Global installed solar capacity has surpassed 3 TW, marking another milestone in the rapid expansion of photovoltaic energy and underscoring the accelerating pace of deployment, according to BloombergNEF (BNEF).

It took about a decade for solar capacity to grow from 100 GW in 2012 to 1 TW, BNEF said. The second TW was added in less than three years, and the third in under two years. BNEF projects global capacity will exceed 9 TW by 2036, with the pace of growth expected to quicken further.

China has been the dominant force behind the second and third TWs, combining rapid domestic deployment with large-scale manufacturing that has driven down technology costs globally. Solar expansion is also reaching previously small markets, with strong growth in Pakistan, Nigeria and the Philippines, and rapid gains in Cuba and Lebanon. The number of countries with at least 1 GW of installed solar rose to 74 in 2025 from 42 in 2020.

Despite broader adoption, deployment remains concentrated. The share of poorer countries in new installations has been largely unchanged since 2020, while China has consolidated its position as the primary growth driver. BNEF expects this to shift from 2026, with developing countries projected to account for more than a quarter of global installed capacity by 2036.

Grid and storage constraints are emerging as the key challenge. In China, solar deployment has outpaced transmission and storage infrastructure, leading to rising curtailment during periods of high output. A slowdown in new Chinese installations is expected as the country pivots toward integration and consumption of renewable generation.

According to BNEF, energy storage is becoming decisive in the next phase of expansion. Without sufficient storage, utilizing additional solar capacity will become increasingly difficult. Transmission, storage and demand flexibility will become as important as new module deployment in converting installed capacity into effectively utilized generation, BNEF said.