Abstract
Despite comparable solar irradiation and strong economic capacity, Denmark, Finland, Norway, and Sweden exhibit markedly different solar photovoltaics (PV) deployment trajectories. By 2025, Denmark and Sweden had each surpassed 5 GW of installed PV capacity, while Finland and Norway had only recently reached 1 GW. This paper explains these divergent outcomes by comparing market dimensions, energy resource endowments, and policy development across these four Nordic countries. Secondary data on PV deployment, electricity prices, cost of capital, energy mixes, and policy instruments shows that differences in solar diffusion cannot explain the different deployment rates. Instead, deployment patterns are strongly shaped by policy design, timing, and stability, and by how PV competes with incumbent low-carbon resources. Countries with early, generous, but unstable support schemes experienced rapid yet volatile growth, while more gradual and predictable policy frameworks enabled steadier expansion. Further, high end-user electricity prices and access to low-cost capital have favored distributed, self-consumption-oriented PV, whereas weak incentives and complex permitting have constrained utility-scale deployment. These findings highlight how accountable energy governance—through clear targets, stable policy frameworks, and limited politicization—conditions solar PV diffusion in wealthy latecomer countries. The identified key dynamics are broadly applicable to wealthy latecomers in national energy transitions.