Methodology

It compares a business-as-usual product (Option 0) against Australian recycled-content alternatives (Options 1 and 2) on two independent measures:

• Whole-of-life cost, expressed as an Equivalent Annual Cost (EAC).
• Recycled soft plastic diverted, in tonnes, and the associated greenhouse benefit.

The two are kept separate on purpose: the cost calculation needs no emissions data, and the material tonnage needs no modelling. A gap in one never affects the other.

Equivalent Annual Cost is the standard way to compare assets with unequal service lives— it converts a whole-of-life cost into a cost per year of service, so a product that lasts 25 years is compared fairly against one that lasts 8. Lower EAC is better.

For each option, over its own service life n at real discount rate r:

annuity factor  A = (1 − (1 + r)^−n) / r      (= n when r = 0)
whole-of-life NPV  V = (upfront × qty) + PV(maintenance) − PV(residual)
EAC = V / A

The scope of the EAC is stated with every result. If you leave maintenance and residual blank it is “Capital only” — a complete calculation of a narrower question, and a conservative one, because recycled products generally need less maintenance than the timber, steel or concrete they replace. Where service life is the uncertain input, the break-even service life tells you how long an option must last to match the baseline on capital alone — a threshold to judge against warranty and stated design life, rather than a number you must know.

When a service life has not been provided — most listings give one, but not all — the calculator does not assume a figure. Instead it falls back to the break-even service life: because that figure solves for the life at which an option matches the baseline, it can be shown without knowing the life in advance. So the comparison is never blank; the question simply becomes “will it last that long?” against the supplier’s warranty and design life. Where a supplier states a range (say “25 to 50 years”), the field is seeded with the lower figure and flagged, for you to confirm or adjust.

The calculator produces the same numbers as the companion spreadsheet, cell for cell — it writes your inputs into that workbook and leaves its formulas untouched, so the two cannot drift.

The headline material figure needs no modelling and no counterfactual:

recycled soft plastic (t) = unit mass (kg) × recycled content % × soft-plastics share % × qty ÷ 1000

The greenhouse benefit is that tonnage multiplied by a net emissions factor, and is shown as a range — never a single number. The least-favourable end pairs the smallest avoided-production benefit with the highest process burden; the most-favourable end does the opposite. Negative is a benefit.

Diverting plastic from landfill saves landfill volume, not methane — plastic contains no degradable organic carbon. The emissions benefit comes from displacing virgin polymer production.

The factors are held in a versioned register, not written into the software. The active set:

Units: t CO2-e per tonne recyclate. All figures are 100-year global warming potential (IPCC AR5), consistent with the National Greenhouse Accounts Factors and Paris Agreement reporting. Only the central values are published by the source; the low and high on A1–A3 are sensitivity bounds set by Tidal Circular, and are marked as such.

The components A1–A3 sum to a net of -1.54; the source publishes the net (A4) as −1.53. The small difference is rounding in the published components, not an error — the calculator uses the sum of A1–A3.

Source: Environmental benefits of recycling, Appendix 6 — Plastics, Table 19 (mixed plastics, kerbside source) · NSW EPA (study published by DECCW NSW) 2010. This is the dataset behind the EPA’s Recyculator tool.

The greenhouse factors (A1–A4) come from Appendix 6 — Plastics, Table 19 of the NSW EPA study, for the “mixed plastics” category. That category is defined as plastics outside the study’s specific categories or in a form that doesn’t allow segregated recycling — it explicitly names laminate films, which is our material — and models the avoided product as virgin polypropylene, a typical substitute.

Because that factor is already an average across a heterogeneous stream, and the study’s only categories are PET, HDPE, PVC, mixed plastics and tyres, there is no LDPE-specific factor to apply a polymer split to. Asking suppliers for polymer percentages and multiplying through would add false precision, not accuracy — so we don’t collect them.

A separate NSW appendix (Appendix 7) covers collection, sorting and energy assumptions. It complements Appendix 6 — different boundaries of the same study, not a competing source.

• The source model assumes offshore reprocessing (~20,000 km round trip to China). Australia has since banned that export and NSW has domestic reprocessing capacity, so this is a CONSERVATIVE FLOOR for domestically processed material.
• The avoided product is modelled as virgin polypropylene. The factor does not transfer where the counterfactual is a non-polymer material (timber, steel, concrete).
• The dataset uses a 2001–02 electricity mix. The recycling process burden is electricity-intensive and the grid has since decarbonised, so A2 is likely overstated today.

The platform reports what suppliers declare, with their verification status shown — it does not assert claims on their behalf, and it does not independently verify supplier data. Where a figure rests on a general published factor rather than product-specific, scheme-verified data, it is labelled indicative. An interested council should review the supplier’s own evidence before relying on any figure.