Abstract

Over the past five years, installed renewable capacity has doubled across the economies we studied, while the marginal cost of new solar generation has fallen below every fossil alternative. Drawing on hourly grid data from 31 countries, this investigation traces how renewables moved from the fringe of power systems to their centre — and identifies the three bottlenecks that now determine the pace of transition: transmission, permitting, and seasonal storage.

We find that systems reaching 40% variable renewable share required a distinct institutional playbook. Countries that paired auctions with grid investment outperformed those that relied on subsidies alone by a wide margin.

Methodology

The study combines plant-level generation records (2019–2024), levelized-cost estimates from independent auditors, and structured interviews with 46 grid operators. Results were stress-tested against three counterfactual policy scenarios and reviewed by an independent panel of energy economists.

Citations

1. [1]International Energy Agency, World Energy Outlook 2024, Paris, 2024.
2. [2]Santos, M. & Raman, P., “The Economics of Grid-Scale Storage,” Global Research Quarterly, 12(3), 2023.
3. [3]IPCC, AR6 Synthesis Report: Mitigation Pathways, Geneva, 2023.