Summary for Policymakers

This Summary for Policymakers was formally approved at the 11th Session of Working Group III of the IPCC, Abu Dhabi, United Arab Emirates. 5-8 May 2011.

1. Introduction
2. Renewable energy and climate change
　Demand for energy and associated services, to meet social and economic development and improve human welfare and health, is increasing.
　GHG emissions resulting from the provision of energy services have contributed significantly to the historic increase in atmospheric GHG concentrations.
　Recent data confirms that consumption of fossil fuels accounts for the majority of global anthropogenic GHG emissions.
　There are multiple options for lowering GHG emissions from the energy system while still satisfying the global demand for energy services.
　As well as having a large potential to mitigate climate change, RE can provide wider benefits.
　Under most conditions increasing the share of RE in the energy mix will require policies to stimulate changes in the energy system.
3. Renewable energy technologies and markets
　RE comprises a heterogeneous class of technologies (Box SPM.1).
　On a global basis, it is estimated that RE accounted for 12.9% of the total 492 Exajoules (EJ) of primary energy supply in 2008 (Box SPM.2) (Figure SPM.2).
　Deployment of RE has been increasing rapidly in recent years (Figure SPM.3).
　The global technical potential7 of RE sources will not limit continued growth in the use of RE.
　Climate change will have impacts on the size and geographic distribution of the technical potential for RE sources, but research into the magnitude of these possible effects is nascent.
　The levelized cost of energy for many RE technologies is currently higher than existing energy prices, though in various settings RE is already economically competitive.
　The cost of most RE technologies has declined and additional expected technical advances would result in further cost reductions.
　A variety of technology-specific challenges (in addition to cost) may need to be addressed to enable RE to significantly upscale its contribution to reducing GHG emissions.
4. Integration into present and future energy systems
　Various RE resources are already being successfully integrated into energy supply systems [8.2] and into end-use sectors [8.3] (Figure SPM.7).
　The characteristics of different RE sources can influence the scale of the integration challenge.
　Integrating RE into most existing energy supply systems and end-use sectors at an accelerated rate -- leading to higher shares of RE -- is technologically feasible, though will result in a number of additional challenges.
　The costs and challenges of integrating increasing shares of RE into an existing energy supply system depend on the current share of RE, the availability and characteristics of RE resources, the system characteristics, and how the system evolves and develops in the future.
　There are multiple pathways for increasing the shares of RE across all end-use sectors. The ease of integration varies depending on region, characteristics specific to the sector and the technology.
　The costs associated with RE integration, whether for electricity, heating, cooling, gaseous or liquid fuels, are contextual, site-specific and generally difficult to determine.
　In order to accommodate high RE shares, energy systems will need to evolve and be adapted [8.2, 8.3].
　As infrastructure and energy systems develop, in spite of the complexities, there are few, if any, share of total energy demand in locations where suitable RE resources exist or can be supplied. However, the actual rate of integration and the resulting shares of RE will be influenced by factors, such as costs, policies, environmental issues and social aspects.
5. Renewable energy and sustainable development
　Historically, economic development has been strongly correlated with increasing energy use and growth of GHG emissions and RE can help decouple that correlation, contributing to sustainable development (SD).
　　RE can contribute to social and economic development.
　　RE can help accelerate access to energy, particularly for the 1.4 billion people without access to electricity and the additional 1.3 billion using traditional biomass.
　　RE options can contribute to a more secure energy supply, although specific challenges to integration must be considered.
　　In addition to reduced GHG emissions, RE technologies can provide other important environmental benefits. Maximizing these benefits depends on the specific technology, management, and site characteristics associated with each RE project.
　　　Lifecycle assessments (LCA) for electricity generation indicate that GHG emissions from RE technologies are, in general, significantly lower than those associated with fossil fuel options, and in a range of conditions, less than fossil fuels employing CCS.
　　　Most current bioenergy systems, including liquid biofuels, result in GHG emission reductions, and most biofuels produced through new processes (also called advanced biofuels or next generation biofuels) could provide higher GHG mitigation. The GHG balance may be affected by land use changes and corresponding emissions and removals.
　　　The sustainability of bioenergy, in particular in terms of life cycle GHG emissions, is influenced by land and biomass resource management practices.
　　　RE technologies, in particular non-combustion based options, can offer benefits with respect to air pollution and related health concerns [9.3.4.3, 9.4.4.1].
　　　Water availability could influence choice of RE technology.
　　　Site specific conditions will determine the degree to which RE technologies impact biodiversity.
　　　Renewable energy technologies have low fatality rates.
6. Mitigation potentials and costs
　A significant increase in the deployment of RE by 2030, 2050 and beyond is indicated in the majority of the 164 scenarios reviewed in this Special Report.
　RE can be expected to expand even under baseline scenarios.
　RE deployment significantly increases in scenarios with low GHG stabilization concentrations.
　Many combinations of low-carbon energy supply options and energy efficiency improvements can contribute to given low GHG concentration levels, with RE becoming the dominant lowcarbon energy supply option by 2050 in the majority of scenarios.
　The scenario review in this Special Report indicates that RE has a large potential to mitigate GHG emissions.
　Scenarios generally indicate that growth in RE will be widespread around the world.
　Scenarios do not indicate an obvious single dominant RE technology at a global level; in addition, the global overall technical potentials do not constrain the future contribution of RE.
　Individual studies indicate that if RE deployment is limited, mitigation costs increase and low GHG stabilization concentrations may not be achieved.
　A transition to a low-GHG economy with higher shares of RE would imply increasing investments in technologies and infrastructure.
7. Policy, implementation and financing
　An increasing number and variety of RE policies - motivated by many factors - have driven escalated growth of RE technologies in recent years [1.4, 11.2, 11.5, 11.6].
　Policies have promoted an increase in RE capacity installations by helping to overcome various barriers. [1.4, 11.1, 11.4, 11.5, 11.6].
　Public resesarch and development (R&D) investments in RE technologies are most effective when complemented by other policy instruments, particularly deployment policies that simultaneously enhance demand for new technologies.
　Some policies have been shown to be effective and efficient in rapidly increasing RE deployment. However, there is no one-size-fits-all policy.
　‘Enabling’ policies support RE development and deployment.
　Two separate market failures create the rationale for the additional support of innovative RE technologies that have high potential for technological development, even if an emission market (or GHG pricing policy in general) exists.
　The literature indicates that long-term objectives for RE and flexibility to learn from experience would be critical to achieve cost-effective and high penetrations of RE.
8. Advancing knowledge about renewable energy

Figure SPM.2 | Shares of energy sources in total global primary energy supply in 2008(492 EJ) Modern biomass contributes 38% of the total biomass share. [Figure 1.10, 1.1.5]. Notes: Underlying data for figure has been converted to the ‘direct equivalent’ method of accounting for primary energy supply [Box SPM.2, 1.1.9, Annex II]. Figure SPM.3 | Historical development of global primary energy supply from renewable energy from 1971 to 2008 [Figure 1.12, 1.1.5]. Notes: Technologies are referenced to separate vertical units for display purposes only. Underlying data for figure has been converted to the ‘direct equivalent’ method of accounting for primary energy supply [Footnote 1, 1.1.9, Annex II], except that the energy content of biofuels is reported in secondary energy terms (the primary biomass used to produce the biofuel would be higher due to conversion losses [2.3, 2.4]). Figure SPM.4 | Ranges of global technical potentials of renewable energy sources derive from studies presented in Chapters 2 through 7. Biomass and solar are shown as primary energy due to their multiple uses; note that the figure is presented in logarithmic scale due to the wide range of assessed data [Figure 1.17, 1.2.3]. Notes: Technical potentials reported here represent total worldwide potentials for annual renewable energy supply and do not deduct any potential that is already being utilized. Note that RE electricity sources could also be used for heating applications, whereas biomass and solar resources are reported only in primary energy terms but could be used to meet various energy service needs. Ranges are based on various methods and apply to different future years; consequently, the resulting ranges are not strictly comparable across technologies. For the data behind Figure SPM.4 and additional notes that apply, see Chapter 1 Annex, Table A.1.1 (as well as the underlying chapters). Figure SPM.5| Range in recent levelized cost of energy for selected commercially available RE technologies in comparison to recent non-renewable energy costs. Technology subcategories and discount rates were aggregated for this figure. For related figures with less or no such aggregation, see [1.3.2, 10.5, Annex III]. Figure SPM.6 | Selected experience curves in logarithmic scale for (a) the price of silicon PV modules and onshore wind power plants per unit of capacity; and (b) the cost of sugarcane-based ethanol production [data from Figure 3.17, 3.8.3, Figure 7.20, 7.8.2, Figure 2.21, 2.7.2]. Notes: Depending on the setting, cost reductions may occur at various geographic scales. The country-level examples provided here derive from the published literature. No global dataset of wind power plant prices or costs is readily available. Reductions in the cost or price of a technology per unit of capacity understate reductions in the levelized cost of energy of that technology when performance improvements occur [7.8.4, 10.5]. Figure SPM.8. | Estimates of lifecycle GHG emissions (g CO2-eq / kWh) for broad categories of electricity generation technologies, plus some technologies integrated with CCS. Land-use related net changes in carbon stocks (mainly applicable to biopower and hydropower from reservoirs) and land management impacts are excluded; negative estimates10 for biopower are based on assumptions about avoided emissions from residues and wastes in landfill disposals and coproducts. References and methods for review are reported in Annex II. The number of estimates is greater than the number of references because many studies considered multiple scenarios. Numbers reported in parentheses pertain to additional references and estimates that evaluated technologies with CCS. Distributional information relates to estimates currently available in LCA literature, not necessarily to underlying theoretical or practical extrema, or the true central tendency when considering all deployment conditions. [Figure 9.8, 9.3.4.1] Figure SPM.9 | Global RE primary energy supply (direct equivalent) from 164 long-term scenarios versus fossil and industrial CO2 emissions in 2030 and 2050. Colour coding is based on categories of atmospheric CO2 concentration stabilization levels which are defined consistently with those in AR4. The panels to the right of the scatterplots show the deployment levels of RE in each of the atmospheric CO2 concentration categories. The thick black line corresponds to the median, the coloured box corresponds to the inter-quartile range (25th to 75th percentile) and the ends of the white surrounding bars correspond to the total range across all reviewed scenarios. The grey crossed lines show the relationship in 2007. Note that categories V and above are not included and category IV is extended to 600ppm from 570ppm, because all stabilization scenarios lie below 600ppm CO2 in 2100 and because the lowest baselines scenarios reach concentration levels of slightly more than 600ppm by 2100. [Figure 10.2, 10.2.2.2] Notes: For data reporting reasons only 161 scenarios are included in the 2030 results shown here, as opposed to the full set of 164 scenarios. RE deployment levels below those of today are a result of model output and differences in the reporting of traditional biomass. For details on the use of the ‘direct equivalent’ method of accounting primary energy supply and the implied care needed in the interpretation of scenario results see Box SPM.2. Figure SPM.10. | Global RE primary energy supply (direct equivalent) by source in the group of Annex I (AI) and the group of Non-Annex I (NAI) countries in 164 long-term scenarios by 2030 and 2050. The thick black line corresponds to the median, the coloured box corresponds to the interquartile range (25th to 75th percentile) and the ends of the white surrounding bars correspond to the total range across all reviewed scenarios. [Figure 10.8, 10.2.2.5] Notes: For details on the use of the ‘direct equivalent’ method of accounting primary energy supply and the implied care needed in the interpretation of scenario results see Box SPM.2. More specifically, the ranges of secondary energy provided from bioenergy, wind energy and direct solar energy can be considered of comparable magnitude in their higher penetration scenarios in 2050. Ocean energy is not presented here as only very few scenarios consider this RE technology. Figure SPM.11. | Global primary energy supply (direct equivalent) of bioenergy, wind, direct solar, hydro, and geothermal energy in 164 long-term scenarios in 2030 and 2050, and grouped by different categories of atmospheric CO2 concentration level which are defined consistently with those in AR4. The thick black line corresponds to the median, the coloured box corresponds to the inter-quartile range (25th to 75th percentile) and the ends of the white surrounding bars correspond to the total range across all reviewed scenarios. [Excerpt from Figure 10.9, 10.2.2.5] Notes: For details on the use of the ‘direct equivalent’ method of accounting primary energy supply and the implied care needed in the interpretation of scenario results see Box SPM.2. More specifically, the ranges of secondary energy provided from bioenergy, wind energy and direct solar energy can be considered of comparable magnitude in their higher penetration scenarios in 2050. Ocean energy is not presented here as only very few scenarios consider this RE technology. Note that categories V and above are not included and category IV is extended to 600ppm from 570ppm, because all stabilization scenarios lie below 600ppm CO2 in 2100 and because the lowest baselines scenarios reach concentration levels of slightly more than 600ppm by 2100. IPCC（HP/2011/5）による『Special Report on Renewable Energy Sources and Climate Change Mitigation（SRREN）』から