Eden Geothermal Plans Four More Wells in Expansion of Cornwall Renewable Energy Project Eden Geothermal has proposed drilling four additional underground wells at its site near the Eden Project in Cornwall, potentially increasing the total number of wells from two to six. The company says the changes could substantially increase renewable heat and power generation without expanding beyond the development boundary or fundamentally changing the scheme already approved by Cornwall Council. The proposal represents an important test for the future of deep geothermal energy in the United Kingdom. Geothermal power is often associated with volcanic regions such as Iceland, Kenya, Indonesia and New Zealand, but the Eden project relies on the heat stored deep beneath Cornwall’s granite. If the expansion succeeds, it could demonstrate how naturally occurring underground heat can provide dependable low-carbon energy in countries where conventional geothermal resources are less obvious. At the...
Breakthrough in Taiwan’s Deep Geothermal Energy: Academia Sinica and CPC Corporation Drill Nearly 4,000 Meters in Yilan and Find High-Potential Reservoir
Published: December 10, 2025 By: Robert Buluma
In a historic milestone for Taiwan’s renewable energy journey, Academia Sinica (Central Research Academy) and Taiwan’s state-owned CPC Corporation have successfully completed the island’s first-ever “deep geothermal exploratory well” in Yuanshan Township, Yilan County. The well reached a depth of nearly 4,000 meters, recorded a bottom-hole temperature close to 150 °C, and confirmed the existence of an upwelling heat source beneath the northern Yilan Plain. Researchers are now calling it a “high-potential geothermal reservoir” that could become a cornerstone of Taiwan’s green energy transition.
From Anxiety to Excitement: The Temperature Surprise
Dr. Ji-Chen Lee (李建成), principal investigator of the “Taiwan Geothermal Research and Technology Development Project” and researcher at Academia Sinica’s Institute of Earth Sciences, openly admitted that the team grew anxious when the temperature at 3,000 meters was still below 100 °C far lower than what is typically considered economically viable.
“Then something dramatic happened,” Dr. Lee recalled during the press release. “After 3,500 meters, the temperature shot up at an astonishing rate , approximately 90 °C per kilometer. By the time we reached the bottom at nearly 4,000 meters, we measured almost 150 °C. This tells us unequivocally that we are sitting right next to a powerful upwelling heat source , perhaps just ‘one wall away’ from the true high-temperature center.”
In geothermal terms, 150 °C at less than 4 km depth is extremely promising. For comparison, many commercial geothermal fields worldwide operate at 180–250 °C, but modern binary-cycle power plants can generate electricity efficiently even at 100–150 °C. If the predicted hotter zone is only a few hundred meters away horizontally, temperatures could easily exceed 200 °C at just 3 km depth in the core area.
Favorable Geology for Low-Risk Hydraulic Stimulation
Detailed analysis of drill cuttings and logging data revealed that the lower section of the borehole penetrated the Nancun and Zhongling formations ,sedimentary layers with excellent porosity and natural fracturing. These characteristics make the site particularly suitable for the newer, gentler hydraulic stimulation techniques that minimize induced seismicity risks, unlike the controversial methods used in some early Enhanced Geothermal System (EGS) projects overseas.
Instead of massive high-pressure fracturing, the team envisions multi-stage, low-volume water injection to gently connect existing fractures and create an efficient heat-exchange network , a method sometimes called “soft stimulation” or “new-style hydraulic fracturing” in Chinese-language reports. The natural permeability already observed reduces both cost and environmental concerns.
One Well Is Not Enough: The International 3–5 Rule
Dr. Yu-Kao Chen (陳于高), Executive Secretary of Academia Sinica’s Sustainability Science Center, emphasized a crucial lesson from global geothermal development: on average, 3 to 5 exploratory wells are required to properly delineate a reservoir before a power plant can be confidently designed.
“This first well has given us tremendous confidence that the Yilan deep geothermal play is real and worth pursuing aggressively,” Dr. Chen said. “We now need additional wells to construct a precise 3D model of the upwelling plume, map the exact location of the highest-temperature zones, and determine the optimal engineering approach , whether conventional hydrothermal or an EGS configuration.”
The current well has already been converted into a long-term monitoring station equipped with cutting-edge distributed fiber-optic sensing (both temperature and acoustic). The fiber-optic cable, installed along the entire length of the borehole, acts like tens of thousands of sensors, providing real-time data on heat flow dynamics, natural fracture behavior, and subtle ground deformation. This will guide the siting of the next wells with pinpoint accuracy.
Why This Matters for Taiwan
Taiwan’s energy profile is notoriously challenging: over 97% of primary energy is imported, nuclear power is being phased out, and suitable sites for large-scale hydro or onshore wind are limited. The island sits on the Pacific Ring of Fire with enormous geothermal potential, yet decades of exploration focused only on shallow, obvious hot-spring systems in national parks , most of which are either too small or environmentally sensitive for large power plants.
Deep sedimentary basin geothermal, like the Yilan discovery, offers a completely different paradigm: no surface hot springs required, minimal land use (a well pad is only a few hundred square meters), zero air emissions, and a capacity factor above 90% , higher than solar, wind, or even nuclear.
A single 50 MWe geothermal plant , achievable if the reservoir performs as current data suggest , would generate as much electricity as approximately 100–120 large offshore wind turbines, while occupying a fraction of the space and operating 24/7 regardless of weather.
The Road Ahead
The research consortium is already drafting proposals for phase-two drilling in 2026–2027, ideally with expanded government and private funding. The goal is to complete a full 3D seismic survey, drill at least two or three additional deep wells, conduct flow tests, and by 2028–2030 begin construction of Taiwan’s first deep geothermal power station.
Perhaps most importantly, the Yilan success has shattered the long-held perception that Taiwan’s geothermal resources are “limited to scenic areas with hot springs.” It proves that blind, deep, high-enthalpy systems exist beneath the island’s plains , systems that can be developed with low visual impact and in close proximity to existing transmission infrastructure.
As Dr. Lee concluded: “We have just opened a new chapter. Deep geothermal can and should become the backbone of Taiwan’s net-zero pathway. Today’s result is not the end of exploration , it is the beginning of a genuine geothermal renaissance.”
Contact persons for media:
Dr. Yu-Kao Chen ygchen@gate.sinica.edu.tw
Dr. Ji-Chen Lee jclee@earth.sinica.edu.tw
Source: Ocac
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