Party preferences for climate policy and the renewable energy transition in Spain's multilevel democracy

Spain’s decentralized ‘State of Autonomies’ allocates shared competencies over climate change and the energy transition between the central state and Autonomous Communities, enabling regions to adopt their own policies and to participate in national initiatives. Building on Climate Federalism, decentralization can foster experimentation, mutual learning, compensatory action, and regionally tailored strategies for the renewable energy transition (RET). These institutional features create incentives for parties that advocate more regional autonomy to highlight climate and RET. The study asks whether pro-decentralization parties give more salience to climate change and renewable energy in national election manifestos. It examines Spanish general elections in June 2016, November 2019, and July 2023 and advances two hypotheses: (1) the salience of climate content in national party manifestos increases with a party’s pro-decentralization stance; (2) the salience of renewable energy content increases with a party’s pro-decentralization stance.

A broad literature on Climate Federalism identifies advantages of decentralization for climate and energy policy, including policy experimentation across levels, horizontal and vertical diffusion, and compensatory action by subnational governments during periods of national inaction. Decentralized systems can enable locally adapted solutions, facilitate decentralized energy systems that improve access and reduce emissions, and enhance legitimacy and public acceptance through proximity and participation, advancing ‘energy democracy’. Renewable energy cooperatives have supported RET and increasingly engage in subnational energy governance. Parallel work on territorial politics and ‘Green Nationalism’ shows minority nationalist and regionalist parties linking environmental goals to autonomy claims (e.g., SNP, ERC, BNG), with evidence that substate climate ambition correlates with demands for regional self-government. Prior studies in Spain and elsewhere suggest pro-decentralization actors may pioneer climate policy and leverage RET’s decentralized production potential to argue for regional energy autonomy.

The study combines qualitative and quantitative manifesto analysis for parties winning seats in Spain’s general elections of June 2016, November 2019, and July 2023. Qualitatively, it first assessed whether and how climate change and energy transition were structurally integrated (dedicated sections vs. transversal mentions) in each manifesto. Quantitatively, it hand-coded 49,816 quasi-sentences, following Schmitt and Wüst’s approach, and adopted Carter et al.’s climate policy coding scheme. A four-category variable classified each quasi-sentence as pro-climate, anti-climate, neutral, or not sufficiently relevant for net GHG emissions. A second variable disaggregated pro-climate content into subcategories (pro-environment, pro-lower carbon transport, pro-energy efficiency, pro-carbon sinks, planning, agriculture and food, waste) and anti-climate content into subcategories (pro-roads, pro-aviation and shipping, pro-fossil fuels, anti-environmental regulation, pro-global free trade, pro-intensive agriculture, pro-tourism, anti-growth, and other). Climate salience was computed as the share of pro- plus anti-climate quasi-sentences. The key subcategory for RET was ‘pro-renewable energy’, defined as advocacy for shifting electricity production, distribution, and consumption from fossil to renewable sources. The main independent variable captured parties’ center–periphery positions: for 2023, hand-coded differences between quasi-sentences favoring decentralization vs. centralization in each manifesto; for 2016 and 2019, an additional positional measure used the MRG/CMP/MARPOR ‘Decentralization’ minus ‘Centralization’ indices. Parties were categorized as Statewide Parties (SWPs) or Non-Statewide Parties (NSWPs). The analysis plotted party scores and assessed correlations descriptively. MP-E was excluded in a robustness step due to extreme climate salience values that distorted patterns. Data are available on request from the author.

- Structural manifesto analysis shows increasing comprehensiveness of climate and energy content across cycles, though placement varies (dedicated sections vs. broader environmental chapters). In 2016, ECP, CMP, EM and Cs had explicit sections; in 2019, MP-E was most thorough, with CMP and ECP also dedicating independent sections; by 2023, Unite, BNG, ERC, PSOE, PP, EAJ-PNV, JxC, and EHB included substantial energy and/or climate content. - Table-based percentages indicate strong ‘pro-climate’ emphasis overall, peaking in 2019. Parties standing out for pro-climate content include CMP, UP, EM, Cs (2016); MP-E, CMP, EHB, TE, UP, EAJ-PNV (2019); Unite, EAJ-PNV, BNG, PSOE (2023). Conversely, PP and VOX frequently register higher ‘anti-climate’ shares (with PRC, TE in 2019 and UPN in 2023 sometimes surpassing them for specific categories). - Pro-climate subcategory emphasis generally prioritizes ‘pro-environment’, followed by ‘pro-lower carbon transport’, ‘pro-renewable energy’, and ‘pro-carbon sinks’. Notable patterns include CMP, UP, Cs emphasizing these in 2016; MP-E and UP in 2019; and in 2023, Unite mirroring UP’s earlier emphasis, with strong ‘pro-renewable energy’ salience for EAJ-PNV and BNG. - Anti-climate subcategories show PP’s 2016 focus on ‘pro-growth’; in 2019, PP, VOX, JxC, and EAJ-PNV share higher anti-climate salience; CC-NC and TE emphasize ‘pro-aviation & shipping’ and ‘pro-roads’ respectively; by 2023, PP and VOX increase ‘pro-fossil fuels’ content. - Hypothesis 1 supported: Scatterplots (Figs. 1–2) show a positive association between a party’s pro-decentralization stance and overall climate salience. NSWPs (most pro-decentralization) consistently display the highest climate salience values. Illustrative manifesto excerpts demand transfers of climate-related revenues and competencies to ACs and municipalities. - Hypothesis 2 supported: Scatterplots (Figs. 3–4) show a positive association between pro-decentralization and the salience of ‘pro-renewable energy’. NSWPs dominate this category in 2023 (e.g., EAJ-PNV, BNG, UPN). Manifestos highlight regional renewable potential (wind, solar, green hydrogen), job creation, and call for decentralized generation close to consumption points while criticizing recentralizing state actions. - While left–right ideology shapes patterns (e.g., left parties often more pro-climate), pro-decentralization position explains additional variance; NSWPs, including some center-right regionalists (e.g., EAJ-PNV), often prioritize climate/RET more than many SWPs, supporting the center–periphery interpretation.

Findings substantiate that in Spain’s multilevel system, parties with stronger pro-decentralization preferences allocate greater attention to climate change and to the renewable energy transition in national manifestos. This pattern holds across cycles and is clearest among NSWPs, which pair policy advocacy with demands for substate competencies and revenues. The results align with Climate Federalism: decentralization fosters policy learning, local tailoring, legitimacy, and compensatory climate action. They also fit ‘Green Nationalism’ arguments: regionalist and nationalist parties strategically link climate and RET to strengthen claims for autonomy and to reshape the territorial distribution of authority over emerging renewable infrastructures. Exceptions (e.g., PSOE’s relatively lower climate salience in 2016–2019; center-right EAJ-PNV’s high pro-renewables salience) show ideology interacts with, but does not fully determine, climate positioning when center–periphery incentives are strong. Overall, the evidence indicates that competition on the center–periphery dimension channels parties—especially NSWPs—toward climate leadership narratives and pro-renewable agendas that promise regional economic benefits and energy self-reliance.

The study demonstrates that pro-decentralization parties prioritize climate change and the renewable energy transition in Spain’s national election manifestos, with NSWPs consistently leading in both climate and pro-renewable salience. This bridges debates on Climate Federalism and Green Nationalism, highlighting how multilevel governance and territorial competition elevate climate issues at the national level. By documenting positive associations between decentralization stances and climate/RET content across three electoral cycles, the paper underscores decentralization’s potential to enhance the efficiency, responsiveness, and legitimacy of climate governance. Future research could: (1) move from descriptive correlations to causal inference; (2) compare Spain with other multilevel democracies; (3) analyze longitudinal within-party changes; (4) link manifesto salience to enacted policies and outcomes; and (5) more finely distinguish the roles and strategies of SWPs versus NSWPs across regions and policy sectors.

- The analysis is descriptive; no causal identification or formal inferential statistics are presented. - One party (MP-E) was excluded in the final phase due to outlier climate salience, which may affect general patterns. - For 2023, decentralization positions rely on hand-coding because standard datasets lacked full coverage; this may introduce measurement error compared with MRG/CMP/MARPOR-based measures used for 2016–2019. - Manifesto-based salience may not translate directly into policy implementation; it captures rhetorical priorities rather than realized outputs. - Very short manifestos can inflate proportional salience of certain categories, complicating cross-party comparisons. - The focus on Spain and on three election cycles limits generalizability across countries and time.