The country of perpetual potential: Engineering the solar and geothermal transition in Indonesia

Indonesia holds one of the world’s largest endowments of renewable energy, including some of the greatest geothermal resources on Earth and solar potential that dwarfs national demand. However, renewables supply only a modest share of its electricity, and its 23%-by-2025 target has been missed. This commentary argues that the defining feature of the Indonesian energy transition is a persistent gap between physical potential and deployed capacity, and that this gap is fundamentally an engineering-and-institutions problem rather than a resource issue. Focusing on solar photovoltaics and geothermal energy, I show that the binding constraints are the cost of capital, design of procurement and offtake, grid integration, and policy instability, and that these interact with genuine engineering challenges: subsurface risk and scaling in geothermal, variability and storage in solar, and the extraordinary difficulty of serving demand dispersed across more than seventeen thousand islands. I treat geothermal firmness and solar abundance as complements rather than rivals, and critically examine the tensions that any credible transition strategy must resolve—local-content rules versus deployment speed, the single-buyer utility model, and the promise versus the delivery of international climate finance. I conclude with an agenda that pairs engineering priorities with institutional reforms, without which the potential will remain perpetual.