped geothermal area.
The future ultimately lies in combining mature hydrothermal and geothermal heat pump (GHP) technologies with a developing technology called EGS, or Enhanced Geothermal Systems. Conventional systems are installed mostly along tectonic plate boundaries where the trifecta of natural heat, fluid, and permeability (the ability for the hot water to rise to the surface) are located.
EGS, in contrast, seek to tap into geothermal energy when only heat is present. EGS is essentially a cleaner version of fracking, since water is injected water into rock in order to fracture it. While the water can be recycled in the process, unlike traditional fossil fuel fracking, the process can still potentially create microquakes, deplete soil nutrients, and disturb wildlife. In the case of Kenya, for example, even its conventional geothermal plants have dislocated the traditional cattle-herding Maasai people and ruined habitats for critically-endangered species.
Moreover, geothermal systems (especially EGS) do emit greenhouse gases—though at far lower rates (anywhere from one-fifth to one-ninth) than those emitted by fossil fuels. Still, it’s always important to remember that no renewable energy source is without its drawbacks, even when it’s utterly worth pursuing.
What You Can Do
When it comes to geothermal energy, as with many of the solutions outlined by the Drawdown Organization, lack of awareness is an important obstacle to overcome. Thus, simply learning about and sharing information on geothermal energy can have an impact, especially if you live in states that can easily access geothermal through conventional systems. Feel free to share this post on your favorite social media sites!
If feasible, you might also consider a geothermal system in your own backyard—literally! Geothermal heat pumps are relatively inexpensive ways to tap into the Earth’s underground heat both to heat and to cool your home or office year-round. While installation costs can be substantial, you’ll save money on your energy bills in the long-run. Moreover, some installations packages offer good rebates through federal tax credits (at least until the end of 2019!) that can offset costs.
Geothermal energy is one of our most untapped sources of renewable energy, both figuratively and literally. When combined with other renewable energy sources, geothermal energy is a key part of the solution to mitigate climate change.