For centuries, sea routes have linked the world’s continents, driving global communication and trade. The introduction of submarine cables transformed this connectivity, enabling rapid data transmission across vast oceans and bridging distant islands and continents. The era began in 1858 with the laying of the first transatlantic telegraph cable between Great Britain and the United States, marked by Queen Victoria's message to U.S. President James Buchanan. At that time, transmitting a single word took ten minutes. Today, optical fibres transfer data at incredible speeds, reaching up to 100 gigabits per second.
Now, the world is poised to enter another era where electricity will be transmitted through undersea power cables. Although the concept of subsea power transmission isn't new – the first such cable being the commercial High Voltage DC (HVDC) laid in 1954 between Sweden and Gotland – it has gained traction only in the last decade. (There is another form of cable; the High Voltage AC or HVAC, but this is not preferred due to high level of energy losses during transmission). As the world shifts towards green energy to combat climate change, the need for undersea power cables has become pressing. The reason is renewable energy sources like hydroelectricity, wind farms, and solar power are unevenly distributed, leading to excess generation that often goes to waste. Storing this power in massive battery banks is costly and hence transmitting this excess power to areas of scarcity is the best solution. Advances in high-voltage transmission technology have made it possible to install cables both overland and underwater, connecting regions and continents like never before.
Presently the longest undersea power cable employing the most sophisticated technologies is the Viking Link, spanning 760 kilometres, connecting the United Kingdom and Denmark. With a capacity of 0.8 GW, this groundbreaking cable began operations in December 2023. Its primary purpose is to facilitate the exchange of excess electricity generated from renewable sources, such as solar panels and wind turbines, between the two nations. By enabling this efficient energy sharing, Viking Link ensures that entire surplus green energy is utilized, reducing waste and promoting sustainability.
A global network of submarine cable infrastructure, dedicated to electricity transmission, is rapidly expanding. This emerging landscape has captured the imagination of visionary planners and engineers worldwide, unlocking unprecedented possibilities for intercontinental electricity connectivity.
One revolutionary concept gaining traction is the 24/7 harnessing and global distribution of solar energy. This ambitious idea involves transmitting electricity generated from solar panels during the day to regions experiencing night time, bridging the geographical divide. Imagine solar farms in western India generating electricity at 11:30 am local time on Sunday, instantly transmitting it to the eastern United States, where it's 2:00 am. This continuous, borderless flow of green electricity holds immense potential for humanity.
Although still in its early stages, the idea of a borderless flow of green electricity is already generating excitement among experts, who believe it could significantly curb climate change like never before. The concept involves using undersea cables to create a global electricity grid that ensures a continuous supply of renewable energy. This vision was officially introduced by Indian Prime Minister Narendra Modi in October 2018 at the first assembly of the International Solar Alliance, under the slogan "One Sun, One World, One Grid" (OSOWOG). The initiative gained further momentum in November 2021 during the COP26 meeting in Glasgow, where the UK and India committed to sharing renewable energy resources.
However, connecting countries as distant as the UK and India presents significant challenges. Progress is being made in stages, though. For example, Xlinks, a company focused on green electricity production and distribution, has launched a project to install submarine cables between Morocco and the North Devon coast of the UK. This ambitious undertaking involves laying four cables, each 4,000 kilometres long, as part of a 1.8 GW HVDC subsea cable system. To harness the energy, Xlinks plans to construct a 200-square-kilometer solar farm in the Guelmim Oued Noun region, with the exact location still undisclosed. Additionally, the company intends to establish wind farms in the same area, as winds are strongest during late afternoon and early evening—aligning with peak electricity demand in the UK. These wind farms are expected to enhance the project's financial viability.
This example illustrates how nations can collaborate to produce renewable energy and efficiently distribute it through undersea cables. Similar projects, such as the one between Australia and Singapore, are already in progress. If Singapore connects with India via its east coast, it opens up opportunities for both India and Australia to share their abundant natural resources, like solar energy, with Singapore reaping the benefits. On India's western coast, a connection to the Middle East—rich in solar and wind resources—could be established across the Arabian Sea. Further, there could be a link between West Africa and the United States via the Atlantic Ocean, potentially creating a global grid that supplies uninterrupted renewable electricity from Australia to the US.
However, this vision requires significant financial investment and, more importantly, strong political will. Currently, conflicts in the Middle East and political instability in places like Morocco present challenges. Despite these hurdles, the concept of "One World, One Grid" is very much alive, and undersea power cables are likely to play a key role in its future development.
