Purpose
Trellis has been working on adjustments to the Trellis platform's approach to GreenPower calculations to better align with the approach employed under the Climate Active assessment framework.
Specifically this relates to the se of the Market-based emissions factor when acquitting emissions related to purchased GreenPower and other renewable electricity inputs (such as purchased power agreements, behind the meter consumption, ACT electricity and others).
Documentation
The default location-based emissions factors cannot be used when offsetting emissions associated with renewable electricity. Rather, the alternative market-based factor must be used, with the electricity usage to which emissions are tenable modified by the quantity of renewable electricity, otherwise denoted as the “residual” electricity.
GreenPower emission factors are therefore set to zero across all scopes.
There is no need for changes to the underlying client data as application is achieved via a toggle on a report.
Note that if the GreenPower is 100% then there is virtually no impact on emissions (although see below). However, there will be changes in emissions estimates related to GreenPower at less than 100% (generally 20% or 50%).
Residual electricity is calculated via a mildly convoluted approach that requires knowledge of the pertinent Residual Power Percentage (RPP) which is used to calculate the Mandatory LRET (see RET below) portion of the electricity usage.
The RPP is updated annually but currently in the order of 18.75%.
For a worked example and comparison:
Given: Assume a South Australian facility has total annual electricity consumption (E):
,
and a GreenPower percentage (G) of 50%:
.
Residual Electricity: We calculate Residual Electricity (R) as follows:
Market-Based Emissions: The Scope 2 (market-based) emissions are therefore:
Location-Based Emissions: The Scope 2 (location-based) uses total electricity (E):
Note Climate Active requires reporting of both market and location-based electricity emissions.
Note also that Climate Active has a binary approach to the overall emissions assessment in that reporting must select one of the above for ALL electricity consumed.
Finally it can be seen that when GreenPower is at 100% the residual electricity and related emissions are actually negative, but are reported as Zero (emissions related to renewable electricity can only go to zero rather than contribute to other sources).
Market-based electricity reporting will be implemented via a toggle that adjusts both the input electricity usage (by calculating the "residual" non-renewable electricity) and emissions factor from the location based (default) factor to the market based factor (which operates nationally).
What is the RET
The Renewable Energy Target (RET) is government scheme administered by the Clean Energy Regulator that aims to reduce emissions from the electricity sector. The scheme was initiated in 2020 and will run until 2030.
See https://cer.gov.au/schemes/renewable-energy-target, Accessed Jan 2025 for more information.