multiple stakeholder groups and whether it underwent peer review. The panel also considered the degree to which each scenario assessed not simply deployment rates and cumulative levels of generation but also economic, financial, human, and environmental facets. Many of the scenarios described here have been released over the past few years, which helps ensure that inputs to the scenarios reflect recent conditions.
Scenarios provide conceptual and quantitative frameworks to describe and assess how renewable resources’ contribution to electricity supply might be significantly increased. Such scenarios are a primary way to quantify materials and manufacturing requirements, human and financial resource needs, and environmental impacts that come with greatly expanding electricity generation from renewable electricity sources. These scenarios typically use qualitative analysis, quantitative assumptions, and computational models of the energy, economic, and/or electricity systems. They attempt to integrate the environmental, technologic, economic, and deployment-related elements into an internally consistent analytical framework. The panel considered two types of scenarios. The first type analyzes increased market penetration of a single resource, such as solar or wind. A prominent example is the 20 percent wind study (DOE, 2008) described in more detail in the following section. Examples for solar energy include the Solar America Initiative (DOE, 2007b), the U.S. Photovoltaic Industry Roadmap (SEIA, 2001, 2004), and the 10 percent solar study (Pernick and Wilder, 2008). The scenarios described here are used to assess issues such as:
Land-use impacts, manufacturing and employment requirements, and economic costs associated with an assumed market penetration of a single renewable resource (e.g., 20 percent electricity generation from wind power or more than 50 percent electricity generation from solar);
The additional transmission, distribution, and other technologies needed to incorporate or enhance the use of intermittent renewable resources in the electricity market; and
The cost-reduction trajectories needed to make solar electricity widely competitive with other electricity sources.