The benchmark goal that drives the report is to achieve a 20 percent reduction in carbon dioxide (CO2) emissions in Colorado's electricity sector below 2005 levels by 2020. We refer to this as the '20 x 20 goal.' In discussing how to meet this goal, the report concentrates particularly on the role of utility-scale renewable energy and high-voltage transmission. An underlying recognition is that any proposed actions must not interfere with electric system reliability and should minimize financial impacts on customers and utilities. The report also describes the goals of Colorado's New Energy Economy5 - identified here, in summary, as the integration of energy, environment, and economic policies that leads to an increased quality of life in Colorado. We recognize that a wide array of options are under constant consideration by professionals in the electric industry, and the regulatory community. Many options are under discussion on this topic, and the costs and benefits of the options are inherently difficult to quantify. Accordingly, this report should not be viewed as a blueprint with specific recommendations for the timing, siting, and sizing of generating plants and high-voltage transmission lines. We convened the project with the goal of supplying information inputs for consideration by the state's electric utilities, legislators, regulators, and others as we work creatively to shape our electricity sector in a carbon-constrained world. The report addresses various issues that were raised in the Connecting Colorado's Renewable Resources to the Markets report, also known as the SB07-91 Report. That report was produced by the Senate Bill 2007-91 Renewable Resource Generation Development Areas Task Force and presented to the Colorado General Assembly in 2007. The SB07-91 Report provided the Governor, the General Assembly, and the people of Colorado with an assessment of the capability of Colorado's utility-scale renewable resources to contribute electric power in the state from 10 Colorado generation development areas (GDAs) that have the capacity for more than 96,000 megawatts (MW) of wind generation and 26,000 MW of solar generation. The SB07-91 Report recognized that only a small fraction of these large capacity opportunities are destined to be developed. As a rough comparison, 13,964 MW of installed nameplate capacity was available in Colorado in 2008. The legislature did not direct the SB07-91 task force to examine several issues that are addressed in the REDI report. These issues include topics such as transmission, regulation, wildlife, land use, permitting, electricity demand, and the roles that different combinations of supply-side resources, demand-side resources, and transmission can play to meet a CO2 emissions reduction goal. This report, which expands upon research from a wide array of sources, serves as a sequel to the SB07-91 Report. Reports and research on renewable energy and transmission abound. This report builds on the work of many, including professionals who have dedicated their careers to these topics. A bibliography of information resources is provided, along with many citations to the work of others. The REDI Project was designed to present baseline information regarding the current status of Colorado's generation and transmission infrastructure. The report discusses proposals to expand the infrastructure, and identifies opportunities to make further improvements in the state's regulatory and policy environment. The report offers a variety of options for consideration as Colorado seeks pathways to meet the 20 x 20 goal. The primary goal of the report is to foster broader discussion regarding how the 20 x 20 goal interacts with electric resource portfolio choices, particularly the expansion of utility-scale renewable energy and the high-voltage transmission infrastructure. The report also is intended to serve as a resource when identifying opportunities stemming from the American Recovery and Reinvestment Act of 2009.