The result is a high concentration of potential emission-free geothermal energy, one that can form the basis of a carbon-free electricity grid, unlike wind and solar power, which do not typically generate electricity around the clock. The UFO-like Velika Ciglena geothermal plant is the first of its kind in Croatia, and supporters believe the technology will eventually power most of the country’s needs, as well as neighboring countries with similar geology, such as Austria, Hungary and Serbia.
“There is a great potential to generate a lot of electricity from it. There is great potential for district heating. And there is great potential for agriculture,” said Marijan Krpan, the chief executive of the Croatian Hydrocarbon Agency, the state agency that oversees drilling in the country. Krpan said he hopes geothermal energy will eventually generate a third of the country’s electricity needs.
Supporters of geothermal energy are gaining momentum around the world, as technology advances and societies seek every means to reduce the emission of harmful greenhouse gases into the atmosphere. Among other attributes, proponents say, geothermal energy has a relatively small footprint, producing more electricity per square foot than wind or solar power, both of which require more land to generate power. in any quantity. And geothermal power doesn’t have the same waste or safety hazards as nuclear energy, a rival zero-emission source of electricity.
So developers are developing geothermal projects around the world, wherever the soil is good. In Paris, geothermal wells heat elegant 19th-century apartment blocks. In the rugged mountains of eastern California, a large new geothermal power plant opened last August. In Iceland, a small island nation that sits atop countless hot springs, geothermal plants are being used to power the world’s largest carbon capture effort, a new attempt to pull of carbon from the air and pumping it into the ground.
And in Croatia, there are blossoming projects after the government changed regulations in 2016 to allow thousands of disused oil and gas wells to be repurposed for geothermal projects. The northern part of the country is part of the geothermally rich pannonian basin, a region where the continental plates collided about 16 million years ago, then folded back on themselves again and again, creating the fractured rock that allows heat to rise from the earth’s molten core near the surface.
“It’s a treasure,” said Zeljka Sladovic, the founder of GeoDa Consulting and a long-time consultant on geothermal projects in Croatia. For decades, the geologist has worked for the oil and gas industry in Croatia, as the country has long been rich in both resources.
Now the oil is largely depleted, and the country imports most of its gas. But detailed underground maps left over from decades of fossil fuel exploration can help geothermal investors find promising prospects.
In Croatia, that means projects that generate heat for entire districts in cities with centralized heating infrastructure instead of furnaces or boilers in each building. Farmers use technology to heat their greenhouses. And the first geothermal power plant opened last year in the middle of a cornfield outside Ciglena, a village of about 300 people about 20 miles from the Hungarian border.
The Velika Ciglena power plant is an unlikely futuristic addition to a pastoral landscape. 19th-century churches back to fields and forests, and roads wind from Croatia’s elegant capital Zagreb, an hour away. The installation is dominated by 44 large silver fans, each about 20 feet wide, and rotating parallel to the ground, which cools the water before it is pumped back into the ground.
“We have shown the world and the sector that geothermal potential in Croatia is profitable,” said Dragan Jurilj, one of the investors who helped build the power plant and now operates it amid an ownership dispute with his former partners. together with Turkey.
The plant will generate about 17 megawatts of electricity, although due to the way Croatia’s grid operates, it is currently limited to 10 megawatts. At the higher end of the installation, that’s equivalent to the electricity generated by about 94 football fields of solar panels, on an area of land less than a tenth of that.
Skeptics of the efforts say that solar and wind can generate power more cheaply, especially in Croatia, where geothermal water is not as hot as in more volcanic places like Iceland.
“I’m not sure it makes sense from an economic point of view,” said Neven Duic, the president of the International Center for Sustainable Development of Energy, Water and Environment System, a research group based in Zagreb, who said that he thinks that more modest geothermal projects, such as municipal heating plants, are less profitable but may have more social meaning than electricity.
but As the climate warms, supporters of geothermal energy say it can be a good hedge against extreme weather that can sometimes threaten above-ground renewable energy sources. Europe had its hottest summer on record this year, drying up rivers and draining hydroelectric dams of their energy sources, for example.
And now that Russia is causing an energy shortage in Europe by cutting off supplies of natural gas, there is a new impetus to invest in every form of power at home.
“This is our own resource. You don’t need to discuss this with anyone. What could be better than having our own energy in our backyard?” said Dragutin Domitrovic, who served as construction manager when the Velika Ciglena power plant was built and now runs Calida Aqua, a geothermal consulting group.
Geothermal energy usually works by drilling a well a mile or two into the ground and pumping water heated by the energy in the earth’s core. The heat is used to make steam that turns turbines, which generate electricity. The cooled water is then pumped back into the ground. In many places in Croatia’s Pannonian region, water boils a little over a mile down and gets hotter the deeper a well goes.
Hot water leads to more electricity. But there is wide variability from site to site, drilling wells is expensive, and it is often impossible to know in advance whether a drillhole will yield enough water. That should scare investors.
“This is a game that is not for the faint of heart. But with patience you can get there,” said Domitrovic, who said that with energy prices in Europe as high as this summer, he thinks many geothermal projects will break even in seven to 10 years. year.
Croatian authorities are eager to move on. Several new permits for geothermal power plants have been issued in recent months. And the leaders of the government office in charge of the process, the Croatian Hydrocarbon Agency, want to make their focus clearer by changing their name, which dates back to the fossil fuel era.
“We want to change the name of the Geoenergy Agency,” said Krpan, its chief executive.
