The debate over geothermal energy has generally been a quiet one. With just 13 gigawatts (GW) of global installed capacity, it is considered by some to be a relatively non-controversial (or even irrelevant) energy issue. Yet a new study questioning the health risks associated with geothermal power generation could bring this neglected energy source into the spotlight.
Brushing the usual fear-mongering headlines aside, the study raises an important question – what are the risks associated with geothermal power?
The study itself is careful not to equate correlation with causation. The authors suggest that exposure to hydrogen sulfide (H2S) emanating from geothermal power plants near the Icelandic capital, Reykjavik, could have adverse effects on respiratory health. The study further proposes that elevated H2S levels could increase morbidity in people who were already ill. However, the authors conclude that the results “should be interpreted with caution.” Studies on H2S exposure in Rotorua, New Zealand, were similarly inconclusive about the impact of H2S emissions. Further study is clearly warranted.
Iceland is a very particular case. The nation is a global leader in geothermal energy, where it accounts for 66 percent of Iceland’s primary energy use. Geothermal energy is not just used for power generation but also heats 90 percent of the island’s homes. Related: Recession Risk Mounting For Canada
Still, an endless supply of renewable energy has its consequences. Icelanders are the world’s largest per capita electricity users. Industrial electricity demand – in particular from the aluminium industry – has also spiked in the last decade.
As a result, the emissions from geothermal power plants have almost tripled since 2000. The government has responded with stricter regulations designed to reduce the amount of H2S in the atmosphere. Technological innovations in H2S sequestration are already reducing emissions from geothermal power production.
In terms of geothermal energy use, no other nation comes close. Many are far more concerned with emissions from coal-fired plants and other fossil fuels. Still, geothermal power is being increasingly pushed alongside wind and solar as an essential element in any decarbonization strategy.
Geothermal energy is not only the cheapest form of renewable power but also the most reliable. It is the only renewable energy source that can provide baseload power to the grid, complementing the intermittency of solar and wind. Related: A Reality Check For U.S. Natural Gas Ambitions
The greenhouse gas emissions from geothermal are essentially negligible. A U.S. Department of Energy study estimated that the lifecycle greenhouse gas emissions from geothermal power plants were four times less than solar PV and six to 20 times less than natural gas.
Geothermal power plants are also more efficient in terms of land and water use. A geothermal plant requires an estimated 404 mi2 per GWh. This is compared to 3642 mi2 for coal, 1335 mi2 for wind and 3237 mi2 for solar PV.
However, a pessimistic global outlook should not stop nations with geothermal reserves from exploiting their potential. Mexico is one case bucking the trend.
Mexico’s energy reforms, passed in 2014, included new legislation designed to spark geothermal exploration and production. The Federal Electricity Commission (CFE) has just been awarded 13 areas across five states for geothermal exploration. The first private bid round for geothermal is expected to open in August. Related: Buffet’s Solar “Insurance” Coup In Nevada
Mexico’s Energy Ministry (SENER) is banking on the country’s geothermal resource abundance to lower energy costs. SENER estimates that geothermal energy could cost between $55 – 75 per MW, making it the second cheapest renewable energy source and 20 percent cheaper than burning diesel or fuel oil. Mexico estimates its geothermal potential at over 13 GW, or the fourth largest in the world.
The initial results of this strategy will be evident during the first private auction.
Mexico is not the only country in the region hoping for a geothermal power surge.
Nicaragua is promoting geothermal energy as part of a much larger renewable push. Geothermal power now comprises 14 percent of the nation's electricity generation. At an estimated cost of $74 - 92 per MWh (the second cheapest source of renewable energy after wind), geothermal's contribution will continue to rise.
For nations in Central America, in particular, geothermal energy is attractive given the lack of indigenous fossil fuels. The region’s power mix has historically depended on hydropower as well as fuel oil and diesel. Climate change is making hydropower a less reliable resource, while the deleterious effects (and high expense) of burning petroleum are well known.
From El Salvador to Chile to Colombia, Latin American countries are exploring their geothermal options as part of a sustained initiative to diversify their energy matrices. The environmental risks and social backlash against large-scale hydropower further support geothermal’s case.
Overall, the benefits of geothermal power are clear. That said, the lack of controversy surrounding geothermal generation should not be a reason to exempt it from scrutiny regarding its impact on health and safety. As further analysis comes to light, technology and regulatory policy must come together to raise the standard of geothermal power generation. A better understanding of the long-term effects could very well cement the resource’s role in a low carbon energy future.
By Alexis Arthur for Oilprice.com
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