EPA’s environmental performance

Scope 2 GHG emissions


Purchased electricity

High-temperature hot water (HTHW)

Purchased electricity

Activity data Electricity consumption amounts stated on supplier invoices – expressed in kilowatt hours (kWh)
Calculation method

formula for purchased electricity

Y is Q times EF divided by 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 Emissions associated with purchases of GreenPower are zero
Reference

National Greenhouse Accounts (NGA) Factors conversion factors – Table 5

Department of Environment and Energy

 

High-temperature hot water (HTHW)
Activity data

Natural gas consumption amounts supplied to the thermal cogeneration plant as provided by the plant operator – expressed in gigajoules (GJ).

HTHW consumed at EPA facility – expressed in gigajoules (GJ)

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:

formula for hot water

Y is Q times EC times EF divided by 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)

EC is the energy content factor for natural gas (GJ/kL)

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

formula for hot water CES

Q is P times (Nlt times Phthw plus Nlt times Ploss times 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

formula for proportion of hot water at CES

P is PCES divided by (Nlt times Phthw)

Where –

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

Assumptions

The following were based on an energy audit of the cogeneration plant conducted by Sinclair Knight Merz (SKM):

  • proportion of energy content of natural gas dedicated to HTHW generation based on energy audit: 35%
  • proportion of energy content of natural gas that is lost in the system based on energy audit: 35%
  • proportion of energy content of natural gas dedicated to auxiliary services based on energy audit: 1%
Reference SKM (Sinclair Knight Merz), 2003.  La Trobe University Cogeneration Plant Energy Audit, LTU Level 2, Final, October 2003

Page last updated on 24 Aug 2017