The Intergovernmental Panel for Climate Change is a body of the United Nation responsible for studying climate change and designing a global response to it. From time to time, IPCC publishes its latest findings in its annual reports. This Special Report on Renewable Energy Sources and Climate Change Mitigation (SRREN) was designed to assess the potential role of renewable energy in the mitigation of climate change in the private sector, for policymakers, academic researchers, and in civil society. The report mainly concentrates on six major sources of renewable energy–bioenergy, direct solar energy, geothermal energy, hydropower, ocean energy, and wind energy.  It takes into account the integration of these sources of energy in current and future energy systems. And finally, it considers the environmental and social consequences of the utilization of these resources and compares the cost of energy from renewable and non-renewable sources.

Some of the major inferences from this report are described below:

Renewable Energy and Climate Change


With an increase in population, people’s energy needs have also increased significantly. Fossil fuels have largely dominated the energy market, not only are they not sustainable, but they are also the leading cause of carbon dioxide (CO2) emissions into the atmosphere. As of 2010, CO2 concentrations have increased to over 390 ppm or 39% above preindustrial-levels. These Greenhouse Gases (GHS) have been observed to cause a significant rise in the global average temperature and are likely to increase even more.

The aim of this report is to understand how renewable energy can be used to lower GHG emissions, while still meeting the global requirement for energy. Although increasing the share of renewable energy will require policies and changes to the current energy system, there are many wider benefits. If implemented properly, renewable energy can be used to contribute to social and economic development while reducing the negative impacts on the environment.

Renewable Energy Technologies and Markets

There are various renewable energy technologies that can cater to different energy needs. Renewable energy can supply electricity, thermal and mechanical energy, as well as produce fuels that can satisfy energy service needs.  The technologies considered in this report are:


Bioenergy can be produced from organic waste streams and agricultural and livestock residue. The projects usually depend on the local fuel supply and regional fuel supply availability, but recent trends show that biomass and liquid biofuels are being traded internationally as well.

Direct Solar Energy


This technology harasses the energy of solar irradiance to produce electricity using Photovoltaics (PV) and Concentrating Solar Power (CSP). The applications include thermal energy, direct lightning, and the production of fuel.

Geothermal Energy


It utilizes the thermal energy from the Earth’s interior that is extracted from a geothermal reservoir using wells. Once the fluids reach the Earth’s surface, they can be used to generate electricity or for thermal heating applications.



This form harnesses the energy of water moving from higher to lower elevations, to generate electricity. Hydropower projects are able to encompass dam and reservoir projects and this gives them the ability to meet various rural and urban energy needs.

Ocean Energy


The energy is derived from the potential, kinetic, thermal, and chemical energy of seawater. This can be transformed into thermal energy or produce electricity, or portable water.

Wind Energy


This technology harnesses the kinetic energy of moving air to produce electricity using large wind turbines that are either placed on land (onshore) or at sea (offshore). Offshore wind farms have the potential for huge technical advancements.

The report states that in 2008, renewable energy contributed to about 19% of global electricity supply with 16% from coming from hydropower, 2% from biofuels, 17% from traditional biomass, and 8% from modern biomass. Solar thermal and geothermal energy together fuelled 27% of the total global energy demand for heat. These numbers have been rapidly increasing in recent years with the introduction of government policies to reduce the prices of renewable energy, the decreasing cost of renewable energy technology, and the increasing demand for energy being the catalyst for their popularity. In the period from 2008-2009, 140GW of 300GW of new electricity generating capacity came from renewables. The global technical potential of renewable energy sources is considerably higher than the global energy demand, with solar being the highest. This technical potential exists for all six other sources as well.

Integration into Present and Future Energy Systems

Various renewable energy sources are already being successfully integrated into energy supply systems, but the end goal is to integrate renewable energy into all types of energy supply systems, which in turn will increase the shares of renewables to end-use-sectors as well. To do this, the current energy systems will have to be adapted. This will require investments in research, development and demonstration (RD&D) and other supporting measures. However, the actual rate of integration will be influenced by costs, policies, environmental issues, and social aspects.

Renewable Energy and Sustainable Development

Historically, economic development went hand-in-hand with increasing energy use, but this has also led to an increase in GHG emissions. Renewable energy can provide a sustainable alternative to this method. It offers a chance to contribute to various developmental initiatives like social and economic development, energy access, secure energy supply, climate change mitigation, and the reduction of negative environmental and health impacts. It can help provide basic access to energy for the 1.4 billion people without access and an additional 1.3 billion people who are still using traditional biomass.

Mitigation Potentials and Costs

The plausible scenarios outlined in this report show a contribution of renewable energy shares reaching approximately 43% in 2030 and 77% by 2050, but renewable energy can be expected to expand even under baseline scenarios. With the help of low-carbon energy supply options and energy efficiency improvements, renewable energy can become the dominant low-carbon energy supply option by 2050. The scenario review in this Special Report indicates that renewable energy has a large potential to mitigate GHG emissions with its widespread growth around the world. A transition to a low-GHG economy with a higher concentration of renewables will increase investments in technology and infrastructure. The report estimates that renewable energy investments will be between USD 1,360 to 5,100 billion for the decade 2011 to 2020, and from USD 1,490 to 7,180 billion for the decade 2021 to 2030.

Policy, Implementation and Financing


An increasing variety of renewable energy policies have escalated its growth in recent years. These policies include regulations such as feed-in-tariffs, quotas, priority grid access, building mandates, biofuel blending requirements, and bioenergy sustainability criteria. Other policies include tax policies and direct government payments such as rebates and grants. Public research and development (R&D) investments when complemented by other policies enhance the demand for new innovative technologies. Long-term objectives for renewable energy and flexibility to learn from experience would be critical to achieving cost-effective and high penetrations of renewables. This would require the systematic development of policy frameworks that reduce risks and enable returns.

Advancing Knowledge about Renewable Energy

Enhanced scientific and engineering knowledge about renewables will lead to technology improvements and cost reductions. Additional knowledge to be gained relates to future costs and timing of deployment, realizable technical potential, technical challenges and costs of integrating renewable energy into energy systems, assessments of environmental and social aspects, ability to meet the needs of energy demand in developing countries, policy, institutional, and financial mechanisms to enable cost-effective deployment of renewable energy worldwide.


The results presented in this report combine technology-specific studies to help provide policymakers with the technical potential of different renewable energies, the challenges of their integration, and their Levelized cost of energy. The report also discusses the role of renewables in reducing GHG emissions and analyses the policies available to assist the development of renewable energy towards achieving a more sustainable future.

Click here to read the whole report.

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