Traditional geothermal energy systems rely on extracting heat from shallow underground reservoirs of hot water, where temperatures typically reach above 150^oC, for power generation. However, in Singapore, temperature at locations such as the Sembawang hot spring, only range from 60^oC to 80^oC. This suggests that deploying such traditional geothermal systems is not feasible here.

As technologies develop, deep geothermal systems like the Advanced Geothermal System (AGS) and Enhanced Geothermal System (EGS) tap on heat from hot dry rocks found at depths beyond 3km, and at temperatures greater than 150^oC. “The deeper we go, the higher the temperature. So it’s akin to having a more powerful and efficient engine for electricity generation,” Clarence elaborated.

“In the past, such deep geothermal systems were not economically viable due to their high costs. But over time, the drilling technology has been improving and this helps to reduce the cost of constructing such deep geothermal systems,” Bobby added.

Just last year, an exploratory study conducted by the Nanyang Technological University (NTU) found a site near Admiralty Lane to potentially have deep underground temperatures which are high enough for power generation.

“An area that we are studying is the power plant technology to be coupled with geothermal energy. If high temperatures can be extracted at depth, we could potentially use conventional steam turbines to generate electricity. But if the temperature is not as high, then we may have to consider a different power plant technology with a lower level of efficiency,” Clarence said.

Notwithstanding the exciting possibilities of geothermal, Bobby and Clarence see the importance of staying vigilant as the technology evolves. This is why they closely monitor the development of deep geothermal technologies and pilot studies, particularly in countries like Germany, to understand their operations and challenges. Likewise, the team is on the lookout to attend overseas conferences focusing on deep geothermal technologies.

They pointed out that Singapore, with its limited land space and highly built-up environment, will face distinctive challenges, such as potential impacts on nearby residential areas. Moreover, the economic viability of the technology requires careful evaluation before it can be deemed feasible. Thus, a thoughtful and strategic approach is essential.

“Prior to any potential deployment in Singapore, thorough environmental and safety studies will be conducted to ensure that the technology is safe to deploy,” Clarence said.

To lay the groundwork, a Request for Proposal (RFP) to conduct an island-wide non-invasive geophysical study to assess Singapore’s deep geothermal resource potential at depths up to 10km was carried out. This comprehensive study will provide additional data points and identify suitable locations for potential geothermal power plant deployment.

“At the same time, we’re sparing no effort in engaging local and international academia and industry experts in this field, fostering the exchange of best practices, technological know-how, and understanding the regulations involved,” Clarence shared.

Summing up their perspectives, Bobby and Clarence expressed, “It’s too early to determine if geothermal energy will be a game-changer in our energy landscape. But we are cautiously optimistic that we can tap into a localised, clean energy source right beneath our feet. Achieving this goal will help us decarbonise power generation and reduce our reliance on imported energy.”

[1] Source: National Geographic