Wind moves up the agenda as a dry season complement to Indonesia's hydropower

Indonesia has spent much of 2026 talking about solar. The 100 gigawatt peak programme, the toll road corridors, the rooftop portfolios and the floating arrays on reservoirs have all drawn attention, and reasonably so, because that is where the volume sits. On 16 September the conversation widened. Speaking to reporters at the Parliament Complex in Senayan, Jakarta, after a working meeting with Commission XII of the House of Representatives, the Director General of New, Renewable Energy and Energy Conservation at the Ministry of Energy and Mineral Resources, Eniya Listiani Dewi, made a case for wind that rests less on ambition than on timing.

The argument is seasonal. Indonesian hydropower is strongest when the rains are, and weakest in the long dry months. Wind behaves in the opposite way. Between June and October the archipelago sees sustained wind through the full twenty four hour cycle, and prolonged heat tends to strengthen rather than weaken it. Put simply, the resource that fades is matched by a resource that arrives.

Until now, for the last four years, there has been no wind power investment. Yet it would be excellent if we could harvest wind at the times when water levels are low.

That framing turns wind from a standalone renewable into a system service. It is an argument about complementarity rather than competition, and it is one that public institutions planning at the provincial level can act on directly.

What is operating now and what is planned

Indonesia's operating wind fleet remains small and concentrated. Two plants carry it. PLTB Sidrap in South Sulawesi has 75 megawatts across 30 turbines. PLTB Tolo in Jeneponto, also in South Sulawesi, has 72 megawatts across 20 turbines. Together that is 147 megawatts, on a grid whose ten year plan calls for 69.5 gigawatts of new capacity, roughly three quarters of it renewable.

The distance between that fleet and the plan is the story. Katadata reported the Director General as placing wind at 11 gigawatts in the 2025 to 2034 electricity supply plan, spread across South Sulawesi, East Java, South Kalimantan, Maluku and East Nusa Tenggara. It is worth noting that the plan as published in 2025 was widely reported as allocating 7.2 gigawatts to wind. Sirkularium notes the discrepancy rather than resolving it, since the two figures may reflect different vintages of the same pipeline. Either way, they describe the same essential situation, which is a planned build out roughly two orders of magnitude larger than the installed base.

The resource map has also grown. In 2024 the ministry identified approximately 2 gigawatts of wind potential in northern Java measured at 140 metres above ground level, a hub height that modern turbines reach comfortably and that earlier Indonesian assessments did not consider. Measuring at greater heights has repeatedly enlarged wind potential in other markets, and it appears to be doing the same here. The Director General said she had recently visited both operating wind sites in order to understand directly why new investment had not followed them.

Concessional finance looking for a destination

The financing signal is the part that changes the near term picture. The Director General said the ministry had been approached by the Just Energy Transition Partnership with an offer of lending on very soft terms, and that she had directed the offer toward wind or floating solar. Her stated reason was acceleration, including the pace at which verified emission reductions can reach the carbon market.

This matters because the binding constraint on Indonesian wind has rarely been the resource. It has been the cost of capital measured against an electricity tariff. Wind projects are capital intensive at the front and inexpensive to run afterwards, which makes them unusually sensitive to the interest rate attached to the first decade of operation. Concessional money applied at that point moves the levelised cost of electricity more than almost any other intervention available to government.

Directing the same facility toward floating solar is consistent rather than contradictory. Floating arrays sit on reservoirs that already have transmission, water rights and an operator in place, and they reduce evaporation from the same reservoirs whose levels are under pressure. A facility that can serve either technology gives the ministry the option to place capital wherever the interconnection is already built, which is the fastest route from signature to generation.

Southern Sulawesi is the working example

The theory has a live case, and it sits in the same province as both operating wind farms. Available capacity from hydropower in the southern Sulawesi system has fallen from about 850 megawatts to roughly 250 megawatts, a decline of 600 megawatts, affecting PLTA Poso, PLTA Bakaru, PLTA Malea and a number of minihydro plants. PT PLN attributes the decline to hydrological conditions shaped by El Nino.

The response has been quick and layered. The Minister of Energy and Mineral Resources, Bahlil Lahadalia, confirmed on 16 September that substitute generation was being arranged while conditions normalise. PLN's President Director, Darmawan Prasodjo, has been leading the effort in the field, with roughly 627 megawatts of additional capacity being mobilised into the system and a target of returning supply and demand to balance by the end of September 2026.

The longer term answer is the more interesting one for planners. Under the national 100 gigawatt peak solar programme, PLN intends to strengthen the southern Sulawesi system with approximately 5.2 gigawatt peak of solar generation and 8.2 gigawatt hours of battery energy storage.

This combination will make the southern Sulawesi system more diverse, more flexible and more resilient.

Solar adds supply that does not depend on rainfall. Storage holds it across the evening peak. Wind, on the seasonal logic set out in Jakarta on 16 September, would add a third source that is strongest precisely when the reservoirs are lowest. A province that today illustrates hydrological exposure could become the clearest domestic demonstration of how to design that exposure out.

Pricing reform is the piece that unlocks the rest

Alongside the financing offer, the government is revising Presidential Regulation 112 of 2022 on the acceleration of renewable energy development for electricity supply, with the pricing mechanism as a central element. The revision has been driven largely by the requirements of the 100 gigawatt peak solar programme, but a tariff framework that works for solar will also determine whether the wind pipeline attracts sponsors.

Wind needs slightly different treatment from solar in one respect. Its output is less predictable hour to hour but more valuable seasonally, and a pricing framework built around a solar production curve does not automatically capture that value. A ceiling price that recognises dry season delivery, or a contract structure that pairs wind output with hydropower dispatch inside the same balancing area, would price the complementarity the Director General described rather than leave it unrewarded. This is a design question with a clear answer available, and the revision now under way is the moment to settle it.

Sirkularium's view

For government and public institutions, three practical points follow from the week's developments.

First, seasonal complementarity is a planning tool that can be used now, before any new tariff is issued. Provincial energy plans in South Sulawesi, East Nusa Tenggara, Maluku, East Java and South Kalimantan can be assessed for wind and hydropower assets sitting in the same balancing area, and the pairing evaluated on dry season firm capacity rather than on annual energy alone. That analysis draws on data the system operator already holds, which makes it a matter of sequencing rather than new expenditure.

Second, concessional capital moves fastest where preparation is furthest advanced. The Just Energy Transition Partnership offer will land wherever there is a permitted, interconnected and bankable project ready to receive it. Provinces that want a share of that facility are best served by finalising land status, grid connection studies and resource measurement campaigns at 140 metres now, rather than after a pricing regulation is signed.

Third, the value of resilience is worth stating in numbers. Southern Sulawesi has just shown what 600 megawatts of reduced hydropower capability costs a system in mobilisation, fuel and management attention. Quantifying that cost gives a defensible basis for valuing the diversification that wind, solar and storage provide together, and it converts a resilience argument into a budget argument that planning and finance ministries can evaluate on their own terms.

What to watch next is straightforward. The content of the revised Presidential Regulation 112, and whether it differentiates wind pricing. Whether the concessional facility is formally allocated, and to which projects. And whether the southern Sulawesi system returns to balance by the end of September as PLN has targeted, which will be the first public test of how quickly a diversified portfolio can be assembled when the water runs low.