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GHG Accounting

Greenhouse gases (GHGs) are chemical compounds, which allow direct sunlight (energy) to reach the Earth’s surface.  Some of the energy is reflected back from the surface into the atmosphere.  GHGs “trap” this energy and hold the energy (heat) in the atmosphere.  Please visit Second Nature’s reporting platform for UMBC’s GHG Report Summaries.

Common Sources of Emissions by Scope

GHG Inventory Development

All emissions sources at UMBC are annually inventoried and tracked.  The emissions for each scope are calculated by multiplying the consumption of the fuel by an Emission Factor (EF) to calculate the mass of each GHG in that fuel source.  Those values are multiplied by the associated Global Warming Potential (GWP) to convert all the emissions to a standard unit of measure known as carbon dioxide equivalent (eCO2).  All emissions are reported as metric tons of eCO2 (MTeCO2).  UMBC conducts our inventory utilizing the Clean Air Cool Planet Campus Carbon Calculator.

GHG Scopes

Scope 1: Direct Emissions produced from sources on campus, which UMBC has direct control over.

  • Includes the combustion of fuels (e.g. natural gas, fuel oil, etc) and the management of refrigerants.

Scope 2: Indirect Emissions produced from the consumption of purchased electricity.

  • Includes emissions associated with the generation of electricity.

Scope 3: Other Indirect Emissions produced from activities associated with UMBC but directly owned or controlled by UMBC.

  • Includes commuter emissions, UMBC sponsored air travel, landfilling of municipal solid waste.

Renewable Energy Certificates (RECs)

A renewable energy certificate, or REC, is a market-based instrument that represents the property rights to the environmental, social and other non-power attributes of renewable electricity generation. RECs are issued when one megawatt-hour (MWh) of electricity is generated and delivered to the electricity grid from a renewable energy resource. Because the physical electricity we receive through the utility grid says nothing of its origin or how it was generated, RECs play an important role in accounting, tracking, and assigning ownership to renewable electricity generation and use. On a shared grid, whether from on-site or off-site resources, RECs are the instrument that electricity consumers must use to substantiate renewable electricity use claims.

Both offsets and RECs represent the environmental benefits of certain actions that can help mitigate GHG emissions. Offsets represent a metric ton of emissions avoided or reduced; RECs represent attributes of 1 MWh renewable electricity generation. Offsets and RECs, however, are fundamentally different instruments with different impacts, representing different criteria for qualification and crediting in the context of inventory or emissions footprint. For additional information, please see the US EPA’s Offsets and RECs: What’s the Difference? guidance document.