Introduction
The International Solar Alliance (ISA), launched in 2015 by India and France and headquartered in Gurugram, India, was created to mobilize US $1 trillion in solar investments by 2030 and boost solar deployment in “sunshine countries” across the globe pv magazine International+5Wikipedia+5The Hindu+5. Initially comprising over 100 signatories, ISA has steadily transitioned toward over 120 member countries, demonstrating its expanding global footprint and influence in clean energy policy Wikipedia.
The alliance’s growth highlights its evolving role—from an India-led South–South climate diplomacy initiative to a strategic platform driving solar transition in emerging economies.
Membership Expansion: From Tropics to Global Reach
ISA membership was originally focused on countries within or partially within the Tropic of Cancer–Capricorn belt, also known as “sunshine countries” IAS Google+2Wikipedia+2Reddit+2. However, the ISA Assembly's decision in 2023 expanded eligibility to all UN member states, regardless of geographic location, allowing even nations beyond the tropics to join—though with limited voting rights The Hindu+2IAS Google+2Wikipedia+2.
Recent accession highlights include:
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Armenia, which joined in November 2023, raising membership over 106 full members Business Standard+9Wikipedia+9IFP Info - News+9.
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Moldova, which became a member in late 2024 IAS Google.
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Angola, the 123rd member, joined in May 2025 during a state visit to India IAS Google.
Today, ISA counts over 120 UN member countries, including major global economies like the United States, Japan, France, Australia, Brazil, and Argentina Wikipedia+1IFP Info - News+1.
Regional Growth: Africa and South Asia in Focus
Africa
ISA engagement in Africa has accelerated dramatically:
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Of 46 African countries that have signed on, 38 are now active participants, with 20 of them joining just in the past year, per ISA’s regional head for Africa Reddit+3The News Mill+3pv magazine India+3.
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At its 6th Regional Committee Meeting in Abidjan in 2024, ISA launched demonstration solar projects in Djibouti, Ethiopia, The Gambia, Mauritius, and Senegal, showcasing scalable solar applications The Hindu+4pv magazine India+4Business Standard+4.
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Indian industry engagement has ramped up, with ISA calling on Indian private-sector firms to lead solar infrastructure development across Africa—projects ranging from USD 50 million to 400 million per country The News Mill.
South Asia
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Nepal ratified ISA’s Framework Agreement in June 2024, becoming the sixth South Asian country to become a full member isa.int+3isas.nus.edu.sg+3IAS Google+3.
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India remains ISA President through 2026, with France elected Co-President and Ashish Khanna set to become Director‑General in March 2025 isa.int+4Business Standard+4pv magazine International+4.
Key Initiatives Driving Expansion
SolarX Global Accelerator
ISA’s SolarX Global Accelerator 2025, launched in collaboration with Business Mauritius and Bloomberg Philanthropies, aims to support solar startups across ISA member countries. Running from February to December 2025, the program includes workshops, mentorship, investment readiness, and regulatory guidance for scale‑up innovations isa.int.
STAR‑C and Demonstration Projects
The Solar Technology Application Resource‑Centres (STAR‑C) initiative supports emerging markets with technical training. Energy access programs such as Solar for She, Global Solar Facility, and data-sharing platforms coordinate ISA’s technology deployment across member states. These efforts are integral to demonstrating scalable solar solutions across underserved regions pv magazine India+1The News Mill+1.
Green Grids Initiative / One Sun One World One Grid
ISA co‑leads the Green Grids Initiative – One Sun One World One Grid (GGI‑OSOWOG) with India, France, and the UK. The vision is to link regional grids—from South Asia and Southeast Asia to Africa—creating a global renewable energy network with targeted capacity of 2,600 GW by 2050 Wikipedia.
Strategic Implications of Expansion
Power of Collective Solar Diplomacy
ISA’s growing membership amplifies the voice of the Global South, aligning with India’s diplomatic leadership and enhancing its soft power. By creating a shared platform for developing and least-developed countries, ISA drives climate equity and energy justice.
Leveraging Indian Expertise and Private Sector
India’s successful solar transition—from rural electrification to rooftop solar—positions it as a trusted partner for African nations. ISA encourages Indian firms to play a leadership role in deploying solar solutions and offers de-risking support for on-ground projects The News Mill.
Bridging Policy Gaps and Capacity Building
ISA’s expansion is enabling policy support services, capacity-building programs, and financial mechanisms like the Global Solar Facility (GSF). These initiatives help countries frame bankable solar projects and attract investment RedditReddit.
Global Energy Integration
With grid connectivity ambitions through GGI‑OSOWOG, ISA is driving integrated energy markets, improved energy access, and supply diversification across continents. Expansion ensures that these projects are inclusive and multipolar in scope Wikipedia.
Challenges & Growth Path Ahead
Administrative and Governance Complexity
With 120+ countries onboard, coordinating policies, funding flows, and project pipelines is increasingly complex. ISA must maintain governance integrity while scaling impact.
Resource Mobilisation vs. On-ground Impact
Despite ISA’s ambitious $1 trillion investment target by 2030, disparity in policy readiness, financing environments, and technical capacity may limit actual outcomes. Bridging that gap remains critical IAS Google+3isas.nus.edu.sg+3pv magazine International+3.
Geopolitical Sensitivities
ISA membership is open to all UN states—China has been invited, but has not yet joined. India welcomes inclusion to diversify solar value chains and strengthen southern collaboration The Hindu.
Conclusion: A New Era for Solar Cooperation
ISA expansion reflects more than membership growth—it signals rising southern ownership of the climate and energy agenda. With over 120 participating countries, India at the helm, and strategic initiatives across Africa and South Asia, ISA is fast maturing into a global platform capable of driving real solar deployment.
Sustaining this momentum will depend on:
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Operationalising large-scale financing (through Global Solar Facility and public‑private partnerships)
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Scaling demonstration projects and replicating locally adapted solar applications
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Investing in regulatory and technical capacity building across emerging solar markets
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Enabling integrated grid infrastructure with GGI‑OSOWOG to connect regional solar markets
As ISA continues to expand—bringing in countries like Angola and Moldova—it offers a vision of clean energy leadership led by the Global South, with India serving as its diplomatic and strategic anchor. The expansion is not just quantitative; it advances the qualitative ambition of transforming global solar cooperation into a truly inclusive and impactful climate solution.