Indonesia’s Renewable Energy Milestone: Karangkates Floating Solar Power Plant Reaches 70% Completion

MALANG, INDONESIA – In a significant stride toward Indonesia’s ambitious energy transition goals, the Karangkates Floating Solar Power Plant (PLTS Terapung Karangkates) in Malang Regency, East Java, has officially reached a construction milestone of 70 percent. As of late September 2026, the project remains on track to begin commercial operations before the end of the year, signaling a major leap in the nation’s renewable energy capacity.

Developed by PLN Nusantara Power, a sub-holding of the state-owned utility giant PT PLN (Persero), the Karangkates project represents a critical component of the government’s strategic plan to diversify the national energy mix. With an investment value nearing $100 million USD, the facility is poised to become one of the most significant floating solar installations in the region, utilizing the vast surface area of the Karangkates (Sutami) Reservoir to generate clean, sustainable electricity.

Main Facts: A Technical Overview of the Karangkates Project

The Karangkates Floating Solar Power Plant is not merely a local infrastructure project; it is a high-tech energy installation designed to maximize efficiency while minimizing environmental disruption. According to the latest data released by PLN Nusantara Power, the project boasts an installed capacity of 100 Megawatts alternating current (MWac), which translates to approximately 133 Megawatts-peak (MWp) on the DC side.

Once fully operational, the plant is projected to generate enough electricity to power approximately 35,000 standard Indonesian households. This massive output is achieved through thousands of high-efficiency photovoltaic (PV) panels mounted on specialized floating structures (floats) that are anchored to the bed of the reservoir.

Key technical and financial highlights of the project include:

• Location: Sutami/Karangkates Reservoir, Malang Regency, East Java.
• Current Progress: 70% as of September 2026.
• Total Investment: Approximately $100 million USD.
• Capacity: 100 MWac / 133 MWp.
• Environmental Benefit: Reduction of carbon emissions by thousands of tons annually.
• Operational Target: Q4 2026.

By utilizing the water’s surface, the project bypasses one of the primary hurdles of solar energy in densely populated areas like Java: land acquisition. Java’s high land value and agricultural importance make large-scale land-based solar farms difficult to implement. Floating solar technology provides a "win-win" solution by using existing hydropower infrastructure sites for dual-purpose energy generation.

Chronology: From Blueprint to 70% Completion

The journey of the Karangkates Floating Solar Power Plant began several years ago as part of the Indonesian government’s updated Electricity Supply Business Plan (RUPTL), which shifted focus heavily toward "green" energy.

Phase 1: Planning and Feasibility (2023–2024)

Following the success of the Cirata Floating Solar Plant in West Java—the largest in Southeast Asia—PLN identified the Karangkates Reservoir as a prime candidate for a similar installation. Feasibility studies were conducted to assess the water level stability, wind speeds, and the impact on the existing hydropower plant (PLTA Sutami).

Phase 2: Financing and Tendering (2024–2025)

The project secured its $100 million investment through a combination of internal PLN funding and strategic partnerships, potentially involving international climate finance. The procurement of specialized floating components and high-tier solar panels followed, ensuring the materials could withstand the humidity and aquatic environment of the reservoir.

Phase 3: Construction and Assembly (Early 2026–Present)

Construction began in earnest with the assembly of the floating platforms on the shores of the reservoir. These platforms were then towed into position and anchored. Throughout the third quarter of 2026, workers have been focused on the "stringing" of solar panels and the installation of underwater cabling that connects the floating arrays to the onshore substation.

As of September 29, 2026, aerial surveys and ground reports indicate that 70% of the physical infrastructure is in place. The remaining 30% of the work involves final panel placement, inverter synchronization, and rigorous testing of the grid connection to ensure stability when the power begins to flow into the East Java electricity grid.

Supporting Data: The Advantages of Floating Solar Technology

The decision to build on water rather than land is backed by significant scientific and economic data. Floating solar, or "floatovoltaics," offers several unique advantages that are particularly relevant to the Indonesian climate.

1. Enhanced Efficiency through Natural Cooling

Solar panels tend to lose efficiency as they heat up. In a floating configuration, the water beneath the panels acts as a natural heat sink, cooling the PV modules. Studies have shown that floating solar panels can be up to 5% to 10% more efficient than their land-based counterparts due to this cooling effect.

2. Reduction of Water Evaporation

The Karangkates Reservoir is a vital water source for irrigation and hydropower. By covering a significant portion of the water surface with solar panels, the project reduces the amount of direct sunlight hitting the water, thereby decreasing evaporation rates. This helps preserve water levels during the dry season, ensuring the longevity of the reservoir’s primary functions.

3. Synergistic Infrastructure

The Karangkates site is already home to the Sutami Hydropower Plant. By building the solar plant at an existing power generation site, PLN can utilize existing transmission lines and substations. This "hybridization" of hydro and solar energy creates a more stable power output; solar generates power during the day, while hydro can be managed to provide peak power or base load at night.

4. Land Conservation

To build a 100 MW solar farm on land, hundreds of hectares of space would be required. In East Java, such land is usually used for rice paddies or housing. The Karangkates project avoids the socio-economic complexities of land relocation and preserves agricultural land for the local community.

Official Responses: Government and PLN Nusantara Power

The progress at Karangkates has drawn praise from various sectors of the Indonesian government and energy industry. Officials emphasize that this project is a testament to Indonesia’s commitment to the "Just Energy Transition Partnership" (JETP) and the goal of reaching Net Zero Emissions by 2060.

PLN Nusantara Power Management stated in a recent release that the Karangkates project is a "national priority." A spokesperson for the company noted:

"We are working around the clock to ensure that the 70% progress we see today translates into a fully operational plant by the end of the year. This is not just about meeting a deadline; it is about proving that Indonesia is a leader in floating solar technology. The integration of 133 MWp into the grid will significantly reduce our reliance on fossil fuels in East Java."

Local Government of Malang Regency has also expressed support, citing the potential for "Green Tourism." Officials believe that the sight of thousands of shimmering solar panels on the reservoir could become an educational attraction, drawing visitors interested in renewable energy and sustainable development, thereby boosting the local economy.

Ministry of Energy and Mineral Resources (ESDM) representatives have highlighted that Karangkates is a "blueprint" for other reservoirs across the archipelago. With hundreds of man-made dams in Indonesia, the government views floating solar as the fastest route to scaling up renewable capacity without the friction of land disputes.

Implications: Economic, Environmental, and Regional Impact

The successful completion of the Karangkates Floating Solar Power Plant will have far-reaching implications for Indonesia’s energy landscape.

Economic Transformation

The $100 million investment has already created hundreds of local jobs during the construction phase. Once operational, the plant will require specialized maintenance teams, fostering a new generation of "green-collar" workers in the Malang region. Furthermore, by lowering the carbon intensity of the regional grid, East Java becomes a more attractive destination for multinational corporations that have strict "green energy" requirements for their manufacturing facilities.

Environmental Stewardship

The shift from coal-fired power to solar is essential for Indonesia, which remains one of the world’s largest coal producers. The Karangkates plant will offset a massive volume of CO2 emissions. In a region like Malang, known for its natural beauty and agricultural output, reducing the environmental footprint of power generation is vital for preserving the local ecosystem.

Energy Security and Reliability

By diversifying the energy sources in East Java, the grid becomes more resilient. The hybrid nature of the Karangkates/Sutami site means that the region is less vulnerable to fluctuations in fuel prices or supply chain disruptions associated with coal and gas.

A Model for Southeast Asia

As the world watches Indonesia’s energy transition, the Karangkates project serves as a case study for other tropical nations. It demonstrates that with the right investment and technological application, existing water infrastructure can be transformed into modern power hubs.

Conclusion: Toward a Greener Future

The 70 percent completion of the Karangkates Floating Solar Power Plant is more than just a construction milestone; it is a symbol of Indonesia’s evolving energy identity. By the end of 2026, when the first electrons from the Karangkates sun begin to power homes in Malang and beyond, it will mark a definitive victory for sustainable development.

As the panels are laid and the final connections are made, the Karangkates project stands as a beacon of what is possible when technology, government will, and environmental necessity align. For the 35,000 households soon to be powered by the sun, and for the nation striving toward its Net Zero future, the horizon looks remarkably bright.