Some local governments purchase cooling, such as chilled water, for either cooling or refrigeration when they do not operate cooling compressors on-site at their facilities. The compressor system that produces the cooling is driven by either electricity or fossil fuel combustion.
Therefore, if a local government purchases district cooling, they will need to quantify the Scope 2 emissions associated with its share of the total cooling demand from the cooling plant. This will allow the local government to estimate the portion of energy used directly attributable to its cooling by utilizing the ratio of cooling demand to energy input for the cooling plant, known as the “coefficient of performance” (CPO).
The LGOP provides a single recommended guideline for this quantification:
- Determine your annual cooling demand (in million BTU or MMBtu).
- Estimate COP for the plant’s cooling system if the COP for the plant is unknown. (If known, proceed to Step 3.) First, identify the type of chiller used by the plant in order to estimate the COP using Table 6.1.
- Determine energy input using Equation 6.26.
- Calculate total cooling emissions using Equation 6.27.
- Calculate GHG emissions resulting from cooling, convert to units of CO2e, and determine total emissions using Equation 6.28.