The global carbon neutrality objective is a key upshot of the Paris Agreement climate goals. Its translation to the national level has been central to climate policy since then and, notably, country commitments have flourished over the years. However, there is still limited scientifically robust and policy-relevant evidence on national pathways to net-zero that captures the specifics of national circumstances. Such insights would be critical to ensure that carbon neutrality pledges are credible and actionable. This paper presents the methodological approach developed under the Deep Decarbonization Pathways (DDP) initiative to support the elaboration by in-country experts of national scenarios exploring long-term transformations consistent with carbon neutrality, and to enable a constructive dialogue on carbon neutrality with a large set of decisionmakers. We present carbon neutrality scenario results for 7 large emerging economies developed with this method. They display how each country can define its own pathway to net-zero, considering its national circumstances and in a way that preserves key domestic socio-economic priorities. They display some country-specific patterns but also highlight key common transformations for carbon neutrality, including moderation of final energy uses, a steady decrease in the use of fossil fuels for all purposes and substitution of low GHG energy forms, and a steady increase in the absorption capacities in diverse land uses. To trigger these net-zero transformations, national public decision makers should evolve national development policy packages according to the three following policy insights.

Coal-based industries represent a critical challenge for long-term energy transitions: their strong economic and energy-security benefits come with the disadvantage of high greenhouse-gas (GHG) emissions. South Africa’s Coal-to-Liquids (CtL) complex in Secunda, which is responsible for around 12 % of national GHG emissions, illustrates these tensions, where rapid or unplanned shutdown could impose substantial economic and energy-security risks. This study evaluates alternative decarbonisation strategies and transition pathways for this CtL complex using an enhanced version of the South African TIMES national energy-system optimisation model. Three pathways are examined: a Baseline case; a Roadmap-Aligned pathway reflecting near-term efficiency with renewable energy integration measures; and a Structural Decarbonisation pathway in which low-carbon technologies are deployed under a national long-term emissions constraint (LTEC).The Roadmap-Aligned scenario reduces facility-level emissions by ∼ 26 % by 2030, decreasing carbon intensity from 0.18 to 0.15 Mt CO2 PJ−1. Structural Decarbonisation under a national Long-Term Emissions Constraint of 8.5 Gt achieves deeper cuts of 45 % by 2030, 56 % by 2040 and 62 % by 2045, ultimately lowering carbon intensity to 0.097 Mt CO2 PJ−1. While a structural transition is feasible, decarbonisation remains partial. Demand-side electrification, especially uptake of electric vehicles, ease fuel demand and CO2 constraints, while transition timing is primarily governed by costs of renewable energy and policy ambition, with oil-price dynamics playing a secondary role. Lower oil prices narrow profit margins and reduce Fischer–Tropsch output and Scope 1 emissions, yet result in earlier hydrogen deployment, whilst higher oil prices have the opposite effect. The findings provide strategic insights for policymakers and planners designing industrial transition pathways in carbon-intensive economies.

Steel producers in the Global South face increasing pressure from trade and required emissions cuts. Renewable-rich regions could become key suppliers of low-carbon steel, but this vision remains conceptual and risks perpetuating extractivist patterns. Using the Global Energy System Model (GENeSYS-MOD), we assess technological, spatial and employment implications of South Africa’s steel transition. We find that an early push for hydrogen-based capacities is beneficial – but needs to be embedded in a broader just transition framework.

Emerging middle-income countries have indicated a strong commitment towards mitigating their greenhouse gas (GHG) emissions not only through their Nationally Determined Contributions (NDCs) but also by raising their climate ambition and committing to net-zero emissions at COP 26 in Glasgow, as well as to tripling renewables at COP 28. The electric power generation sector plays a crucial role in supporting the sustainable social and economic development of a nation but is also currently one of the largest and growing sources of energy related GHG emissions in major emerging economies. In this study, we analyse current policy and deep decarbonization scenarios of the power sector in four developing middle-income economies (Brazil, India, Indonesia and South Africa). Through retirement of old, inefficient fossil-based power plants and a transformative shift towards non-fossil-based variable and firm primary energy sources the results demonstrate a reduction in carbon intensity to 104 grams CO2//kWh (Indonesia), 96 grams CO2//kWh (India) and 43 grams CO2//kWh (South Africa). To achieve power sector decarbonization a step change increase in policy stringency is required, combined with substantial international financial support through mechanisms like Just Energy Transition Partnerships. This must be combined with necessary market reforms to make these markets self-sustaining for needed investments to meet development, energy security and climate goals.

The practical feasibility of GHG mitigation pathways is increasingly acknowledged as essential to climate scenario development. However, energy system models (ESMs) still lack a structured and comprehensive approach for integrating feasibility considerations. This study proposes a conceptual framework that addresses this gap by guiding the integration of feasibility aspects into model-based scenario studies, with a specific focus on the industrial sector.At the heart of the proposed concept lies the Feasibility Loop—the core contribution of this work. It provides a structured, visual, and process-oriented approach to systematically link existing methods, indicators, and data sources across the entire modelling process. The loop identifies key steps in a model-supported feasibility assessment, clarifies how different types of methods contribute to these steps, and supports modellers in understanding where and how feasibility aspects can be meaningfully integrated.The framework is built around three distinct types of feasibility constraints—hard, quantitative soft, and qualitative soft—which serve as a conceptual bridge between assessment content, modelling tools, and interdisciplinary knowledge. Supporting components include a 5W1H-based structuring of the research context, a typology of feasibility-relevant indicator categories, and guidance for modelling requirements such as granularity and adaptability.Rather than prescribing a fixed workflow, the proposed concept serves as a flexible toolbox, enabling tailored application depending on available resources and research goals. Finally, it aims to improve the relevance, comparability, and transparency of scenario results and support more robust decision-making in the transformation of energy-intensive industry systems.

The currently most promising approach for reducing CO2 emissions of the global steel production is reducing iron ore in shaft furnaces with (green) hydrogen instead of blast furnaces. Unlike to the liquid iron produced in blast furnaces, the direct reduced iron produced in this route (green iron) exists in a solid state and can be transported at reasonable costs over long distances. This allows for spatial decoupling of the iron reduction step from the steelmaking step and may lead to global trade in green iron as a new intermediate product in the steelmaking value chain. This article assesses the potential impact of a global green iron trade in terms of shifting energy demand between regions and in terms of cost savings by comparing three scenarios for a global near-zero GHG steel industry: The Domestic scenario, assuming strict regional co-location of green iron and steel production; The Max Trade scenario, assuming early emergence of a global green iron market and the Intermediate Trade scenario, assuming late emergence of a global green iron market. In the trade scenarios, 12-21% of global crude steel is produced from traded green iron in 2050. 15-26 Mt/a of hydrogen consumption is relocated to global “sweet spots”, resulting in cost savings of 2.2-3.9% of the global annual steel production costs, which can provide important support for the development of net zero steel production. Enablers and barriers for global green iron trade are discussed.

National and international freight transport emissions represent about 40% of global transport emissions, with demand expected to triple by 2050, which will increase emissions further. However, to meet the 1.5 degrees C climate goal, a rapid decrease in transport emissions is required, along with the achievement of zero emissions as soon as possible around mid-century. Given this context, long-term low-emission national development pathways provide a strategic instrument to align short-term action with long-term objectives and to reduce national freight transport emissions. However, current transport-energy modelling studies often exclude the structural and systemic mitigation options that influence the industrial production and supply chain structure, as well as modal and logistics choices, and instead focus mainly on the technological options related to road freight vehicles and fuels. In addition, such studies lack relevant policy and stakeholder-oriented explanations of the barriers and enablers associated with these options. In this paper, we introduce a new framework to design and compare long-term national and sectoral decarbonization pathways for freight transportation, facilitating the consideration of all decarbonization options and the organization of stakeholder-oriented policy dialogues. The development of this sectoral framework builds on the general Deep Decarbonization Pathways (DDP) framework and a first implementation in France. It is then applied and tested in three emerging countries: Brazil, India and South Africa and the results show that the linking of systemic and technological changes could reduce emissions per tonne-km by at least 60%, and up to 100% by 2050, while also reducing energy consumption and supporting national development.

South Africa faces a myriad of energy-related challenges, including severe constraints in electricity supply, a rising cost of electricity to consumers, high levels of energy poverty, and a reliance on coal in both energy supply and demand sectors. These challenges exist in a context of significant development imperatives and commitments to decarbonise. This paper presents the South African TIMES model (SATIM), a comprehensive energy systems model developed and maintained over two decades, which has proved useful in informing energy and climate policy in South Africa. We explore how SATIM has been adapted to overcome data limitations and address unique and complex policy, development and broader socio-economic challenges faced by developing countries. The model's evolution, structure, and applications are discussed, highlighting its role in providing evidence-based insights for critical policy decisions. We argue that SATIM's long-term development, flexibility, and integration with other models offer valuable lessons for energy systems modelling in developing country contexts.

Working with in-country modelling teams and models, targeting net-zero CO2 emissions by later this century, and using decomposition and emissions driver analysis, we develop low emissions cement and steel scenarios linked to usable policy levers for Brazil, India, and South Africa. We find significant mitigation potential from a 'current policy' scenario on the demand side (13-26%) and the production side (58-71%), but these countries' substantial needs for more basic infrastructure - and thus for cement and steel inputs - indicate net-zero will remain very challenging. Demand-side material efficiency reductions, where less steel and cement deliver the same service through better design, will require decades of educational and regulatory efforts, working with buildings sector and infrastructure supply chain actors to reach full potential. In the short to medium run, focusing on reducing emissions from production may deliver more near-term cumulative mitigation by allowing close attention to a small number of domestic companies with high managerial, technical, and financial capacity. To achieve such reductions, governments should encourage the concentration of cement and concrete making at professional facilities to allow the use and regulation of already commercialized lower GHG practices like cementitious material clinker replacement and better concrete mixing while planning for future carbon capture and storage. Governments should also encourage investment in secondary steel making using electric arc furnaces to reuse local recycled scrap, eventually supplemented with increasingly low emission primary iron. International cooperation and support are needed to agree on and implement CO2 intensity accounting systems, improve access to low-emissions production technologies through innovation and commercialization combined with technology transfer or co-development, and offer financial and technical support for clean production investments.Key policy insightsOn the demand side, international buildings organizations and domestic building code regulators should work with architects, structural engineers, and construction companies to implement regionally appropriate material efficiency options.On the production side, international cement and steel organizations, governments and domestic firms should explore cooperation on technology innovation and transfer, finance, and private and public lead market mechanisms, e.g. premia for low emission production and green procurement.Adaptive long-term sectoral strategies addressing demand and supply will need to be developed with all affected parties.

The production of iron and steel is one of the largest global sources of industrial greenhouse gas (GHG) emissions. South Africa (SA) could competitively export near-zero embodied GHG primary iron to steelmakers in leading decarbonizing markets. A green primary iron production process substitutes hydrogen for coke as the iron ore reductant. A SA plant would enjoy most of its competitive cost advantage from hydrogen produced using very low-cost solar photovoltaic electricity. In import markets, using the European Union (EU) as an example, steelmakers could use imported green primary iron to increase utilization of electric arc furnaces while reducing total EU demand for clean electricity (i.e. for hydrogen for reduction needs) and thereby lower total system costs of decarbonization. SA could bolster crucial export and tax revenues while moving towards a broader transition to a sustainable industry. Three things are needed to unlock new global business models involving the relocating of green primary iron production to regions with abundant renewable energy: (1) a steelmaker with access to a hydrogen reduction technology appropriate for SA's ores willing and able to invest in a plant; (2) access to a bankable lead market for that plant's production; and (3) international trade rules and emissions accounting related to the carbon content of commodities that enable the reconfiguration of supply chains to reduce global decarbonization costs. Key policy insights Green primary iron production in SA could increase value added from local iron ore and solar energy resources, bolster exports and initiate transformation to a sustainable industry. Green primary iron imports from SA to the EU could reduce the cost of overall decarbonization while increasing the competitiveness of steel product manufacturing. Enabling conditions include a willing steelmaker, fair access to the EU iron market, enabling trade rules, and embodied emissions certification and accounting. Green primary iron imports can reduce demands on EU low carbon electricity supply, lowering electricity prices and increasing energy security. The collaboration envisioned between the EU and SA could help develop the framework for future inter-regional decarbonization strategies for other commodities and other countries.

South Africa, a signatory to the Paris Agreement, submitted a revised NDC just before COP26, significantly revising its 2025 and 2030 mitigation targets. The revision of the mitigation component of the NDC was informed by two pieces of analysis: the first to establish what would be considered “fair”, and the second to assess what different levels of mitigation target would require nationally, in terms of infrastructure, investment and impact on economic growth and employment. This paper focuses on the second part of the analysis, and presents the approach taken. The analysis makes use of the SATIMGE modelling framework, a partial equilibrium model of the energy system linked to a recursive dynamic general equilibrium model for South Africa, and augmented by modules for other emissions sources. To achieve, the range of CO 2 -eq examined in the “fair share” range (350-420 Mton CO2-eq), and beyond, at the 2030 horizon, most of the mitigation would come from the power sector. To reach higher ambitions of 350 Mton CO2-eq in 2030, would require significant additional investment in new low carbon electricity and retirement of existing coal generation capacity, unless investment in the power sector be allowed to be reoptimized relative to what is in the current policy. Every additional 50Mton CO2-eq requires around an additional $16.8b of investment. The higher ambition level could be achieved without incurring a significant GDP loss in 2030 relative to what is anticipated with the full set of policies are implemented and if the power sector is reoptimized.

In this paper an improved energy-economic model is used to analyse the transition away from coal and toward renewable energy in South Africa. The model enhancements presented in this paper allow for a more accurate assessment of changing coal costs on potential energy and emissions pathways for South Africa. The better representation of the coal sector provides insights on the timing and magnitude of coal mine and power plant retirements, which are a crucial part of information in developing policies required to ameliorate any negative impacts resulting from the energy transition. These negative impacts currently form a social obstacle to change in energy policy. To illustrate the model advances two potential power generation pathways for South Africa are compared: a least-cost energy mix which does not include new coal power plants; and one where renewable capacity in the power sector is constrained, resulting in ~25GW new coal-fired power plant capacity. A comparison of these scenarios shows that, with rising coal costs and lower coal export demand, persisting with coalbased power generation does not “save jobs” in South Africa at the aggregate level, as higher power investment is required in the constrained scenario. This, combined with the higher electricity price experienced in the constrained scenario, negatively affects the rest of the economy, offsetting any positive gains from continued coal-based power generation. Improved Representation of Coal Supply for the Power Sector for South Africa 2 2

Explicitly representing uncertainty is recognised as a fundamental requirement of any long-term forecast. We propose and illustrate an expert elicitation protocol for constructing long-term probabilistic projections. Each projection represents a possible realization of a time series with autocorrelation properties, and thus a plausible future evolution of a quantity of interest. We illustrate the approach using two quantities – GDP growth rates and coal prices – that were elicited as part of a project producing baseline forecasts of greenhouse gas emissions in South Africa to 2050. The elicited projections can be used as inputs to deterministic structural models of the energy, economic, and environmental sectors (e3 or energy-environment-economic models), to generate similar probabilistic projections for any desired outputs of the e3 model. An R package for the generation and visualization of these probabilistic projections is provided.