Advances in Wind Turbine Design Technology: Implications for Indonesia's Wind Energy Sector

Wind energy is a key pillar of the global energy transition, driven by ever-increasing efficiency and cost competitiveness. By 2023, global installed wind capacity will have reached 1.008 GW, with a significant addition of 73 GW in just one year. This underscores the global commitment to decarbonization and the growing maturity of wind technology. As an archipelago, Indonesia has abundant wind energy resources, estimated to total 155 GW, consisting of 60,4 GW of onshore wind and 94,2 GW of offshore wind. Despite this huge potential, the actual utilization is still very minimal, only a fraction of the total potential. Advances in turbine design are therefore crucial to making wind energy economically viable and operationally efficient under these conditions, turning the theoretical potential into a practical energy source.

Technological advances in wind turbine design are key to improving the efficiency, reliability and sustainability of wind energy generation systems, especially in the Indonesian context. These innovations are particularly relevant given the unique wind potential of the archipelago and Indonesia's ambitious targets in the clean energy transition. The use of advanced materials such as carbon fiber and graphene has revolutionized the design of turbine blades. These materials are able to strengthen the blade structure while significantly reducing its weight. This allows turbines to operate more optimally, even in weak wind conditions, which are common in many parts of Indonesia. The global market for carbon fiber wind turbine blades is projected to grow significantly, from US$4,39 billion in 2023 to US$15,9 billion in 2032, with Asia-Pacific as the main contributor, indicating a regional trend towards the adoption of these advanced materials.

Source: Astute Analytica, 2024

The application of optimized aerodynamic profiles, such as the NACA series (e.g., NACA 2410), is essential to match turbine performance to the low-wind characteristics common in Indonesia. These profiles are designed to maximize lift and minimize drag at a given angle of attack, which is essential for efficient energy capture in variable wind conditions. Although NACA 2410 is said to be effective for low wind speeds (supported by a study in Aceh), direct comparison data of the NACA 2410 profile with other profiles such as NACA 4412 or the S series from NREL specifically in the 1,5-6,5 m/s wind speed range prevalent in Indonesia is limited. NACA 4412 is known for its high lift coefficient and low drag, while the S series airfoils from NREL were developed to minimize performance loss in stall-regulated wind turbines. The optimal choice of airfoil is highly dependent on the complex interaction between wind speed range, turbine size and control strategy.

The integration of digital technologies such as the Internet of Things (IoT) and Artificial Intelligence (AI) in turbine monitoring systems is essential to detect faults early and optimize performance in real-time. IoT sensors collect large amounts of data regarding wind speed, temperature, vibration, and power output. This data is then analyzed by AI to predict performance, identify anomalies, and recommend proactive maintenance.

This predictive maintenance capability is crucial for reducing operations and maintenance (O&M) costs, which can be substantial for wind farms. By preventing major failures and optimizing operational parameters, this technology improves system reliability and maximizes energy output. The Sidrap wind farm in South Sulawesi is a clear example of improving wind farm performance through design innovation and modern monitoring systems. Although the specific details of commercial IoT/AI implementation at Sidrap Wind Farm are not extensively described, the research discusses the development of a prototype IoT-based monitoring system for wind power plants, including vertical turbines, to remotely monitor voltage, current, and power. It illustrates the general applicability and benefits of such systems in the Indonesian context, aiming to replace manual monitoring methods with more efficient automated solutions. IoT and AI technologies enable real-time turbine performance monitoring, predictive maintenance, and remote operation optimization. These capabilities enable early detection of potential problems, prevent costly major failures, and enable more efficient scheduling of maintenance activities. By significantly reducing unexpected downtime and optimizing resource allocation for maintenance, IoT/AI directly lowers O&M expenditures, thereby improving the overall Levelized Cost of Energy (LCOE) and increasing project profitability. In addition, remote monitoring capabilities overcome the logistical challenges and high costs associated with accessing and maintaining turbines in remote areas of Indonesia or offshore locations.

The Indonesian government is focusing on long-term targets for the renewable energy mix, with 31% by 2050 and a transition to net-zero emissions by 2060 (with a target of 72% renewable energy by 2060), replacing the outdated 23% target in 2025. In achieving these targets, two wind turbine innovations stand out: Vertical Axis Wind Turbines (VAWTs) and Floating Wind Turbines. VAWTs offer an attractive option for Indonesia due to their ability to operate at low wind speeds and in changing wind direction conditions, a common characteristic in many domestic regions. At Institut Teknologi Kalimantan (ITK), for example, the PUI Fluid-based Renewable Energy team developed a 300W capacity VAWT with a design capable of working in low wind speeds and without the need for wind direction orientation. Additional studies reinforce the potential of VAWTs, such as an intelligent control system with AI-based variable swept area to speed up startup and stabilize power at low speeds, and CFD simulations and experiments of Savonius and H-rotor that show operational efficiency at speeds of 2-6 m/s.

In addition, the concept of floating offshore wind turbines (FOWTs) is emerging as a crucial solution to harness Indonesia's abundant offshore wind potential, especially in deeper waters where fixed-foundation turbines are not feasible. These systems can access stronger and more consistent winds further from shore. ITK also developed a Mobile Floating Structure (MFS) prototype designed to be transportable, allowing it to gain energy in waters with higher wind speeds. Globally, FOWTs such as Hywind and WindFloat have demonstrated the feasibility of floating farms in the deep sea, capturing stronger winds. Although the initial LCOE for FOWTs is higher (€140/MWh in 2018), it is projected to decrease significantly to around $60/MWh by 2040. For floating VAWT in particular, the LCOE can be much more competitive, ranging from around USD 110-213/MWh, due to its compact platform, low center of gravity, and lighter foundation, which drastically reduces CAPEX and O&M. The absence of a heavy nacelle also simplifies maintenance, reducing the need for large, expensive vessels.

In Eastern Indonesia, the development of wind turbines, both VAWT and floating, is faced with significant challenges. Energy infrastructure is still limited, while procurement and logistics costs are very high. Extreme weather conditions such as tropical storms also complicate turbine design and operation. Addressing these challenges requires the development of local human resources who master turbine design, construction and maintenance technologies, as well as local research that takes into account the adaptive regional conditions in the eastern region. Collaboration between universities, local government and industry is essential to develop an implementation roadmap and ensure these innovative solutions can be effectively adapted in the field. In the context of VAWTs, a number of studies have shown that vertical axis designs tend to be cheaper in terms of installation, operation and maintenance than horizontal axis turbines (HAWTs), mainly because they do not require gearboxes, high-mounted generators and complex yaw mechanisms. For example, the X-Rotor design can cut turbine costs by 32% and O&M costs by 55% compared to conventional turbines. As for floating turbines, VAWTs offer a more compact platform, low center of gravity, and lighter foundation that significantly lowers CAPEX and O&M and lowers LCOE to around USD 110-213/MWh, much more competitive than early models. Non-technical innovations such as modularity and ease of installation are also important factors in reducing costs. VAWT components that can be prefabricated and quickly installed on-site cut labor and transportation costs. Likewise, in the case of floating turbines, the lightweight structure and weight release of the nacelle facilitates movement and maintenance without a large ship, resulting in a significant reduction in logistics expenses.

Indonesia faces several significant challenges in developing its renewable energy sector, including regulatory, technical and financial aspects. On the regulatory side, investors complain about non-transparent procurement procedures, the obligation to partner with PLN, as well as complex “deliver-or-pay” schemes and ceiling tariffs that depress the profitability of EBT projects. These conditions are exacerbated by overlapping local mandates and frequent policy changes, limiting long-term business certainty for financiers.

The technical side is also a major obstacle, including limited transmission infrastructure, grid integration, and geographical risks in eastern Indonesia. Financially, the high cost of capital, high interest rates, and lack of access to long-term credit make it difficult to finance RE projects, although instruments such as green bonds and blended finance have begun to be developed. To address this, concrete policy recommendations need to be implemented. The government can simplify and streamline the licensing process through OSS and the one-stop regulation scheme (Perpres 112/2022), accompanied by fiscal incentives such as tax holidays, VAT relief, and import duties on renewable energy devices. In addition, public guarantee schemes such as BVGL and IIGF should be expanded to lower credit risk and attract more private participation. It is also important to have a guaranteed and transparent feed-in tariff to improve the current unfavorable tariff conditions.

Cross-sector collaboration is also crucial. Concrete examples such as PLN Powerchina's partnership in wind potential and feasibility studies across Indonesia demonstrate the synergistic role of SOEs and foreign investors. International support through JETP, which channels funds via ADB up to $500 million, opens up opportunities for EBT infrastructure reform and development. Indonesia can also follow other countries' success story models such as blended finance and green sukuk programs that have proven effective.

The strategy for increasing adoption should cover the following areas:

1. Preparation of detailed renewable energy potential maps by region.

2. Development of energy transmission and storage network infrastructure.

3. Digital establishment and technology localization through human resources through vocational training and collaborative research.

4. Providing fiscal support in priority areas such as Eastern Indonesia. These measures can boost investor confidence, accelerate real projects, and bridge the national energy gap.

The official target of the Ministry of Energy and Mineral Resources and PLN through the draft RUPTL 2025-2035 and RUKN stipulates an additional installed capacity of up to 5 GW of wind power by 2030, confirmed by the statement of Director General of EBTKE Eniya Listiani Dewi on September 27, 2024. This figure is not just a projection, but part of the government's policy in the medium term. The construction of wind power plants in Indonesia involves various global and local players that contribute greatly to accelerating the clean energy transition. Danish giant Vestas has been involved in projects such as Jeneponto Wind Farm (65 MW) and Sidrap Wind Farm (70 MW) in South Sulawesi as EPC contractors, demonstrating the government and industry players' confidence in their technical expertise. Meanwhile, UPC Renewables partnered with PLN through constructive support such as on the Sukabumi Wind Farm project (over 258 MW), confirming their commitment in developing large-scale wind generation in the country.

On the other hand, the role of local companies is no less important: PT Kenertec Power System (KPS), a subsidiary of Korindo Group, manufactures turbine towers. KPS has produced more than 2,500 ISO-certified towers and TKDN of up to 30-40% local materials since 2006, including 30 towers for Sidrap wind farm, and penetrated global markets in America, Europe, and Asia. Although KPS currently focuses on turbine tower manufacturing and not on overall turbine technology design or development (other components such as nacelle, rotor, and control system are still dominated by imported technology), its presence in the supply chain accelerates cost reduction, improves supply chain resilience, and facilitates technology transfer and local labor absorption. All these collaborations are in line with the Indonesian government's commitment to increase the renewable energy mix, reduce fossil fuel dependence, and meet emission reduction targets. The wind farm projects from Vestas and UPC, supported by local component production by PT Kenertec, are clear evidence of the synergy between the government, private sector, and industry in realizing a sustainable energy transition.