The world surpassed 3 TW of installed solar capacity, marking another milestone in the rapid expansion of photovoltaic energy.
According to BloombergNEF (BNEF), it took about 10 years for global solar capacity to rise from 100 GW in 2012 to 1 TW. The second terawatt was added in less than three years, while the third came less than two years later. The exact date of the 3 TW milestone varies, however, depending on the methodology and database used by analysts.
The pace of expansion is expected to accelerate further. BNEF projects that global solar capacity will exceed 9 TW by 2036, putting the latest milestone into perspective against the growth expected over the next decade.
China remains the leading force
The geography of solar expansion has shifted significantly during this period. According to Bloomberg, developed countries accounted for most of the first terawatt, supported by incentive programs designed to accelerate solar adoption.
China emerged as the main driver of growth during the second and third terawatts. The country combined rapid deployment of solar capacity with large-scale manufacturing, helping to reduce technology costs and support adoption in other markets.
Solar expansion is also reaching countries that previously accounted for only a small share of the global market. Pakistan, Nigeria, and the Philippines have recorded strong growth, particularly in rooftop solar. Smaller markets, including Cuba and Lebanon, have also experienced rapid expansion.
As a result, the number of countries with significant solar markets has increased. According to BNEF, 74 countries had at least 1 GW of installed solar capacity in 2025, up from 42 in 2020.
Expansion remains concentrated
Despite broader adoption, solar deployment remains concentrated in a relatively small number of markets. The share of poorer countries in new solar installations has remained virtually unchanged since 2020, while China has consolidated its position as the primary driver of global growth.
BNEF expects this trend to change in the coming years. Its projections indicate that the share of developing countries in new installations will begin to increase from 2026. By 2036, more than a quarter of global installed solar capacity is expected to be located in developing countries, while the share held by wealthy countries is projected to fall to around 20%.
Grid and storage take center stage
The rapid growth in installed capacity is creating new challenges for power systems. In China, solar deployment has outpaced the expansion of infrastructure needed to transmit and store electricity.
As a result, the country is experiencing rising levels of curtailment, with some solar generation being reduced during periods of high output. A slowdown in new Chinese installations is expected as the country shifts its focus toward integrating renewable generation and expanding the capacity needed to consume it.
Energy storage is becoming increasingly important in this transition. Lithium-ion batteries can absorb excess electricity during periods of peak solar generation and discharge it later, including after sunset.
According to BNEF, energy storage capacity will be a decisive factor in the next phase of solar expansion. Without sufficient storage, fully utilizing additional solar capacity will become increasingly difficult.
The 3 TW milestone shows that solar has moved beyond niche technology status and become a central component of global power-capacity expansion. The challenge in the next phase, however, will be different.
As photovoltaic generation continues to grow, transmission, storage, and demand flexibility will become increasingly important alongside the deployment of new modules. The ability to use solar electricity at the right time and in the right place will be crucial to turning growth in installed capacity into effectively utilized generation.
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