EPA’s environmental performance

Scope 2 GHG emissions


Scope 2 sources are indirect greenhouse gas emissions associated with purchased energy commodities including electricity and steam.

One this page:

Purchased electricity

Activity data Electricity consumption amounts and green power percentages as stated on supplier invoices or provided directly from property managers - expressed in kilowatt hours (kWh). In the instance that EPA is the sole tenant for a site, electricity data covering both tenant and base building was collected. In the instance EPA is not the sole tenant for a site, base building electricity data was collected separately from tenant data. This is relevant for Carlton, Exhibition St, CES Macleod and South West Geelong sites.
Calculation method

 Y = Q × EF/1000

Where:

Y is the scope 2 emissions measured in t.CO2-e

Q is the quantity of electricity (kWh)

EF is the scope 2 emission factor for Victoria (kg.CO2-e/kWh)

Assumptions

Where data was not available for the final months of 2017-18, estimations were made using daily consumption, calculated using data provided for previous months.

Data was not available for two air monitoring stations (AMS) which were unique solar instruments and powered by 100 per cent solar energy. Estimations were made using the capacity of the solar panels and average daily energy production of solar systems, as guided by the Australian Photovoltaic (PV) Institute. Average daily energy production from photovoltaic cells for Boroondara, Victoria was chosen due to geographical proximity to EPA's instruments.

Data was not available for a number of AMS. Estimations were made based on known consumption of similar AMS.

In the instance EPA is not the sole tenant of the building and data was provided for the entire building or one floor of a building, GHG emissions were apportioned using EPA's net lettable area (NLA) as a portion of the total NLA for the building or floor.

Emissions associated with purchases of green power are zero.

Factors EF: 1.08 (kg.CO2-e/kWh)
 Reference  

Average daily production of solar solar systems : PV Performance by Climate Region (2018), Australian PV Institute

National Greenhouse Accounts (NGA) Factors conversion factors - Department of Environment 

  • Table 5 (Indirect (scope 2) emission facts for consumption of purchased electricity or loss of electricity rom the grid (Victoria).

High-temperature hot water (HTHW)
Activity data Activity data relevant for EPA's CES Macleod site only.

HTHW consumed at CES Macleod as provided by the plant operator - embodied energy expressed in gigajoules (GJ).

Natural gas consumption quantities supplied to the thermal cogeneration plant and hot water boiler as provided by the plant operator - expressed in gigajoules (GJ).

Proportion of energy content of natural gas converted to HTHW and losses and auxiliary services attributable to HTHW generation for cogeneration plant as identified in an energy audit conducted by the plant operator in 2003.

Proportion of energy content of natural gas converted to HTHW and losses and auxiliary services attributable to HTHW generation for hot water boiler as estimated by plant operator.

Calculation method

The preferred methodology is the efficiency method as described by the GHG Protocol guidance - Allocation of GHG Emissions from a Combined Heat and Power (CHP) Plant. Due to inadequate onsite metering, there is a lack of data that meant application of the efficiency method was not possible. The following method was developed in collaboration with the plant operator:

Y = Q × EF/1000

Where:

Y is the scope 2 emissions measured in t.CO2-e

Q is the quantity of HTHW consumed by EPA’s Centre for Environmental Studies (CES) facility (GJ)

EF is the full cycle emission factor natural gas (kg.CO2-e/GJ).

Q = P x [(Nlt x Phthw) + (Nlt x Ploss x Hfrac)]

Where;

P is the proportion of HTHW consumed by EPA’s CES facility (%)

Nlt is the quantity of natural gas consumed by the co-generation plant at La Trobe University.

Phthw is the proportion of natural gas attributed to HTHW generation

Ploss is the proportion of natural gas attributed to system loses and auxiliary services

Hfrac is the fraction of system loses and auxiliary services attributed to HTHW

 P = PCES/Nlt x Phthw

Where –

PCES is the quantity of HTHW consumed by EPA’s CES facility

Assumptions

Where data was not available for the final months of 2017-18, estimations were made using average daily consumption, calculated using data provided for previous months.

As EPA is not the sole tenant of the CES Macleod building, GHG emissions are apportioned using EPA’s NLA as a portion of the total NLA for the building.

On 20 December 2017, La Trobe's cogeneration plant was decommissioned. Since then, La Trobe has provided HTHW to CES Macleod via hot water boilers. Prior to 20 December 2017, La Trobe's hot water boilers supplemented HTHW supply from the cogeneration plant only in the cooler months or when the cogeneration plant was not operating. As such, prior to December 2017, we have assumed all HTHW provided by La Trobe to CES was produced by the cogeneration plant alone. From January onwards, we have assumed all HTHW was produced by the hot water boilers. For the month of December we have assumed 65 per cent was produced by the cogeneration plant and 35 per cent was produced by the hot water boilers based on the date of the switch.

The following are relevant for the cogeneration plant and were based on an energy audit of the cogeneration plant conducted by Sinclair Knight Merz:

  • Proportion of energy content of natural gas converted to HTHW: 35 per cent 
  • Proportion of energy content of natural gas attributable to losses and auxiliary services for HTHW: 2 per cent.

The following are relevant for the hot water boilers and were based on estimates by the plant operator:

  • Proportion of energy content of natural gas converted to HTHW: 85 per cent 
  • Proportion of energy content of natural gas that is lost in the system: 15 per cent 

Proportion of energy content of natural gas attributable to losses and auxiliary services: 100 per cent

Factors EF: 55.43 (kg.CO2-e/GJ)
Reference

National Greenhouse Accounts Factors (July 2017) - Department of Environment and Energy

  • Table 2: Emission factors for the consumption of natural gas (Victoria)
  • Scope 3: Table 38: Scope 3 emission factors – natural gas for a product that is not ethane (inclusive of coal seam gas) (Victoria)

SKM (Sinclair Knight Merz), 2003.  La Trobe University Cogeneration Plant Energy Audit, LTU Level 2, Final, October 2003

Page last updated on 9 Sep 2019