This month the IPCC will release its Special Report on Renewable Energy Sources and Climate Change Mitigation. For now, only the Summary for PolicyMakers (SPM) is available; the full report will follow May 31st.
From the Press Release:
Ramon Pichs, Co-Chair of the Working Group III: “The report shows that it is not the availability of the resource, but the public policies that will either expand or constrain renewable energy development over the coming decades. Developing countries have an important stake in this future—this is where most of the 1.4 billion people without access to electricity live yet also where some of the best conditions exist for renewable energy deployment.”
This is also where the impacts of climate change are expected to be most severe.
While the report concludes that the proportion of renewable energy will likely increase even without enabling policies, past experience has shown that the largest increases come with concerted policy efforts.
Though in some cases renewable energy technologies are already economically competitive, the production costs are currently often higher than market energy prices. However, if environmental impacts such as emissions of pollutants and greenhouse gases were monetized and included in energy prices, more renewable energy technologies may become economically attractive.
For most of them, costs have declined over the last decades and the authors expect significant technical advancements and further cost reductions in the future, resulting in a greater potential for climate change mitigation.
Public policies that recognize and reflect the wider economic, social and environmental benefits of renewable energies, including their potential to cut air pollution and improve public health, will be key for meeting the highest renewables deployment scenarios.
This has been discussed on this and other blogs (e.g. Kloor’s) a lot. I think by emphasizing multiple benefits the support for renewable energy can increase. Note however that while there are strong synergies between energy policy and climate policy, they are not necessarily identical (and sometimes even opposite in their effects on climate). Nor is energy the only issue to tackle in order to mitigate climate change (carbon storage in forests and soils being another biggie, while the non-CO2 greenhouse gases have mostly non-energetic sources)
Increasing the share of renewables requires additional short-term and long-term integration efforts. Studies clearly show that combining different variable renewable sources, and resources from larger geographical areas, will be beneficial in smoothing the variability and decreasing overall uncertainty for the power system.
There is a need for advanced technologies to optimize the infrastructure capacity for renewables. Additionally, there is a need for balancing supply and demand, like advanced demand and supply forecasting and plant scheduling.
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 co-products.
Key Renewable Energy Technologies and Their Potential
Bioenergy technologies can generate electricity, heat and fuels from a range of ‘feedstocks’.
Some bioenergy systems, including ones that involve converting land into agricultural biomass and energy crops, can generate more greenhouse gas emissions than they save. But others, such as advanced conversion systems, which for example convert woody wastes into liquid fuels, can deliver 80 percent to 90 percent emission reductions compared to fossil fuels. Bioenergy, mainly for traditional cooking and heating in developing countries, currently represents over 10 percent of global energy supply or ca. 50 Exajoules per year. While the share of bioenergy in the overall renewables mix is likely to decline over the coming decades, it could supply 100 to 300 Exajoules of energy by 2050, the expert review concludes.
Direct Solar Energy technologies include photovoltaics and concentrating solar power (CSP). They can produce electricity, heat and light.
Currently, direct solar contributes only a fraction of one percent to total global energy supply. Potential deployment scenarios range from a marginal role of direct solar energy in 2050 to one of the major sources of energy supply. The actual deployment will depend on continued innovation, cost reductions and supportive public policies. In the most ambitious climate stabilization scenarios solar primary energy supply by 2050 reaches up to 130 Exajoules per year, which can be attributed to a large extent to photovoltaic electricity generation. In some scenarios, its share in global electricity generation reaches up to a third by 2050, but in the majority of scenarios remains below one tenth.
Geothermal Energy utilizes heat stored in the Earth’s interior directly or to generate electricity, with currently about 0.7 Exajoule per year.
By 2050, geothermal deployment could meet more than 3 percent of global electricity demand and about 5 percent of the global heat demand. Global geothermal technical potential is comparable to the global primary energy supply in 2008. However, Geothermal Energy does not reach the technical potential limit in any of the scenarios analyzed, with the deployment rate remaining below 5 percent for both the regional and global level.
Hydropower projects encompass dam projects with reservoirs, run-of-river and in-stream projects and range from small to large scale.
The installed capacity by the end of 2008 contributed 16 percent of worldwide electricity supply, making hydropower the largest renewable energy source in the electricity sector. According to long term scenarios, hydropower’s share in global electricity supply may decrease to 10 to 14 percent. Despite absolute growth in hydropower supply, the expected energy demand growth and continuing electrification could result in a decreasing share.
Ocean Energy technologies are diverse and use the kinetic, thermal, and chemical energy of seawater.
Most are at the demonstration and pilot project phases. Due to its nascent stage of development, they are unlikely to significantly contribute to global energy supply before 2020. Ocean energy is currently only represented in very few scenarios. As shown by the review, projected deployments could result in energy delivery of up to 7 Exajoules per year by 2050.
Wind Energy’s primary application of relevance to climate change mitigation is to produce electricity from large wind turbines located on land or offshore.
The wind power capacity installed by the end of 2009 met close to two percent of worldwide electricity demand. The review shows a high expansion rate in Europe, North America and, more recently, inChinaandIndia. A greater geographical distribution of deployment is likely to be needed to achieve the higher deployments indicated by the scenario literature. Under the demand projection of some scenarios global wind power share grows to more than 20 percent by 2050.
Challenges remain (SPM):
A variety of technology-specific challenges (in addition to cost) may need to be addressed to enable RE [renewable energy] to significantly upscale its contribution to reducing GHG emissions. For the increased and sustainable use of bioenergy, proper design, implementation and monitoring of sustainability frameworks can minimize negative impacts and maximize benefits with regard to social, economic and environmental issues. For solar energy, regulatory and institutional barriers can impede deployment, as can integration and transmission issues. For geothermal energy, an important challenge would be to prove that enhanced geothermal systems (EGS) can be deployed economically, sustainably and widely. New hydropower projects can have ecological and social impacts that are very site specific, and increased deployment may require improved sustainability assessment tools, and regional and multi-party collaborations to address energy and water needs. The deployment of ocean energy could benefit from testing centres for demonstration projects, and from dedicated policies and regulations that encourage early deployment. For wind energy, technical and institutional solutions to transmission constraints and operational integration concerns may be especially important, as might public acceptance issues relating primarily to landscape impacts.