A nationwide study will be conducted to assess how Singapore can harness geothermal energy for power generation, as well as identify suitable locations for building geothermal power plants, said the Energy Market Authority (EMA) on Monday (4 Sep 2023).

Geothermal energy is renewable – it comes from heat derived from the earth’s superheated core, which is estimated to be 2,900 km below the surface.

Previous studies have already indicated geothermal potential in northern and eastern Singapore.

A study by the Nanyang Technological University (NTU) found in July that a site close to the Sembawang hot spring could potentially have temperatures of up to 200 degrees C – the temperature needed for power generation – at depths of 4 km to 5 km, highlighting its potential as a clean energy source.

EMA is asking for proposals for an islandwide, non-invasive geophysical study that will assess Singapore’s geothermal potential at depths of up to 10 km.

The proposed regions to be surveyed in this study would potentially include mainland Singapore (including Sembawang and parts of eastern Singapore), territorial waters, and offshore islands.

Interested parties, which could include both industry players and research institutes, are invited to provide their submissions for the request for proposal by December 8, 4pm.

“As a small, resource-constrained country, Singapore has limited renewable energy options and imports almost all its energy needs,” EMA said.

The country is exploring localised energy options – aside from solar – that would help it diversify and decarbonise its energy resources, in order to hit net zero emissions by 2050.

Therefore, a holistic study is required to determine the overall geothermal potential and scalability of geothermal power across Singapore, added EMA.

Previous studies showed that Singapore has geothermal potential in Sembawang and Pulau Tekong, with the latter having been gazetted for military use.

The study will also help EMA assess the potential for geological carbon sequestration in Singapore – the process of injecting carbon dioxide deep underground for long-term storage to mitigate climate change.

Conventional geothermal systems harness hot water and steam to generate electricity, which is not possible in Singapore due to the lack of viable resources at shallow depths.

However, it is possible to harness geothermal heat from deep underground due to recent advances in technology, EMA has previously said.

For instance, land-scarce Singapore could benefit from closed-loop heat extraction systems, which would require a far smaller surface area per unit of power produced than other types of power plants, including those running on fossil fuel, Professor Alessandro Romagnoli from NTU’s School of Mechanical and Aerospace Engineering told The Straits Times (ST) in July.

In these systems, pipes installed underground in a loop can transport fluids that transfer heat from the hot granite layers to the surface, where the heat could be used to generate electricity in the power plant.

Prof Romagnoli told ST that this is an attractive idea, but drilling at 10 km depth could pose substantial challenges on top of the difficulty involved in extracting heat from the rock.

ST has asked EMA whether a more in-depth study will be conducted at the site near Sembawang hot spring to determine its geothermal potential at 10 km.

NTU is also researching the geothermal potential in Singapore’s eastern region.

For instance, an NTU project involves using a quantum gravity sensor to understand the composition and structure of selected geological sites in Singapore.

Quantum gravity sensors have been used in projects globally to monitor volcanoes, tectonic plates, and the exploration of natural resources.

Co-led by NTU Associate Professor Rainer Helmut Dumke, who is also a scientist at the National University of Singapore’s Centre for Quantum Technologies, and Assistant Professor Wei Shengji from NTU’s Earth Observatory of Singapore, the project can help explore potential sites for geothermal power generation.

EMA had in April 2022 launched a request for information to investigate possible approaches and methods for assessing further geothermal potential in the country. This was done in preparation for the launch of a request for proposal to assess the viability and scalability of deploying geothermal systems in Singapore.

Prof Romagnoli said that a nationwide study could be useful in identifying sites for deep drilling and designing drilling wells, as well as managing project risks.

Aside from northern and eastern Singapore, the western part of the island could also have geothermal potential, he added.

“The eastern side of Singapore features a thin sedimentary layer over a potentially hot granite basement, while the western side of Singapore is characterised by thick sedimentary layers that can act as a heat trap from deeper sources,” Prof Romagnoli said.

“Our near-surface temperature distribution map indicates elevated temperature zones in the western part of Singapore. However, confirming the existence of this thermal resource will require similar exploration efforts,” he added.

Asked about what should be considered when building a geothermal power plant, Prof Romagnoli said that, ideally, the plant should be close to a geothermal energy source. It should also be near the needed infrastructure to distribute the generated power for consumers’ electricity, heating or cooling needs.
 

Source: The Straits Times ©️ SPH Media Limited. Permission required for reproduction.