A survey conducted near the Sembawang Hot Springs yielded interesting results. At a depth of 1.1 km below the surface, it was confirmed that there is a high-temperature gradient with temperatures ranging from 60 to 90 degrees Celsius. This is equivalent to the temperature at which an egg can be cooked. The experts' findings show that the country has valuable geothermal energy reserves, which opens up great opportunities for the effective use of this environmentally friendly energy source.
The temperature found is much higher than the temperature of rocks at the same depth in many other non-volcanic regions, such as Europe and Scandinavia. This was revealed by Nanyang Technological University (NTU) Associate Professor Alessandro Romagnoli, one of the leaders of the study.
Comprising a team of scientists from Nanyang Technological University (NTU), the Technical University of Munich's research center at the Singapore Campus for Research Excellence and Technological Enterprise (TUMCREATE), and supported by infrastructure consultant Surbana Jurong, the team found promising potential for geothermal use in an area adjacent to the hot springs in Sembawang, Singapore.
They predicted that temperatures at this site, at depths of 4 to 5 km, could reach an incredible 200 degrees Celsius. This finding brings geothermal energy into the realm of a promising potential source of clean energy, according to Professor Romagnoli, an expert in the field.
In the temperature range between 30 and 60 degrees Celsius, there are opportunities for water desalination and the development of aquaculture. However, once temperatures exceed 90 degrees Celsius, the focus shifts to the ability to cool the region. More interestingly, when temperatures exceed 150 degrees Celsius, this could be an ideal resource for power generation and hydrogen production.
Dr. Tobias Massier, who plays a key role as chief scientist at Tumcreate and is also one of the team leaders in this research, explains that the absorption cooling principle has the potential to convert heat energy into fresh, cool air. In addition, one gigawatt of geothermal power can meet about 12 percent of Singapore's current cooling needs.
Since October 2021, the research team has been actively drilling underground at Admiralty Lane to a depth of about 1.1 km. They have collected rock samples and taken temperature readings at various depths.
This research site, along with the hot springs in Sembawang, is located in a geological region known as the Pluton Granite Junction. The uniqueness of this region lies in the presence of granites that have higher heat production rates, offering exciting potential for geothermal energy exploration.
However, Professor Romagnoli explains that deeper drilling poses more complex technical challenges and is often more costly.
The research team originally planned to drill to a depth of 1.5 km, but ultimately only reached 1.1 km due to unforeseen technical challenges.
Nevertheless, these preliminary results provide the impetus for further exploration to determine the total surface area of the hot rocks in Singapore, the total amount of thermal energy trapped in the rocks, and the rate of heat transfer, Professor Romagnoli said. This information will help determine the optimal location for geothermal power plants, should Singapore decide to proceed with the project.
In October 2021, the Energy Market Authority (EMA) announced its plans to study the potential use of geothermal systems in Singapore, focusing on the northern and eastern regions. These two regions have been identified as having higher surface temperatures and hot springs.
In the context of land-constrained Singapore, the concept of closed-loop heat extraction is an attractive option. This approach allows the use of a much smaller land area per unit of energy produced compared to other types of power plants, including those that rely on fossil fuels," Professor Romagnoli explains.
The underground piping system, forming a closed loop, will carry fluids to transport heat from the hot granite layers to the surface where it can be used to generate electricity at the plant.
To optimize the amount of thermal energy that can be extracted for power generation, the best option is to install a series of pipes that extend into the lateral areas below the surface, as explained below. Ralph Foong, EMA Deputy Chief Executive of Energy Planning and Development, believes that the findings of NTU's study provide an important basis for their efforts to explore the potential of geothermal energy as a renewable energy source of critical value to Singapore.
He believes that geothermal energy has the potential to make a significant contribution to a more sustainable and diverse energy mix if its feasibility can be demonstrated. He expressed his hope to work closely with NTU and other interested parties to conduct a thorough assessment of the full potential of geothermal energy resources in Singapore.
