Türkiye’s geothermal fields are no longer being judged solely by how much electricity they generate. A new review published in Discover Energy argues that the country’s real opportunity lies in squeezing more value from each produced fluid: recovering carbon dioxide for liquid CO2 and dry ice, using CO2 to tame stubborn scaling, extending district heating networks into summer cooling, and screening saline brines for lithium and other critical raw materials. The review, authored by Serhat Tonkul, Taygun Uzelli and Alper Baba, brings together geology, geochemistry and field operations in a single integrated framework.

The geological foundation explains why Türkiye is so well endowed. The country sits in one of the most seismically active sections of the Alpine-Himalayan belt, where the westward escape of the Anatolian block, active fault systems, graben structures and young magmatism combine to produce elevated heat flow. GPS-based studies place the westward movement of Anatolia relative to Eurasia at roughly 20 millimetres per year in Central Anatolia and about 30 millimetres per year in the southwest. In Western Anatolia, north-south extension, normal faulting and crustal thinning have created the Büyük Menderes, Gediz, Simav and Küçük Menderes graben systems, which host the country’s highest-enthalpy fields, including Kızıldere, Germencik, Pamukören and Alaşehir.

The numbers behind this resource are substantial. Türkiye has identified 415 geothermal fields with temperatures of 30 degrees Celsius and above, of which roughly 84 percent are low- and medium-temperature areas suited to direct use, while about 16 percent are high-temperature fields capable of power generation. Installed geothermal electricity capacity grew from just 23 megawatts electric in 2006 to 1,663 megawatts electric in 2022, when 65 plant units were operating. By the end of 2025, the Ministry of Energy and Natural Resources reported 68 geothermal power plants with approximately 1,786 megawatts of installed capacity, generating about 11.6 terawatt-hours, or 3.2 percent of Türkiye’s total electricity production of 362.9 terawatt-hours that year.

Direct use, however, carries much of the resource’s economic weight. As of 2022, Türkiye’s installed thermal capacity for direct use stood at 5,113 megawatts thermal, distributed across thermal tourism at 47.8 percent, central heating at 27.8 percent and greenhouse heating at 24.1 percent. Greenhouse heating covers 5,293 decares of agricultural land, and more than 520 spa facilities serve an estimated 20 to 23 million visitors annually. Cascaded systems in places such as Germencik and Denizli-Sarayköy already route fluid sequentially from power generation through heating to lower-temperature uses before reinjection.

The review’s first flagship example is the Kızıldere field in western Türkiye, where carbon dioxide-rich non-condensable gas separated during power generation is not simply vented. Part of the gas stream is sent to a dedicated production unit, where it is cleaned, compressed, liquefied and, when needed, converted to dry ice, the solid form of CO2 used for cold-chain transport, food preservation and industrial cleaning. Citing work by Karabacak and colleagues, the review reports that producing CO2 from the plant’s raw condenser gas cost 167 US dollars per ton, compared with predicted costs of 190 to 200 US dollars per ton for conventional alternative production methods. The authors are careful to note that because dry ice sublimes after use and the CO2 returns to the atmosphere, this is a utilization option rather than permanent carbon storage.

The second case study addresses one of geothermal operations’ most persistent headaches: scaling. At the Tuzla geothermal field in northwestern Türkiye, the produced fluid is a hypersaline sodium chloride brine with a strong tendency to form dense, chemically resistant metal-silicate deposits in wells and surface equipment. Earlier work showed that formic acid dosing could reduce silicate scaling but raised corrosion and chemical-handling concerns. In a field pilot test, Topcu and colleagues mixed CO2 directly into the hypersaline brine. Dissolved CO2 forms carbonic acid, lowering pH gradually without introducing a strong acid, which helps keep silica in solution and delays polymerization. In the Tuzla tests, CO2 dosing was at least as effective as formic acid at reducing deposit formation while causing less corrosion on metal components, though the authors stress the approach remains site-specific and dependent on brine chemistry, pressure and equipment design.

Cooling is the third value pathway, demonstrated at Balçova-Narlıdere near İzmir. The district heating system there has operated since 1996 and now carries a thermal capacity of around 160 megawatts thermal, serving tens of thousands of residence equivalents from reservoirs reaching approximately 140 degrees Celsius. In 2018, the operator installed Türkiye’s first geothermal-driven absorption cooling unit, which uses lithium bromide technology. Geothermal water enters the system at about 90 degrees Celsius and leaves at about 85 degrees Celsius, while chilled water is delivered to the building circuit at roughly 6 to 9 degrees Celsius, cooling nearly 1,900 square metres of indoor space. Because heat, not electricity, drives the absorption cycle, summer cooling demand can absorb geothermal heat that would otherwise sit underused outside the winter heating season, easing seasonal pressure on the electricity grid.

The fourth pathway looks beneath the chemistry of production to what is dissolved in the brine itself. At Seferihisar, southwest of İzmir, thermal waters are saline sodium-potassium-chloride fluids, a type generally more capable of transporting dissolved metals than dilute bicarbonate waters. The highest reported lithium concentration in the field is 13.4 milligrams per litre, recorded in the Cumalı area near the Tuzla Fault Zone, alongside a boron concentration of 17.5 milligrams per litre and an electrical conductivity of 33,600 microsiemens per centimetre in the CM-3 drilling sample at 153 degrees Celsius. Estimated lithium reserves for the reservoir range from 583 tons, according to Aydın and colleagues, up to larger figures of 1,269 and 2,325 tons. The review cautions that these values are an initial indication only, not proof of economic recoverability, and that repeated sampling, flow-based mass calculations and pilot-scale extraction tests are the necessary next steps.

Tuzla itself shows what pilot-stage extraction looks like in practice. Lithium concentrations in the field range from 20 to 40 milligrams per litre, and researchers have tested sorbent materials including relatively inexpensive electrolytic manganese dioxide compared with lambda-manganese dioxide in a mini-pilot reactor, determining optimal operating parameters of pH 12, an adsorbent concentration of 3 grams per litre and an initial lithium concentration of 200 milligrams per litre, with a maximum lithium uptake of 6.4 milligrams per gram. Field tests have also identified delta-manganese dioxide as a promising sorbent for rubidium, caesium and francium ion extraction. The review places these efforts firmly at the screening and laboratory or pilot stage, distinguishing them clearly from commercially mature operations.

The overall message is a reframing of what counts as geothermal success. The authors benchmark each application against its closest conventional practice and note that evidence maturity varies widely: CO2 recovery at Kızıldere is linked to commercial operation, absorption cooling at Balçova-Narlıdere is a field demonstration, CO2-based pH control at Tuzla is field-tested but site-specific, and critical raw material recovery remains at pilot-stage screening. Future projections cited in the review anticipate installed geothermal power capacity reaching 3,000 megawatts electric by 2030 and 6,000 by 2050, with direct-use capacity potentially reaching 73,956 megawatts thermal by mid-century. Whether those targets are met sustainably, the review concludes, will depend less on new drilling than on reservoir pressure maintenance, effective reinjection, scaling and corrosion control, and the integrated management of heat, gases and dissolved materials already flowing through Türkiye’s wells.

Subject of Research: Integrated uses of geothermal resources in Türkiye, including CO2 recovery, scaling control, district cooling and critical raw material screening

Article Title: Integrated geothermal applications in Türkiye for energy carbon management and resource recovery

Article References: Tonkul, S., Uzelli, T., & Baba, A. (2026). Integrated geothermal applications in Türkiye for energy carbon management and resource recovery. Discover Energy, 6(1), Article 94. https://doi.org/10.1007/s43937-026-00214-8

Image Credits: AI Generated

DOI: 10.1007/s43937-026-00214-8

Keywords: geothermal energy, Türkiye, Kızıldere, Tuzla, carbon dioxide recovery, dry ice, absorption cooling, district heating, lithium, critical raw materials, scaling, Western Anatolia