Geothermal energy: Deeper rock sample studies in Sembawang show promising results, say scientists

Key Concepts:

• Geothermal Energy Potential
• Temperature Gradient
• Enhanced Geothermal Systems (EGS)
• Advanced Geothermal Systems (AGS)
• Subsurface Temperatures
• Heat Extraction Technologies
• Geological Context
• District Heating
• Southeast Asia Geothermal Landscape

1. Promising Geothermal Energy Potential in Singapore:

• A second study in Sambawang has revealed more promising geothermal energy potential than an earlier study in Admiral T.
• Scientists drilled approximately 1.8 kilometers underground in Sambawang and found temperature gradients higher than global averages.
• A roughly 2-meter deep well produced heat energy at subsurface temperatures reaching up to 120°C.
• This is significantly higher than the 70°C recorded at 1 kilometer in the Admiral T well.
• Professor Romanoli stated that the temperature near the Sambawang site (SMA1) increases unusually fast, with a large temperature gradient.
• Extrapolating the temperature gradient to 5 kilometers suggests a potential temperature of 200-250°C, suitable for electricity generation and cooling data centers.

2. Depth and Temperature Relationship:

• The deeper you go, the hotter it gets, increasing the potential for energy extraction.
• The challenge lies in tapping into this deep geothermal heat safely and cost-effectively.

3. Sambawang Study Details:

• Dr. Po mentioned that the drilling site is located 600-700 meters away from Sambawang Hot Springs, along Gambas Avenue.
• The site was chosen for its size, road access, and availability for 8-9 months of continuous drilling.
• Dr. Po's role involved studying the rocks, sampling, laboratory measurements, and assisting with presentations and manuscripts.
• The drilling took about 9 months, but temperature data collection required long waiting periods for stabilization, with at least 10 measurements taken for finalization.

4. Widespread Underground Heat:

• There is a belief that underground heat is widespread across Singapore, but more data points are needed.
• The northern part of Singapore is considered promising, and additional data points would improve the temperature profile.
• Bulattokong is another potential location due to its hot spring, where a colleague measured a temperature of about 90°C.

5. Heat Extraction Challenges and Technologies:

• Professor Romanoli explained that the heat is not due to volcanic activity, so extraction requires drilling deeper and injecting fluids to exchange heat with the hot rock.
• Two main types of extraction technologies:
  • Enhanced Geothermal Systems (EGS): Involves fracturing rocks to create permeability.
  • Advanced Geothermal Systems (AGS): Involves drilling channels underground and flowing water or working fluid to bring heat upwards.
• Both EGS and AGS have pros and cons and are developing rapidly. Their viability depends on the geological context and region.

6. International Response and Collaboration:

• Dr. Po stated that the findings have received a positive response from international experts.
• One comment received at a conference was, "Wow, you have 120°C. We only managed to get 90°C at 3 kilometers."
• The temperature threshold for utilization in Singapore and Southeast Asia is higher due to the climate, requiring deeper drilling for electricity.
• NTU is collaborating with regional partners like Indonesia.
• The experience from the project has been valuable in assessing geothermal development in Southeast Asia.
• Areas like Malaysia with underutilized hot springs could benefit from Singapore's expertise and insights.

7. Key Arguments and Perspectives:

• The study provides evidence of significant geothermal potential in Singapore, particularly in the northern region.
• The depth of drilling is directly related to the temperature and potential for energy extraction.
• Advanced technologies like EGS and AGS are crucial for harnessing geothermal energy from hot rocks.
• Collaboration with regional partners can help advance geothermal development in Southeast Asia.

8. Notable Quotes:

• Professor Romanoli: "In fact, we found out that the temperature nearby SMA one increases unusually fast uh almost with a very large temperature gradient... this is good enough to provide and generate a good electricity and potentially to supply cooling to data centers as well."
• Dr. Po: "Wow, you have 120°C. We only managed to get 90°C at 3 kilometers."

9. Synthesis/Conclusion:

The research presented indicates promising geothermal energy potential in Singapore, particularly in the Sambawang region. The high subsurface temperatures discovered offer opportunities for electricity generation and cooling. While challenges remain in safely and cost-effectively extracting this heat, advancements in technologies like EGS and AGS, coupled with regional collaborations, pave the way for future geothermal energy development in Singapore and Southeast Asia. The findings highlight the importance of further exploration and data collection to fully understand and utilize this renewable energy resource.