The transportation sector accounts for a large and growing share of global greenhouse gas (GHG) emissions. Worldwide, motor vehicles emit well over 900 million metric tons of carbon dioxide (CO2) each year, accounting for more than 15 percent of global fossil fuel-derived CO2 emissions. In the industrialized world alone, 20-25 percent of GHG emissions come from the transportation sector. The share of transport-related emissions is growing rapidly due to the continued increase in transportation activity. In 1950, there were only 70 million cars, trucks, and buses on the world's roads. By 1994, there were about nine times that number, or 630 million vehicles. Since the early 1970s, the global fleet has been growing at a rate of 16 million vehicles per year. This expansion has been accompanied by a similar growth in fuel consumption. If this kind of linear growth continues, by the year 2025 there will be well over one billion vehicles on the world's roads. In a response to the significant growth in transportation-related GHG emissions, governments and policy makers worldwide are considering methods to reverse this trend. However, due to the particular make-up of the transportation sector, regulating and reducing emissions from this sector poses a significant challenge. Unlike stationary fuel combustion, transportation-related emissions come from dispersed sources. Only a few point-source emitters, such as oil/natural gas wells, refineries, or compressor stations, contribute to emissions from the transportation sector. The majority of transport-related emissions come from the millions of vehicles traveling the world's roads. As a result, successful GHG mitigation policies must find ways to target all of these small, non-point source emitters, either through regulatory means or through various incentive programs. To increase their effectiveness, policies to control emissions from the transportation sector often utilize indirect means to reduce emissions, such as requiring specific technology improvements or an increase in fuel efficiency. Site-specific project activities can also be undertaken to help decrease GHG emissions, although the use of such measures is less common. Sample activities include switching to less GHG-intensive vehicle options, such as electric vehicles (EVs) or hybrid electric vehicles (HEVs). As emissions from transportation activities continue to rise, it will be necessary to promote both types of abatement activities in order to reverse the current emissions path. This Resource Guide focuses on site- and project-specific transportation activities. This National Energy Technology Laboratory (NETL) publication, "Battery-Powered Electric and Hybrid Electric Vehicles to Reduce Greenhouse Gas (GHG) Emissions: A Resource Guide for Project Development" provides national and international project developers with a guide on how to estimate and document the GHG emission reduction benefits and/or penalties of battery-powered and hybrid-electric vehicle projects. This primer also provides a resource for the creation of GHG emission reduction projects for the Activities Implemented Jointly (AIJ) Pilot Phase and in anticipation of other market-based project mechanisms proposed under the United Nations Framework Convention on Climate Change (UNFCCC). Though it will be necessary for project developers and other entities to evaluate the emission benefits of each project on a case-by-case basis, this primer will provide a guide for determining which data and information to include during the process of developing the project proposal.