Portfolio Manager has many different GHG emissions metrics. Total GHG Emissions is the sum of Direct GHG Emissions and Indirect GHG Emissions:
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Total GHG Emissions = Direct + Indirect GHG Emissions
- Direct GHG Emissions are associated with onsite fuel combustion (e.g. combustion of natural gas or fuel oil).
- Indirect GHG Emissions are associated with purchases of electricity, district steam, district hot water, or district chilled water. These emissions occur at your utility’s plant not at your property, but they are a result of your property’s energy consumption and therefore contribute to your overall GHG footprint.
However, there are two different methods to calculate Indirect GHG Emissions*:
- Location-Based GHG Emissions are calculated using a regional grid average emissions factor for electricity and national factors for district fuels. Onsite Green Power has zero emissions, but Offsite Green Power is treated as regular grid electricity, meaning you do not get any emissions benefit for Offsite Green Power in this method.
- Market-Based GHG Emissions calculate both Onsite and Offsite Green Power as zero emissions. You can also optionally enter a custom emissions factor for the energy that you purchase (the factor is often documented in a contract with the energy provider) which will be used rather than the grid average factors.
This means there are multiple emissions metrics, including two different “Total” GHG Emissions possibilities:
- Direct GHG Emissions – this is the same for Location-Based and Market-Based.
- Direct GHG Emissions Intensity
- Indirect (Location-Based) GHG Emissions
- Indirect (Location-Based) GHG Emissions Intensity
- Indirect (Market-Based) GHG Emissions (coming in 2025)
- Indirect (Market-Based GHG Emissions Intensity (coming in 2025)
- Total (Location-Based) GHG Emissions = Direct GHG Emissions + Indirect (Location-Based) GHG Emissions
- Total (Location-Based) GHG Emissions Intensity
- Total (Market-Based) GHG Emissions = Direct GHG Emissions + Indirect (Market-Based) GHG Emissions (coming in 2025)
- Total (Market-Based) GHG Emissions Intensity (coming in 2025)
These additional emissions metrics are only relevant to the location-based method:
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Avoided Emissions - Avoided Emissions are the emissions benefits associated with green power use. They are only relevant in terms of location-based emissions, and are not a required part of a GHG inventory. The calculation of total Avoided Emissions includes both Onsite and Offsite Green Power.
- Onsite Avoided Emissions occur when you have an onsite renewable electric system (onsite solar panels or onsite wind turbine) and you retain the rights to the Renewable Energy Certificates (RECs).
- Offsite Avoided Emissions occur when you purchase renewable electricity from your utility or an independent supplier and you own the claims to the RECs. They can also occur in the case of REC arbitrage, a transaction where you sell the RECs associated with your own onsite system and purchase other substitute RECs. In this case, the avoided emissions associated with your green power originate from offsite sources, not your onsite system.
- Biomass GHG Emissions are emissions associated with biogenic fuels such as wood or biogas (captured methane). The only biomass fuel currently available in Portfolio Manager is wood. Biogenic fuels are combusted onsite, but do not contribute to Direct or Total Emissions.
*The methodology for calculating GHG emissions in Portfolio Manager is based on the Greenhouse Gas Protocol Corporate Accounting and Reporting Standard developed by the World Resources Institute (WRI) and World Business Council for Sustainable Development. As the global standard, it serves as the basis for the accounting, inventory and reporting guidance provided by the Environmental Protection Agency’s (EPA) Center for Corporate Climate Leadership, as well as state and non-governmental organization registry, reporting, and recognition programs. This is their Scope 1 and Scope 2 Inventory guidance.