Reducing anthropogenic greenhouse gas (GHG) emissions in material quantities, globally, is a critical element in limiting the impacts of global warming. GHG emissions associated with energy extraction and use are a major component of any strategy addressing climate change mitigation. Non-emitting options for electrical power and liquid transportation fuels are increasingly considered key components of an energy system with lower overall environmental impacts. Renewable energy technologies (RETs) as well as biofuels technologies have been accelerating rapidly during the past decades, both in technology performance and cost-competitiveness — and they are increasingly gaining market share. These technology options offer many positive attributes, but also have unique cost/benefit trade-offs, such as land-use competition for bioresources and variability for wind and solar electric generation technologies. This paper presents a brief summary of status, recent progress, some technological highlights for RETs and biofuels, and an analysis of critical issues that must be addressed for RETs to meet a greater share of the global energy requirements and lower GHG emissions.
Renewable energy technologies (RETs) – often defined to include wind, solar, geothermal, ocean thermal and kinetic, hydrokinetic, biomass and hydropower (up to about 100 MW-excluding large dams) – are the subject of considerable analysis and evaluation. Recognized as a critical element of a low GHG energy economy (see, for example, Caldeira et al., 2003), RETs are well known for a large, but geospatially specific resource base; historically high costs compared to fossil fuel technology options; rapid market expansion; and resource variability. The academic literature has addressed many of these aspects; for example, (Verbruggen et al., 2010) have recently published a summary of costs, potentials, and barriers in which they present a concrete framework to help clarify multiple and often conflicting definitions of “potential.” All estimates of RET potential rely on fundamental physical resource information, which is thus the critical starting point for any assessment. Martinot et al. (2007) published a comprehensive assessment of the market and policy status of RETs; and many articles have addressed policy issues (for example, see (Fischer and Newell, 2008 and NEF, 2008b), life cycle assessment, or GHG impacts (for example, see (National Research Council (NRC), 2010, Crutzen et al., 2007 and Koshel and McAllister, 2010), or even possible direct climate impacts (Keith et al., 2004 and Wang and Prinn, 2010) related to increased use of RETs within the context of climate change and other policy objectives. This paper – while brief and, therefore, not fully comprehensive – synthesizes the current status of RET markets and economics, presents some example concepts to exemplify ongoing technology innovation, and then discusses the critical issues that are required for RETs to meet a greater share of the global energy requirements and contribute toward mitigating future climate change.
GHG emissions associated with energy extraction and use are a major component of any strategy addressing climate change mitigation. Renewable energy technologies (RETs) as well as biofuels technologies have been accelerating rapidly during the past decades, both in technology performance and cost-competitiveness — and they are increasingly gaining market share. These technology options offer many positive attributes, but also have unique cost/benefit trade-offs, such as land-use competition for bioresources and variability for wind and solar electric generation technologies. Given the growing interest and use in RETs as a viable short- and long-term option for limiting future climate change, key issues that need to be addressed for increased use of RETs include:
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Continued innovation. For most RETS, costs remain high compared to fossil fuel alternatives. Many RETs are relatively immature technically and are, thus, poised for further (and perhaps significant) cost and performance improvements. Further, technologies such as storage systems and dynamic load management warrant further research. Technology innovation should be complemented by advances in system-level integration, geospatially and temporally high resolution resource data, forecasting, systems management, planning, and analytic methodologies.
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Policy frameworks. To integrate RETs into the energy system, it is key to include portfolio approaches that address key issues such as comprehensive and comparable cost/benefit of all energy options, provision of stable and predictable policy environments, and transitional pathways as broader climate related (and CO2-price related) legislation and agreements are developed.
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Improved analysis capabilities. Evaluating RETs in energy systems is especially important as transport electrification accelerates. This ranges from power/energy system models to integrated assessment models.
Clearly, further research and analysis is needed to improve our understanding of the potential of renewable energy technologies with a more diverse energy economy. Even under a scenario with tenfold or more increase in RETs in the short to medium term, from mitigating future climate change perspective, RETs must be viewed as part of broader portfolio of technologies and actions – decarbonization of energy broadly – including CCS, nuclear, agriculture/land management, and natural resource use. To achieve this, exploration of new paradigms and improved representation of renewables in the modeling tools that we use to gain insights about possible future scenarios and their GHG emissions will help elucidate the potential role that renewables and other low-carbon technologies can play in limiting GHG emissions.
