The Spatial Unevenness of Acceleration Barriers: Grid Integration and Policy Responses in India and Germany's Renewable Energy Transitions

The acceleration of low-carbon energy transitions is critical for achieving climate targets, but system integration challenges threaten to undermine the acceleration of renewables deployment. While it is typically assumed that such barriers affect countries at advanced phases of the transition, there is a limited understanding of when and how they manifest across different geographical and socioeconomic contexts, and what level of policy effort is required to address them. Here, we address this gap by examining the co-evolution of renewables acceleration, system integration challenges, and policy effort across two contrasting socioeconomic contexts: Germany and India, two countries with ambitious renewable energy targets but with different socioeconomic contexts, market and institutional structures, and at different stages of their respective energy transitions. First, we trace the introduction and evolution of policies related to grid integration in both countries, analysing both the amount and design of grid integration policies. Second, we map these policy findings to the “phases of variable renewables (VRE) integration” both countries underwent between 2009-2024. We follow the International Energy Agency’s (IEA) definition, which classifies national energy systems into six phases: from very low levels of VRE deployment (Phase 1) to those where renewables meets almost all annual demand (Phase 6). Our methodology enables precise identification of when system integration challenges begin to be prioritised across contexts and uncovers an interesting phenomenon: integration challenges emerge significantly earlier in developing countries than in transition pacesetters, necessitating earlier policy intervention despite lower overall technology deployment levels. In Germany, system integration was shaped by the complementary expansion of solar and wind power. It entered Phase 2 following a surge in solar additions (2009-2012), which accompanied a marked increase in system integration policies targeting grid expansion and plant retrofitting. Despite a brief deceleration in solar additions, wind growth (2014-2017) pushed the system into Phase 3, triggering electricity market reforms and curtailment regulations. Recently, renewed acceleration in both technologies (2022-2023) advanced Germany into Phase 4, where VRE meets all demand for a few hours annually. On the other hand, India – only in Phase 2 as of 2023 – began introducing integration-focused policies at a much earlier stage of transition. Here, the adoption of VRE went hand-in-hand with market reforms enabling large-scale private participation in electricity generation for the very first time. The first policies addressing curtailment began to be introduced as early as 2010, with negligible solar PV in the system. The emergence and increasing dominance of solar in the following years led to policies targeting ancillary services, cogeneration, storage, and grid expansion already in 2015. This earlier emergence of similar policies challenges assumptions about when system integration challenges become salient and how their timing varies across socioeconomic contexts. Our findings highlight that developing economies facing harder challenges in terms of market and institutional preparedness may require earlier policy interventions than in transition pacesetters.