The Energy [R]evolution 2010 scenario is an update of the Energy [R]evolution scenarios published in 2007 and 2008. It takes up recent trends in global energy demand and production and analyses to which extent this affects chances for achieving climate protection targets. The main target is to reduce global CO 2 emissions to 3.7 Gt/a in 2050, thus limiting global average temperature increase to below 2°C and preventing dangerous anthropogenic interference with the climate system. A ten-region energy system model is used for simulating global energy supply strategies. A review of sector and region specific energy efficiency measures resulted in the specification of a global energy demand scenario incorporating strong energy efficiency measures. The corresponding supply scenario has been developed in an iterative process in close cooperation with stakeholders and regional counterparts from academia, NGOs and the renewable energy industry. The Energy [R]evolution scenario shows that renewable energy can provide more than 80% of the world's energy needs by 2050. Developing countries can virtually stabilise their CO 2 emissions by 2025 and reduce afterwards, whilst at the same time increasing energy consumption due to economic growth. OECD countries will be able to reduce their emissions by up to 90% by 2050. However, without a comprehensive energy efficiency implementation strategy across all sectors, the renewable energy development alone will not be enough to make these drastic emissions cuts.

Research on 100% renewable energy systems is a relatively recent phenomenon. It was initiated in the mid-1970s, catalyzed by skyrocketing oil prices. Since the mid-2000s, it has quickly evolved into a prominent research field encompassing an expansive and growing number of research groups and organizations across the world. The main conclusion of most of these studies is that 100% renewables is feasible worldwide at low cost. Advanced concepts and methods now enable the field to chart realistic as well as cost-or resource-optimized and efficient transition pathways to a future without the use of fossil fuels. Such proposed pathways in turn, have helped spur 100% renewable energy policy targets and actions, leading to more research. In most transition pathways, solar energy and wind power increasingly emerge as the central pillars of a sustainable energy system combined with energy efficiency measures. Costoptimization modeling and greater resource availability tend to lead to higher solar photovoltaic shares, while emphasis on energy supply diversification tends to point to higher wind power contributions. Recent research has focused on the challenges and opportunities regarding grid congestion, energy storage, sector coupling, electrification of transport and industry implying power-to-X and hydrogen-to-X, and the inclusion of natural and technical carbon dioxide removal (CDR) approaches. The result is a holistic vision of the transition towards a net-negative greenhouse gas emissions economy that can limit global warming to 1.5˚C with a clearly defined carbon budget in a sustainable and cost-effective manner based on 100% renewable energy-industry-CDR systems. Initially, the field encountered very strong skepticism. Therefore, this paper also includes a response to major critiques against 100% renewable energy systems, and also discusses the institutional inertia that hampers adoption by the International Energy Agency and the Intergovernmental Panel on Climate Change, as well as possible negative connections to community acceptance and energy justice. We conclude by discussing how this emergent research field can further progress to the benefit of society.

Length Chapter 10 has been allocated a total of 68 pages in the SRREN. The actual chapter length (excluding references & cover page) is 90 pages: a total of 22 pages over target. The Executive Summary exceeds its allocation by 2 pages as it shall not exceed 1.5 pages. Expert reviewers are kindly asked to indicate where the Chapter and Executive Summary could be shortened in terms of text and/or figures and tables. Structure In light of the very successful IPCC WG III Expert Meeting 'Modelling Renewable Energies; Coherence Between Model Assumptions and Latest Technological Knowledge', new data and new literature the structure of Chapter 10 has been improved to follow a more logical order. This new structure is subject to IPCC plenary approval. Please note that all content from the chapter outline has been retained. Expert Reviewers are kindly invited to comment on these amendments. The content of the original 10.2 (Methodological Issues) is now integrated in each relevant subsection, where appropriate. Similarly, the content of the original 10.7 (Gaps in knowledge and uncertainties) now appears at the end of the relevant subsections , where appropriate. The original 10.3 (Assessment and synthesis of scenarios for different renewable energy strategies (top-down and bottom-up)) is shifted to section 10.2 and deals as before with an overview of medium to longterm global, aggregated models. The original section 10.4 (cost curves for mitigation with renewable energy) is split apart into the new sections 10.3 and 10.4. The new 10.3 (Assessment of representative mitigation scenarios for different renewable energy strategies) investigates those models further that have greater technological detail. The new 10.4 (regional cost curves for mitigation with renewable energy) extends on the old 10.4 and goes into further technical detail dealing with regional resource cost curves and mitigation cot curves. References First Order Draft Contribution to Special Report Renewable Energy Sources (SRREN) Do Not Cite or Quote 2 of 106 Chapter 10 SRREN_Draft1_Ch10 22-Dec-09 References highlighted in yellow are either missing or unclear. Tables & Figures The Numbering of tables & figures is not continuous and its structure differs between the numbers attached to the table & figure and the one in the text. That is, numbering of tables & figures starts new with every subsection 10.x and is structured 10.x.1, 10.x.2, … Numbering in the text starts with 1 in every subsection 10.x. Therefore, each reference can be clearly identified by the last digit. For example, in section 10.2, Figure 10.2.5 is referred to as Figure 5 in the text.

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It is still possible to comply with the Paris Climate Agreement to maintain a global temperature ‘well below +2.0 °C’ above pre-industrial levels. We present two global non-overshoot pathways (+2.0 °C and +1.5 °C) with regional decarbonization targets for the four primary energy sectors—power, heating, transportation, and industry—in 5-year steps to 2050. We use normative scenarios to illustrate the effects of efficiency measures and renewable energy use, describe the roles of increased electrification of the final energy demand and synthetic fuels, and quantify the resulting electricity load increases for 72 sub-regions. Non-energy scenarios include a phase-out of net emissions from agriculture, forestry, and other land uses, reductions in non-carbon greenhouse gases, and land restoration to scale up atmospheric CO2 removal, estimated at −377 Gt CO2 to 2100. An estimate of the COVID-19 effects on the global energy demand is included and a sensitivity analysis describes the impacts if implementation is delayed by 5, 7, or 10 years, which would significantly reduce the likelihood of achieving the 1.5 °C goal. The analysis applies a model network consisting of energy system, power system, transport, land-use, and climate models.