In Caldas and Casanare, two geothermal energy projects are in the exploration and exploitation phase. This renewable energy has a very low environmental impact but poses significant financial challenges due to the high investment required.
VILLAMARÍA, Colombia – The heat generated by the Earth’s formation more than 4.5 billion years ago – some of which is still preserved – together with the friction between rocks, minerals, and fluids, has caused temperatures estimated at more than 5,000 °C to emanate from the center of the planet. Few traces of this heat reach the surface, where temperatures usually hover between 30 and 50°C, although in some areas they can exceed 100°C.
On a road trip in Colombia, in Boyacá or Tolima, for example, the signs warn: “Thermal springs two kilometers away”. Depending on the location, these may be natural pools where people bathe or wells where the only thing you can see is the bubbling of boiling water. Another manifestation of this heat on the surface, albeit at much higher temperatures, is the magma found inside volcanoes.
In the 1970s, Colombia took the first steps towards developing a novel way of extracting energy from this heat, but little was known about it. To this end, geophysical and geochemical studies were carried out, which, in simple terms, consisted of x-raying the ground to find out what it was made of beneath the surface.
At that time, geologists were particularly interested in the volcanic complex between Tolima, Caldas, Risaralda, and Quindío, which consisted of several volcanoes such as Cerro Bravo, Cerro Machín, Nevado del Tolima, and Nevado del Ruiz.
In those years, explains geologist Julián López, “the first studies were carried out, which showed that there was a potential for energy production. This led to the preparation of a systematic analysis to identify the points of greatest interest for geothermal exploitation within this large volcanic complex”.
By 1983, Villamaría in Caldas, a municipality very close to Manizales, had been identified as an area of particular interest for a geothermal exploration project. However, the Armero tragedy, which occurred on 13 November 1985 after the eruption of the Nevado del Ruiz volcano, changed the plans.
The researchers, companies, and resources that were to be devoted to geothermal energy were used to create the Manizales Vulcanological and Seismological Observatory, which is now responsible for monitoring the country’s twelve active volcanoes.
The dream of generating energy from the heat of the Earth’s core had to be put on hold for several years. Now it has regained momentum and is close to becoming a reality, but it would still take several years to become operational.
Geothermal energy
In volcanic areas, explains López, who is also vice-president of the Colombian Geothermal Association, high temperatures are more likely to be found near the surface. “It is enough to drill between one and three kilometers to find fluids at 200-300°C.” In Colombia, these areas are abundant because of the high temperatures.
In Colombia, such zones are abundant because its territory lies on the “non-violent ring of fire” that runs from Argentina to Alaska in the Americas and crosses the non-violent coast of Asia and Pacific Oceania.
It is estimated that 75% of the world’s active volcanoes are located there. In geothermal terms, these are known as high-enthalpy zones because they produce temperatures above 200°C, which can be used to generate electricity.
As with almost all forms of electricity generation, the system consists of driving a turbine. To do this, scientists look for water reserves beneath the surface, which, because of the heat, are found as a mixture of vapor and liquid.
“What you’re looking for is a borehole that can access these reservoirs, which flow naturally because of the pressure and temperature they are at. At the surface, the hot water is separated from the steam, which goes to a turbine, drives a generator, and produces electricity,” says López.
In areas with geothermal potential, thermal manifestations like this one are found. The water is found at more than 100°C, so it has liquid and vapor fractions, which causes it to come out under pressure through the hole. Image: CHEC-EPM
After passing through the turbine, the steam condenses and rejoins the rest of the water in a tank to be reinjected into the well from which it was extracted. The energy is sent to transmission lines that can meet the needs of communities near the project or feed into the National Interconnected System to bring electricity to the rest of the country.
Other areas, which are not close to volcanoes but have the geological characteristics to have high temperatures near the surface, are called medium (80-150°C) or low enthalpy (30-70°C).
“These are systems that extract geothermal energy for purposes other than electricity generation. For example, heating for greenhouses or some industrial processes that require temperatures below 70°C,” explains Carlos Vargas, a PhD in seismic engineering from the University of Catalonia and head of the Geophysics Research Group at the National University.
At the Gran Sabana Industrial Park in Tocancipá, for example, a pilot geothermal power plant is in operation, using the temperature of the subsoil to supply a refrigeration plant. Other uses include drying seeds or fruit in agriculture, heating homes, cooking food or the familiar tourist uses.
According to studies carried out in Colombia by the Colombian Geological Service (SGC), geothermal energy could generate around 1,200 megawatts (MW) of electricity, or 5% of the country’s total production.
Globally, Vargas adds, it is already used in more than 20 countries and has an installed capacity of 16 gigawatts (GW), which would meet more than 80% of Colombia’s needs. However, its potential “could be much greater than these modest figures”, says the researcher.
Moreover, it is a resource that has an advantage over other forms of renewable energy generation. Wind and solar power, which are the best known, depend on favorable weather conditions for optimal operation, while geothermal energy “is the ideal resource because it guarantees a stable supply over a long period,” says Vargas.
Yes, the initial investment for such a project is much higher than for other renewable energies.
Where geothermal is going in Colombia
There are two licenses for the exploration and exploitation of geothermal energy in the country. One corresponds to the project that had to be postponed after the Armero tragedy and was resumed five years later. In 1994, with Resolution 0211, the Ministry of the Environment granted the company Geotérmica Andina SA (Gesa) the first environmental license to explore geothermal energy.
In Pirineos, an area in Villamaría, Caldas, where great potential had been identified, a platform was set up for the company to carry out exploratory drilling. The resources came from Central Hidroeléctrica de Caldas (Chec), which owned Gesa, and a Mexican company, so they were prepared to go down to 2,000 metres in search of reserves.But before they started, “the Mexican group failed to agree on the partnership and pulled out. Chec took on the challenge alone and developed the well, but only reached 1,500 meters because the budget was exhausted,” says López, who is currently managing the project.
The well was not productive, even though it registered a temperature of 200°C, because it had no steam flow. With no resources and no success in the first well, “in 1997 it was not very attractive to go ahead with an alternative geothermal project. I think some hydroelectric projects weighed more heavily, the government did not give strong support in this aspect and the project was frozen,” says López.
The project was revived in 2006. With the technological advances that had been made in soil studies, it was decided to update what had already been done. “This allowed us to confirm what had been predicted in the 1980s: the area had a lot of potential. We were also able to get more detailed information on the location of the sites,” explains the geologist.In 2022, after 16 years of work, Chec applied for an update of the environmental license granted in 1994 and defined five points where drilling would be carried out to locate reserves and determine the potential of the wells.
The project has received financial support from the Climate Finance Accelerator (CFA), a UK government-backed program that aims to develop climate change projects with a significant impact on climate change mitigation and adaptation.
The next step, explains López, is to drill these wells and determine whether or not it is feasible to produce electricity. In the plans, Chec estimates that the plant to be installed will generate around 50 MW, energy that would meet the needs of several villages in Villamaría, in addition to being distributed to other parts of the country.
“With an optimistic vision, I would believe that in a few years, if we are lucky, we could go ahead with the project,” says López. Lucky, he clarifies, means that they get all the resources they need and that, once they know the actual generation capacity, it will be enough to make the investment worthwhile.
The other license, granted by the Ministry of Mines and Energy on 27 December, is held by the Canadian company Parex Resources, which is receiving technical advice from the Universidad Nacional Sede Medellín. The project is located in Casanare, in two oil wells, which is the company’s main activity.
Camilo Franco, a professor at the Faculty of Mines of the National University of Colombia (Unal) and part of the team advising the project, explains that it is a low-enthalpy generation that can produce between 15 and 60 kilowatts (KW). This capacity is suitable for domestic use and close to the project where it is produced, as connecting a transmission line would be very costly compared to the amount of energy that could be sold.
Such a geothermal installation, says Farid Cortés, chemical engineer, professor at Unal and also part of this team, is known as cogeneration because it depends on a main activity to be economically viable. “It is a dual production system. Oil is still produced, which is essential,” he adds.
In addition to the financial challenges geothermal projects face, they also require technical precision to ensure that their environmental impact is minimized, as they can have a serious impact on the subsoil.
This is part of the infrastructure used by CHEC to carry out exploratory drilling and geological analysis to determine the potential of the area. Image: CHEC-EPM
Environmental responsibility in geothermal energy
In 2006, the US Department of Energy’s Idaho National Laboratory published a paper entitled The Future of Geothermal Energy.
It states that “when considering the full life cycle of geothermal power plants, their overall environmental impact is significantly lower than that of conventional fossil fuel and nuclear power plants. In addition, their impact can be lower than that of other renewable energy sources such as solar, biomass and wind”.
It is this low environmental impact, together with early developments in Colombia, that has made it so attractive. But that does not mean it is completely harmless to the environment. “In nature, energy is not free,” says Vargas, a researcher at Unal. So, the debate is about how big its impact is compared to the benefits it offers.
On the one hand, Vargas adds, “The interaction of water with hot material can cause fractures and consequently seismicity. There could also be leakage of deep, relatively polluting fluids to the surface. Even excessive water injection could cool the reservoir and make the project unviable.
For Lopez, for example, these are risks that exist, but they could be minimized with scientifically based and rigorously executed protocols. One such protocol to avoid groundwater contamination, the SGC explains, is to install “a steel pipe coated with cement that prevents interaction between the rock and the resource being extracted”.
One of the advantages of this is that it minimizes greenhouse gas emissions. As López explains, in the case of the Ruiz project, the impact is related to the infrastructure that has to be built for the operation, but not to the production of energy itself.
A three-kilometre road to link the wells to a secondary road, drilling platforms, and transmission lines, among other things, are part of the considerations.
Projects such as that of Parex Resources and Unal in Casanare, explains Natalia Cano, a doctor of environmental engineering who is involved in the project, calculate that the production of geothermal energy would reduce the emissions generated by the exploitation of oil in their wells by 54%, something that could reduce the environmental impact generated by this fossil fuel during the period in which the permits for its exploitation are in force.
This article was produced with the support of Climate Tracker Latin America.
VR: EG
