Study Outlines Potential of Floating Solar in Tropical Regions

Researchers from Australian National University recently analyzed the significant potential of floating solar photovoltaic (PV) systems in areas around the Equator, where wind speeds and wave activity are generally calm. 

 

A 145-megawatt floating solar plant is under construction on the Cirata Reservoir in West Java, Indonesia. Image used courtesy of Masdar 

 

The study found that the most favorable sites are centered around the Indonesian archipelago and the Gulf of Guinea near Nigeria in West Africa. In Indonesia alone, offshore solar projects could generate 35,000 terawatt-hours (TWh) annually, nearing the global sum of electricity generation in 2022 at more than 29,000 TWh. In Nigeria, the research team estimated that by 2050, 6 TW of floating PV across 11,583 square miles of territorial seas could cover the population’s energy needs. 

Both countries have high population densities and are experiencing significant growth, making offshore power plants attractive with limited space on land and rooftops. The study mentions that Nigeria – among Africa’s highest-density populations at 250 people per square kilometer – is expected to reach 377 million by 2050, up from 230 million today. Meanwhile, projections from the Indonesian government show the country will top 324 million people in 2045, compared to 279.5 million in 2023. 

Zooming out: The study also estimated that floating solar systems could generate a whopping 1 million TWh annually in regions that rarely see waves larger than 19 feet or winds stronger than 15 meters per second. 

These findings bring great potential as the growth of emerging and developing economies equates to a rise in electricity demand worldwide. The International Energy Agency estimates global electricity demand will speed up by 3% annually from 2023 to 2025, which translates to about 2,500 TWh. For scale, that’s more than double Japan’s annual electricity consumption. By 2025, more than two-thirds of demand growth is expected to come from China, Southeast Asia, and India. 

 

Floating Offshore Solar PV On the Rise

According to a 2022 report from Intersolar Europe, local projects studying the potential of floating PV are underway in over a third of nations worldwide. Cumulatively, estimates count 400 operational plants across over 40 countries, totaling more than 3 GW. Over the next four years, this capacity will grow annually by over 20%, with two-thirds concentrated in Asian markets such as India, China, Indonesia, Taiwan, and South Korea. 

 

Large-scale floating solar system schematic. Image from ResearchGate (Creative Commons Attribution 4.0) 

 

One of those projects is a 145-megawatt (MW) floating solar plant on Indonesia’s Cirata Reservoir. The project was announced in 2020 as Indonesia’s first floating PV plant, delivering power to more than 50,000 homes. It’s expected to be completed this year, according to United Arab Emirates-based Masdar, which is developing the project. 

China’s 320-MW facility on a reservoir in Dezhou is the world’s largest floating PV plant. The developer, Huaneng Power International, completed the two-phase project in December 2023, linking the solar panels to a 100-MW onshore wind facility and an 8-MW energy storage system at the site. 

 

This 320-megawatt project in China is the world’s largest floating PV power station by capacity. Image used courtesy of Huaneng Power International

 

The study notes that Asian countries, including China, Indonesia, India, Thailand, Vietnam, and South Korea, will likely lead future expansion.

 

Wind and Wave Data Informs Floating PV Sites

The study looked at 40 years of maximum wind speed and wave height from 1980 to 2020 to identify suitable maritime areas for offshore floating PV installations. Most of the global seascape hosts waves over 32 feet and winds stronger than 20 meters per second, conditions fueling the ongoing rise in offshore wind projects. However, these sites aren’t conducive to floating solar systems, which require calm wind and wave activity. 

Using this data, the researchers developed a wind-wave map visualization to characterize the most promising sites. They found high potential within Indonesia’s territory, an expansion that would support the country’s latest target to source one-third of its power generation from renewables by 2030.

 

Combined wind and wave data for Southeast Asia (left) and Africa (right): Red areas indicate calm areas with high floating solar PV potential; orange, yellow, and green show lower potential, while blue areas are the stormiest. Gray lines indicate the history of tropical storms. Image used courtesy of the study authors

 

More broadly, Southeast Asia has the world’s strongest potential for maritime floating PV systems across Indonesia, Malaysia, Brunei, Singapore, and Papua New Guinea. The study authors write that an affluent society – meaning high per-capita energy consumption – using all solar PV energy could require 20 MWh per person annually, or 1,000 TWh per 50 million people. Ideal wave heights of around 13 feet and wind speeds of 5-10 meters per second would provide enough energy for 2 billion. This is beyond enough supply for the current population in those five countries, totaling 0.33 billion. 

Southeast Asia's seascape includes 308,881 square miles that haven't seen waves larger than 13 feet or winds stronger than 15 meters per second in 40 years. The area can generate about 210,000 TWh of electricity annually. Considering the current trajectory of population growth, this would be enough to meet the energy needs of 10 billion affluent people in 2050.