Solar photovoltaics

State of the art (2026)

Solar PV is now the cheapest electricity source ever built, and scale keeps compounding: 2025 added roughly 698 GW (16% growth), pushing cumulative capacity towards 3 TW, with China alone installing about 315 GW. TOPCon has displaced PERC as the mainstream cell, while perovskite-silicon tandems set successive records – LONGi at 34.85% in April 2025 and JinkoSolar at 34.82% in June 2026 – though commercial tandem modules remain pre-volume. The defining tension is supply-chain concentration: China holds roughly 80% of every value-chain step, Tier-1 modules trade near $0.09/W FOB, and structural overcapacity persists. US-delivered modules sit at $0.27–0.32/W as tariffs and a 50 GW-plus domestic build-out reprice the Western market.

Core thesis

Solar panels are the cheapest source of new electricity in most of the world, and more are installed every year. The world added about 510 GW of solar in 2025, of which China added about 315 GW, according to the International Renewable Energy Agency. China also makes about 80% of the panels and of every part that goes into them. JinkoSolar and LONGi ship the most panels, and a price war lasting several years has cut manufacturers' profits. US and EU tariffs raise the cost of installing solar there, and have led to new panel factories in the US. The next improvement is a panel that adds a layer of perovskite on top of silicon to turn more sunlight into power. LONGi holds the efficiency record for it, and Oxford PV is the main Western company working on it.

Perovskite tandem: the next efficiency revolution

Perovskite-silicon tandem cells now set records around 35% – LONGi at 34.85% (April 2025) and JinkoSolar at 34.82% (June 2026, its 33rd certified record) – versus roughly 24% for the best commercial silicon. LONGi's flexible tandem work was named one of China's top-10 scientific advances. The big Chinese makers (LONGi, JinkoSolar, Trina) target volume tandem production around 2027. Oxford PV is the Western leader and has actually been first to ship commercial tandem modules (from late 2024, ~25% module efficiency), with mass production planned for 2027; the open question is 25-year-grade durability, not whether the cell can be built. The West's edge is here, in tandem, not in re-competing on commodity silicon – but China leads on cell efficiency.