Electricity Use

1. Determine annual electricity use from each facility (usually in kWh or MWh). Potential sources for obtaining electricity use activity data include accounts payable, departmental records, utility bills, fuel vendors/suppliers, etc.
2. Select the appropriate emission factors that apply to the electricity used (usually in units of pounds of GHG per kWh or MWh). The two options for recommended electricity emission factors include:
3. Verified utility-specific emission factors (Table G.5)
4. eGRID regional default emission factors by subregion (Figure G.1, Table G.7 and G.8 in Protocol) or California Grid Average Factor (Table G.6 in Protocol)
5. Determine your total annual emissions in metric tons of carbon dioxide equivalent first using Equation 6.8 and then 6.9 to convert to CO₂e.

Electricity use estimation can be quantified based on the local government’s share of the building’s floor space and the building’s total electricity consumption.

1. Collect the following information, which should be available from the building’s property manager:
   a.    Total building area (sq ft)
   b.    Area of entity’s space (sq ft)
   c.    Total building annual electricity use (kWh)
   d.    Building occupancy rate (e.g. if 75% of building is occupied, use 0.75)
2. Using the collecting information, utilize Equation 6.10 to calculate estimated electricity use.
3. Calculate electricity’s CO₂, CH₄, and N₂O emissions by using Equations 6.8 and 6.9 in Recommended Approach section.

Electricity use estimation can be quantified based on energy consumed at the building or facility in another year:

1. Determine annual electricity consumption in proxy year (either another calendar year or else a fiscal year).
2. Normalize for heating and cooling degree days. Heating and cooling degree days can be found at: 
   www7.ncdc.noaa.gov/CDO/CDODivisionalSelect.jsp#

Calculate electricity’s CO₂, CH₄, and N₂O emissions by using Equations 6.8 and 6.9 in Recommended Approach section.

Fuel use can be also be estimated based on the size and function of the building or facility:

1. Determine the size of the facility measured in floor area (square feet)
2. Identify comparable facilities with known annual electricity use and square footage. If electricity consumption for another comparable facility owned or operated by the local government is not available, the U.S. Energy Information Administration’s Commercial Building Energy Consumption Survey can be utilized http://www.eia.doe.gov/emeu/cbecs/
3. Determine electricity used per square foot at comparable facility (e.g. kWh/square foot).
4. Estimate electricity used at facility.
5. Calculate electricity’s CO₂, CH₄, and N₂O emissions by using Equations 6.8 and 6.9 in Recommended Approach section.

When metered electricity use records are not available for streetlights and traffic signals, the alternate methodology for estimating electricity use is based on installed wattage:

1. Determine the number and wattage of all bulbs in the system (available usually from either streets department of the electricity utility)
2. Estimate the average annual daily operating hours for each group of lights.
3. Estimate annual electricity consumption for each group of lights using Equation 6.13.
4. Calculate streetlight electricity’s CO₂, CH₄, and N₂O emissions by using Equations 6.8 and 6.9 in Recommended Approach section.