The Crazy Plan to Send Solar Power From Australia to Singapore, Explained.

In July 2020, the Australia–ASEAN Power Link (AAPL) was given major project status by the Australian government – a recognition only bestowed upon ventures that bear the greatest economic and strategic significance to the country. The AAPL aims to send energy from the sweltering depths of the Australian outback to Singapore through a 3,750km undersea power cable. If it succeeds, the plan would include the world’s largest solar plant, the world’s largest battery, and the world’s longest submarine power cable.

In Singapore, however, the reception has been more restrained. While authorities from the city-state have been in talks with Sun Cable, the company behind the project, they have yet to give it its official support.

What explains the difference in these reactions? We find out in today’s explained.

The Project

Donning an estimated price tag of AU$22 billion (S$21.87 billion) the AAPL is unprecedented. It entails the generation of renewable energy by a 14-gigawatt solar farm with a 33 gigawatt-hour (GWh) battery storage unit in Australian Northern Territory. All in all, the site would take up more than 12,000 hectares, or about 16% of Singapore’s total land mass, and generate gigawatts of electricity that equates to the total output of 9 million rooftop solar panels.

The electricity generated at the solar plant will then be sent overhead for 750km to Darwin, the Northern Territory’s capital. It further gets transmitted to Singapore using a 3,750km undersea high voltage direct current (HVDC) cable.


Despite having received initial financial backing by some of Australia’s richest people, the project still has to traverse quite the distance before reaching the horizon. Particularly, it faces three large obstacles that stand in its way.

Technical viability

Submarine power cable being laid. (Source)

While there are other undersea power cables around the world, none come close to the magnitude of the project. The next longest cable, the Norway-to-Britain North Sea Link, is six time shorter in length, and has not been deployed yet. David Griffin, Sun Cable’s Chief Executive Officer, acknowledges this, saying that artificial intelligence would help in the technical design of the project.

“No one has combined those technologies into a single project of this nature before. It is beyond a human’s ability to design it,” he said.

Part of the problem has to do with the varying depths of the seas the cable transverses. In one potential route, the first 400km and the last 1600km of the cable would lie in shallow waters around 100 to 200 meters deep. The middle section, which passes through the Timor Trough, is extremely deep, going down up to 1900m with many steep slopes.

Both of these sections pose unique problems. Shallow waters, especially in the busy Singapore Straits, exposes the cable to damage from anchoring ships. The cable would also have to avoid existing pipelines and communications cables – both of which exist in abundance along the route between Singapore and Indonesia. In addition, the high amount of electricity passing through the cable might cause deviations in the navigational equipment of vessels passing above.

Laying cables in the deep section of the route also leads to a paradox of sorts. While Sun Cable has previously confirmed that the width of the cable would be somewhere between five and 12 inches, the precise width of the cable really matters. A cable that is too thick could be so heavy that it buckles under its own weight while being lowered. Conversely, a cable that is too thin might not be able to withstand the pressures of the sea.

With that being said, a study published on the Energy Transitions journal concluded that an undersea connection between Singapore and Australia “although relatively ambitious, is technically feasible”. The differing depths could, for example, be combatted by using different cable designs along the route.

Shocks to Singapore’s energy market

Singapore’s power plants are mostly powered by natural gas. (Source)

Singapore’s response to the project is also emblematic of another problem – a potential disruption to the island-state’s energy market.

In Singapore’s wholesale energy market, power generation companies bid to sell electricity every half-hour. Depending on electricity demand and supply, the price of electricity in the market changes every hour. In theory, energy producers would place bids that correspond with their short-run marginal costs.

Electricity retailers then buy this electricity in bulk from the wholesale electricity market and compete to sell it  to consumers.

The complicating factor here is that is that solar power providers like Sun Cable are likely to have substantially lower short-run marginal costs as compared to traditional generators and hence would bid at lower prices. In an attempt to counteract this, traditional generators could withhold supply in order to increase the spot prices in the market.

Since Sun Cable can only provide about 20% of Singapore’s overall demand, a decrease in supply could lead to increased prices for consumers and potentially even energy inadequacy.

The Pan-ASEAN grid

Sun Cable hopes to utilise Singapore as a regional hub that connects to other Southeast Asian countries, via a pan-ASEAN  grid, in the hopes of affording them benefits such as energy security.

Interconnections between Southeast Asian countries have already been established; as of November 2016, nine-cross border links have been created. The successful realisation of a pan-ASEAN grid, however, faces encumbering factors. From technical challenges such as licensing requirements and a country’s state of technology, to financial ones like the expropriation of assets. In addition to those, the strong sense of  political distrust among Southeast Asian countries is a very real reality that further slows down the successful realisation of the pan-ASEAN grid.

Singapore’s incentives

However, the Singaporean government does have incentives to support the project.

On the first level, Singapore has had an obsession with energy security. This is why the country has readily adopted Liquified Natural Gas (LNG) over the years. Instead of merely receiving piped gas from Malaysia and Indonesia, LNG can be transported on tankers from around the world. This denies the island’s neighbours from potentially having a strategic advantage if relationships sour. Having solar power from Australia would improve Singapore’s energy security position through diversification.

The AAPL might also help Singapore transition to more sustainable sources of energy, considering that domestic prospects for solar, wind and geothermal energy are low.  Furthermore, about 95% of Singapore’s electricity production can be attributed to the use of natural gas at the moment. Diversification of the types of sources prevents external shocks from affecting Singaporeans.

These incentives might convince authorities to allow Sun Cable limited access to Singapore’s energy markets. Dr Tan See Leng, Singapore’s Second Minister for Trade and Industry, has said in parliament that while they welcome the project, there is a need “to pace these imports to ensure that they do not undermine the reliability of our electricity supply and the stability of our electricity market”.

This pacing of imports could be done using a vested contract, where companies are allowed to import a pre-determined amount of electricity at a specific price, thereby avoiding market volatility. Considering that the two stakeholders are already in discussions, this might already be in the works. There is a hope then that one day, Singaporean homes might indeed be powered by the rays of sun attacking the Australian outback.


Peter Kosasih


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