Solar Asset Mapper detects 34.9% year-on-year surge in global installations

London, 2 February 2026: TransitionZero has released the Q4 2025 update of its Solar Asset Mapper (TZ-SAM), bringing total detected global solar capacity to 1,246 gigawatts (GW) after a record year of deployment.

The dataset shows a 5.1% increase in detected capacity compared to Q3 2025 and 34.9% year-on-year growth. TZ-SAM now tracks more than 106,800 solar facilities worldwide, following the addition of 2,085 new sites in the fourth quarter.

Built using planetary-scale machine learning applied to satellite imagery, TZ-SAM is a global, asset-level dataset designed to track solar deployment consistently and at speed — particularly utility-scale facilities that may appear in satellite data ahead of official reporting.

Q4 2025: Key findings

• 1,246 GW detected globally (+5.1% quarter-on-quarter; +34.9% year-on-year)
• 106,800+ facilities mapped worldwide
• 2,085 new sites added in Q4
• 1,660 km² additional solar surface area detected (+5.6%)
• Top five countries account for 71.7% of global capacity

Solar capacity remains concentrated. The top five countries account for 71.7% of detected global capacity, marginally higher than in the previous quarter.

China continues to widen its lead. In 2025 alone, TZ-SAM detected 188 GW of additional capacity — more than five times the additions in the United States. The capacity gap between the two countries expanded from 215 GW to 369 GW within a year. China recorded quarterly growth of at least 7.3% in Q4.

India maintained momentum, expanding by 5.2% quarter-on-quarter and 28.4% year-on-year. In contrast, detections suggest Japan’s growth has slowed, with quarterly expansion below 1.0%.

Spotlight: the Philippines and South Africa

The Q4 release also highlights emerging growth markets.

In the Philippines, detected solar capacity reached 3.7 GW by the end of 2025 — a 44.7% year-on-year increase from a low base. Over the past year, TZ-SAM identified major projects, including ACEN’s 60 MW San Manuel solar plant in Pangasinan and Meralco’s 365 MW Terra Solar facility in Nueva Ecija. Both were incorporated into the dataset prior to appearing on widely used public mapping platforms.

TZ-SAM estimates broadly align with Philippine Department of Energy disclosures, which reported 3.4 GW of installed solar capacity as of July 2025.

In South Africa, where the power system continues to face reliability challenges, detected solar capacity reached an estimated 6.4 GW by year-end. The dataset spans rooftop systems of around 0.3 MW to utility-scale projects approaching 400 MW, alongside concentrated solar power facilities identifiable by their distinctive satellite signatures.

Notable projects identified in 2025 include:

• 273 MW Grootfontein solar plant (Western Cape), operational from December 2025
• 240 MW Mooi Plaats solar project (Northern Cape), under construction

Looking back on 2025

The Q4 release completes four full quarterly cycles in 2025 — a milestone year for TZ-SAM.

Across the year:

• Detected global installed solar capacity grew by 34.9%
• Total mapped solar surface area expanded by 35.8%
• Production timelines fell from more than 60 days to under 15 days per release
• TZ-SAM issued its first commercial licences

Throughout 2025, TZ-SAM identified installations months before they appeared in corporate disclosures, national statistics or public mapping services. The team also piloted new approaches to estimate distributed and rooftop solar capacity, producing initial estimates for Pakistan and several Southeast Asian markets using higher-resolution imagery and extrapolation techniques.

With faster production cycles and growing commercial uptake, TZ-SAM enters 2026 with a stronger operational foundation and a clearer role within the global solar data ecosystem.

Access and next release

TZ-SAM data is published retrospectively, with data for the preceding quarter delivered in the current quarter.

The dataset is open-access under a Creative Commons licence for non-commercial use. Commercial licensing is available for select partners.

Users who register for quarterly release updates receive new data directly in their inbox.

About TransitionZero

TransitionZero is a climate analytics non-profit founded in 2020. We build open-source software and data products that reduce the time to build clean energy at scale. Our flagship tool, Scenario Builder, enables policymakers, planners and investors to analyse electricity systems without coding expertise, supported by model-ready datasets, training and market insights. Since launching publicly in October 2025, Scenario Builder spans 15 countries and supports around 800 users across our modelling and data products. TransitionZero is entirely grant-funded by leading climate philanthropies, including Quadrature Climate Foundation, Google.org, Sequoia Climate Foundation, Bloomberg Philanthropies and the European Climate Foundation. For more information, contact us.