The Climate Trust has developed marginal grid intensity factors for U.S.-based projects that displace grid electricity to assist in calculating such a project’s carbon dioxide offsets. The Trust has also compiled a list of resources for electricity sector baselines outside of the U.S.
U.S. Electricity Grid Intensity Factors
For projects submitted for The Climate Trust’s 2005 RFP, the Trust requests project developers use the following grid intensity factors for U.S.-based projects. Use these factors when calculating a U.S.-based project’s carbon dioxide offsets. These guidelines apply for both projects that supply electricity to the grid (renewable generation, cogeneration, power plant upgrades, etc.) as well as projects that reduce demand for electricity (energy efficiency). For a map of the U.S. grid subregions, click here.
This map is of the NERC (National Energy Reliability Council) subregions. Regions are also referenced by their eGrid subregion name, show in parenthesis in the chart above. This map is courtesy of eGrid.
If you are unsure of the subregion for your project, please utilize the EPA’s Power Profiler and follow these directions:
Enter the Power Profiler.
Enter the zip code of your project.
Select the electric utility (it does not matter which one), click “Next.”
Click on the link to “your region of the power grid.”
Find the emissions factor for that region in the chart above.
Electricity Sector Baseline Guidance for non U.S.-based Projects
The Climate Trust does not yet have standard electricity sector baselines for non U.S.-based projects. The Climate Trust requests that proposed baselines incorporate the latest carbon offset project standards and procedures.
CDM: Although only a few electricity sector baseline methodologies have been approved by the CDM, their Website contains information on proposed projects and project methodologies that can serve as a resource for project applicants.
PCF: The World Bank’s Prototype Carbon Fund (PCF) makes available most of the project development documents – including baseline studies – for it’s portfolio of offset projects. Non-U.S. electricity sector baseline data can be found on their website.
Methodology for Combined Margin Grid Intensity Factors for U.S. Based Projects
The Climate Trust’s marginal grid intensity factors are derived from two, evenly weighted factors: 50% marginal grid intensity and 50% marginal build (the power facility displaced by the offset project).
This combined margin factor was selected for the following reasons:
It is an appropriate compromise between the two arguments that offset projects displace the marginal power on the grid and that offset projects displace the marginal build.
A combined margin factor is one of the quanitification Methodologies approved by the CDM Executive Board.
It is one of the methodologies under assessment by the GHG Protocol's Grid Connected Electricity Sector Workgroup.
Marginal grid intensity: The Climate Trust calculated the marginal grid intensity factors using a weighted average of the emissions rates of the fossil fuel plants for the specific region. The Climate Trust determined that U.S. EPA’s eGrid has the most useful regional data on emission rates. One of the preferred methods to determine marginal power sources is to use data on the power plant rate order (the order in which the power facilities are utilized to meet demand). As eGrid does not contain such data, the weighted average of the fossil emissions rates was used as a proxy.
Marginal build: For the marginal build factor, The Climate Trust assumed that the most likely next build will be natural gas with an emissions factor of 0.81 pounds/kWh. We applied this assumption to all regions. The U.S. Energy Information Agency's Annual Energy Outlook 2005 provided the best available information on regional projections of power capacity additions. The report states that the majority of new generation from 2005-2015 will be natural gas. Although a combination coal/natural gas emissions factor could be used for several regions, The Climate Trust determined that a natural gas factor is a more conservative assumption from an offset quantification standpoint.
