Southeast Asia’s next phase of growth will depend not only on how fast its economies expand, but also on how effectively they connect. From electricity networks and transport corridors to digital highways and modern health facilities, the region faces an infrastructure investment requirement of $7.1 trillion by 2040, according to a new report released by the Asian Development Bank (ADB) on 10 November 2026. The scale of the challenge is enormous, but so is the opportunity to build a more connected, competitive and resilient ASEAN.
Electricity and Transport Lead the Investment Wave
The largest share of the investment will go towards electricity and transport, which together account for 85% of Southeast Asia’s projected infrastructure requirements. Electricity infrastructure is expected to need approximately $3.6 trillion, while transport will require another $2.5 trillion. These figures cover much more than new construction: they include power generation, transmission and storage, as well as roads, railways, airports and other transport connections.
For a region that has become a major centre of manufacturing and international trade, reliable infrastructure is essential to keeping businesses competitive. Thailand and Viet Nam, for example, have developed important automotive and electronics manufacturing industries, while Indonesia is seeking to strengthen its position in electric vehicle and battery supply chains. Efficient ports, dependable electricity and better connections between industrial centres and markets can help these industries grow and attract further investment.
Roads remain the largest individual transport requirement, with nearly $2 trillion needed through 2040. Railways and airports are also among the areas experiencing rapidly growing investment needs. Better connections between cities, ports and economic corridors could reduce logistics costs, improve access to employment and make cross-border trade more efficient.
Connecting National Energy Systems Through the ASEAN Power Grid
Energy cooperation is particularly important as Southeast Asian countries face rising electricity demand and seek to expand renewable energy. The ADB’s $3.6 trillion estimate covers the wider electricity sector, including generation, transmission and storage. Within this broader requirement, the ASEAN Power Grid offers an opportunity to connect national electricity systems, facilitate cross-border power trading and make better use of renewable energy resources.
The potential benefits can be seen in projects already taking shape across the region. In Cambodia, ADB approved a $52.72 million loan in 2025 to expand the national transmission network, including 55 kilometres of high-voltage transmission lines and upgrades to nine substations. The project is designed to help integrate more renewable electricity into the grid as the country works towards its goal of generating 70% of its electricity from renewable sources by 2030.
Indonesia offers another example through its geothermal development. With geothermal potential estimated at approximately 29 gigawatts, the country has significant opportunities to expand reliable, lower-carbon electricity. ADB has supported state-owned PT Geo Dipa Energi in developing two geothermal power plants, each with a capacity of 55 megawatts, to supply the Java–Bali electricity grid. Additional financing of $180 million in 2025 is helping complete the projects, which are expected to avoid more than 550,000 tonnes of carbon dioxide emissions annually.
In Timor-Leste, ADB provided transaction advisory services for the country's first utility-scale renewable energy facility, combining a 72-megawatt solar plant with a 36-megawatt-hour battery storage system. The project is expected to benefit around 80,000 households, meet approximately 30% of national electricity demand and reduce dependence on imported diesel. Together, these examples show how national projects can contribute to wider regional ambitions for energy security and sustainability.
ADB is also increasing its regional commitment. In May 2026, it announced plans to mobilise $30 billion by 2030 to support ASEAN priorities, including a $5 billion allocation to accelerate the ASEAN Power Grid as part of its wider support for the initiative. ASEAN Secretary-General Kao Kim Hourn welcomed the commitment, describing it as “a powerful signal of confidence in ASEAN’s vision and its capacity to deliver.”
Building Digital Highways and Stronger Public Services
Beyond electricity and transport, Southeast Asia’s digital transformation will require an estimated $584 billion in infrastructure investment through 2040. This includes broadband networks, submarine cables, internet exchange points and data centres. As digital services, e-commerce and cross-border transactions become increasingly important to regional economies, reliable connectivity will be essential for businesses, public institutions and communities.
ADB’s Asia-Pacific Digital Highway initiative, launched in May 2026, is intended to help address these needs by supporting investment in fibre-optic networks, submarine cables, internet exchange points and regional data centres through 2035. These connections could help narrow digital divides between major cities and less-connected communities, while supporting the implementation of the ASEAN Digital Economy Framework Agreement.
Public services are another important part of the investment picture. ADB estimates that healthcare infrastructure will require approximately $227 billion by 2040, including the construction of around 49,000 new facilities, most of them primary healthcare centres. Water and sanitation infrastructure will require a further $244 billion. These investments are essential to ensuring that economic development translates into better everyday services, particularly for communities outside major urban centres.
Turning the Financing Gap into an Investment Opportunity
The scale of the challenge becomes clearer when the financing figures are considered. At current investment levels, government budgets are expected to cover only around 45% of Southeast Asia’s infrastructure requirements, leaving an estimated annual shortfall of $264 billion. Closing this gap will require more than public spending. Governments will need to attract private investors, strengthen public-private partnerships and improve the preparation of projects so that they are financially viable and ready for implementation.
ADB President Masato Kanda captured the region’s priorities when he said, “Southeast Asia’s growth depends on what it builds next.” He also emphasised the importance of dependable electricity for factories and faster, safer access to markets for businesses. The bank has committed $9 billion to Southeast Asia in 2025, comprising $7.3 billion in public sector finance and $1.6 billion for private sector operations, alongside $6.6 billion in cofinancing.
For ASEAN’s 11 member states, the challenge is therefore not simply to raise more capital, but to coordinate priorities and turn regional plans into projects that deliver tangible benefits. Better-connected electricity systems, modern transport networks and stronger digital infrastructure can help countries attract investment while improving access to essential services.
The $7.1 trillion projection is a formidable undertaking, but it also presents an opportunity to shape Southeast Asia’s development for the next generation. With effective partnerships, sound planning and sustained regional cooperation, the infrastructure built between now and 2040 can become a foundation for shared prosperity across ASEAN.
