A host of solar panels floating in calm seas near the equator could provide nearly unlimited solar power to the densely populated countries of Southeast Asia and West Africa.
Our new study shows that offshore solar systems in Indonesia alone can generate about 35,000 terawatt hours (TWh) of solar electricity per year, which is equal to the current global electricity production (30,000 TWh per year).
And while most of the world's oceans experience storms, some equatorial regions are relatively calm and peaceful. Therefore, relatively inexpensive designed structures can be sufficient to support floating solar panels in the open sea.
Our high-resolution global heat maps show that the Indonesian archipelago near Nigeria and equatorial West Africa have the greatest potential for offshore floating solar panels.
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By mid-century, solar power is regulated
On current trends, the global economy will be decarbonized and largely electrified by 2050, supported by large amounts of solar and wind energy.
About 70 square kilometers of solar panels could provide all the energy needs of a million wealthy people in a zero-carbon economy. The panels can be placed on roofs, in dry areas, near agriculture or float on bodies of water.
However, countries with high population density such as Nigeria and Indonesia have limited areas for collecting solar energy.
Its tropical location in the so-called "cloudy" latitudes also leads to a lack of wind sources. Fortunately, these countries and their neighbors can harvest almost unlimited amounts of energy from solar panels sailing in calm equatorial seas.
Floating solar panels can also be placed on inland lakes and reservoirs. Indoor solar flotation has great potential and is already experiencing rapid growth.
The newly published work examines the world's oceans to find regions that have not seen large waves or strong winds in the past 40 years. Floating solar panels do not require expensive and powerful technical protection in such regions.
Regions with no waves above 6 meters and no winds above 15 meters per second can generate one million TWh per year. That's roughly five times the annual energy needed for a fully decarbonized global economy to feed 10 billion wealthy people.
Most of the good places are near the equator, on and around the equator in Indonesia and West Africa. These are regions with high population growth and high ecological value. Offshore solar panels can help resolve land use conflicts.
Indonesia has great solar energy potential
Indonesia is a country with a high population density, especially on the islands of Java, Bali and Sumatra. By mid-century, Indonesia's population could exceed 315 million people.
Fortunately, Indonesia has great potential for solar energy, as well as a lot of potential for hydroelectric storage to store solar energy overnight.
About 25,000 square kilometers of solar panels will be needed to support prosperous Indonesia once the economy is fully decarbonized and powered by solar energy.
Indonesia has the potential to deploy large numbers of solar panels in its calm inland seas. The region covers about 140,000 square kilometers and has not experienced waves greater than 4 m and wind speeds greater than 10 m per second in the last 40 years.
Indonesia's 6.4 million square kilometers in sea area is 200 times larger than what would be needed if all of Indonesia's future energy needs were met by offshore floating solar panels.
The future of marine solar panels
Much of the world's seascape is exposed to waves over 10m and winds over 20m per second. Several companies are working to develop protection for the panels of sailing ships to withstand storms. In contrast, the benign marine environment along the equator requires much stronger and more expensive protection.
We have found that the most suitable regions are between the 5th and 12th latitudes from the equator, particularly in the Indonesian archipelago and the Gulf of Guinea near Nigeria. These regions have low wind energy potential, high population density, rapid growth (both in population and energy use), and significant intact ecosystems that do not need to be cleared for solar farms. Tropical storms rarely strike equatorial regions.
The offshore floating solar industry is still in its infancy. Offshore solar panels have disadvantages compared to land-based panels, including salt corrosion and marine pollution. Shallow waters are preferred for anchoring panels to the seabed. And great care must be taken to minimize damage to the marine environment and fisheries. Global warming can also change wind and wave patterns. Despite these challenges, we believe that floating marine panels will become an important part of the energy balance of countries with access to calm equatorial seas. By mid-century, about a billion people in these countries will depend primarily on solar energy, bringing about the fastest energy transition in history.
Read more: Sun by day, water by night: Indonesia could combine its massive solar and water storage facilities to decarbonize the country
