Connecting Indonesia’s First Large-Scale Floating Solar Plant to the Power Grid

The Government of Indonesia is transitioning towards low-carbon energy resources while modernizing its electric power systems, as evidenced by the launch of the highly anticipated 192 Megawatt peak (MWp) Cirata floating solar plant. Located 62 miles southeast of Jakarta on the Citarum River in West Java province, Circatais the largest floating solar plant in Southeast Asia and the third largest in the world. Circata was launched by President Joko Widodo in November 2023, moving Indonesia one step closer to its target of reaching net-zero emissions by 2060 or sooner. However, for variable renewable energy (VRE) like solar to be successfully integrated into the Java-Madura-Bali (Jamali) power grid system (Indonesia’s largest electricity network), state-owned power utility PLN needs to make important adjustments.  

Renewable energy sources such as solar are considered VRE because they are intermittent and dependent on the weather. This variability can create instability on the grid if not managed properly.  PLN has had limited ability to add VRE, resulting in significant changes to the capacity and timing of resource additions and the cancellation of procurements mid-process. 

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Aerial view of the 200-hectare Cirata floating solar plant.

Photo Credit: PLN Nusantara Power

Through the USAID Sustainable Energy for Indonesia’s Advancing Resilience (SINAR) project, USAID supported PLN to integrate higher shares of VRE into the power grid while maintaining grid stability. Modernizing utility planning practices and operations will enable PLN to strategically integrate a higher share of renewable energy.

Experts provided technical assistance and training to PLN to assess and manage the system and operational impacts of connecting large renewable energy projects, such as Cirata, to the grid. SINAR hosted workshops on VRE system operation, dispatching, and planning; modern electricity systems; and control center dispatch functions. In addition, a study tour to Thailand’s 45 MW floating solar system in the Sirindhorn Dam exposed PLN representatives to best practices, methods, and tools. 

To ensure system models reflect actual system operation, SINAR helped PLN update power system data and models on the Jamali grid. Accurate system models are important because they allow engineers and planners to predict how the power grid will behave under different conditions. By running simulations, PLN can identify potential problems before they happen and develop solutions to keep the power grid running smoothly.  

PLN’s power grid was able to successfully integrate 192 MWp of installed capacity from the floating solar plant, powering 50,000 homes and providing electricity access to nearly 326,000 people. The floating solar plant is expected to reduce 3.1 million tons of carbon dioxide equivalent through 2035, which is comparable to preventing the burning of 3.4 billion pounds of coal. 

“This energy transition is very important for Indonesia to maintain the momentum of rapid economic development, accelerate growth, build national capacity, create more jobs, and at the same time, protect the environment,” said PLN President Director Darmawan Prasodjo.