Historical market projections and the future of silicon solar cells

The International Technology Roadmap for Photovoltaics (ITRPV) is a globally recognized annual report discussing and projecting photovoltaic (PV) industry trends. Over the past decade, the silicon PV manufacturing landscape has undergone several rapid changes. By analyzing ITRPV reports from 2012 to 2023, we highlight some key discrepancies between projected industry trends and estimated actual market share. Some technologies have vastly exceeded the expected trends, e.g., the passivated emitter and rear cell and the use of gallium as the dominant p-type dopant. However, other projections have not occurred as quickly as expected, e.g., adopting silicon heterojunction cells and shifting to n-type wafers. In this work, we provide insights into the fidelity of projected trends by discussing some of the factors causing such rapid technological changes. By reflecting on 10 years of roadmap data, we highlight the fast-moving nature of the PV industry, meaning that business-as-usual projections must be assessed with caution.