The role and meaning of renewable energies for mitigating climate change are usually analyzed along two lines: the bottom-up and the top-down approach. The bottom-up approach focuses on the specific properties of the different renewable energy technologies currently available. The top-down approach focuses on the possible extent of deployment of these technologies and their potential contribution to greenhouse gas emission reductions within an assumed economic development pathway.
To bring the two research communities together, the IPCC has set up an expert meeting on ‘Modeling Renewable Energies’. The meeting was held 30-31 August 2009 in Oslo and gathered renowned experts from both modeling communities, amongst them many authors from the Special Report on Renewable Energy Sources and Climate Mitigation. One of the main goals achieved over the course of the expert meeting was agreement on intensified iterative communication between the two research communities.
On the one hand, top-down modelers will reveal their key assumptions concerning important input parameters for their models. Bottom-up modelers, on the other hand, agreed to critically review these model assumptions and assess the feasibility of the model outcomes. This iterative approach will ensure an ever improving consistency between model outputs and is a crucial step for both the Special Report and the longer-term cooperation process within the IPCC’s Fifth Assessment Report.
Following the Expert Meeting, the lead authors of the Special Report on Renewable Energy Sources and Climate Change Mitigation further outlined its structure. The report aims to answer key questions regarding the role of renewables in a coordinated climate protection effort. In particular, these questions address the contribution of renewable energies in a future with high energy demand or potential resource limitations and the role of Carbon Dioxide Capture and Storage (CCS) and nuclear energy in achieving ambitious climate protection goals. Conditions under which the combined deployment of CCS and biomass energy may become imperative are also addressed.
A main goal of the Special Report to be published in late 2010 is to provide a comprehensive, technology specific assessment of the most important renewable energies, discussing both the challenges of integrating these technologies into the existing energy system and estimating the associated costs in the context of different climate protection goals. In addition, the report will identify different policies that can facilitate the application of renewable energies.
