How does Trace calculate waste emissions?

Overview

• Waste treatment at facilities owned or controlled by the reporting company is accounted for in scope 1 and scope 2. 

• This page explains our methodology for waste treatment in facilities owned or operated by third parties, which sit in Scope 3 Category 5 under the GHG Protocol.

• Emissions are driven by both the amount of waste generated and how it is treated, for example landfill, recycling, composting.

• Trace supports multiple calculation methods to reflect the reality that waste data maturity varies widely across organisations.

• A combination of approaches can be used depending what data is available.

Calculation options compared

Despite being the least accurate, option 3 is still the most commonly used approach by companies in their first year of carbon measurement.

Emissions factors

• Trace applies local waste emissions factors from the Australian Governance (NGA factors) and UK Government (DEFRA) and other local sources as required. If a local emissions factor is not provided, the Australian factor is applied by default.

• The factors represent an estimate of lifetime emissions from waste degradation in a landfill. In reality, waste disposed in a landfill will degrade and emit over a period of decades. The factors do not consider any landfill gas capture occurring at the landfill. 

• Where the reporting company reports in litres not kg of waste, Trace uses the Australian Government's Volume to mass conversion factor
  (t/m3) by waste type (Table 15 and 16), where 1 m3 = 1000 litres.

Data collection options to improve accuracy                          

There are a variety of different methods to work out the amount of waste your organisation generates. Waste transfer/consignment notes from your commercial waste collector are a good place to start as it may have specific information on the waste that has been collected from you. Alternatively, the commercial waste collector may be able to advise on an average weight you can apply given the waste infrastructure you have on site.

or you can conduct a waste audit - this is where a member of staff samples the composition of your waste and weighs the waste and/or recycling generated on a regular basis.                                    

To move from estimated or spend based methods to measured data, Trace recommends:

• Physical waste audits

  • Conduct a representative week audit to measure actual waste by type this is where a member of staff samples the composition of your waste and weighs the waste and/or recycling generated on a regular basis.

  • Use this as a baseline and extrapolate annually.

  • Download WRAP's waste audit tool here.

• Landlord or facility records

  • In leased buildings, request building wide waste volumes from landlords.

  • Allocate waste based on your share of floor area if tenant level data is not available.

• Data from your waste collector 
  • The commercial waste collector may be able to advise on an average weight you can apply given the waste infrastructure you have on site.

Deep Dive Into Approach 3: Estimating waste generation 

• Trace recommends estimating waste generated where the reporting company does not collect data on waste generated. 

• Waste volumes can be estimated using third party benchmarks according to floor area (m²) or FTE, for example:

  • CalRecycle data here for average waste per m2 produced by premise type.
  • Business Waste UK for average per FTE in an office (preferred approach for office waste)

• Note: Most benchmark datasets are at least 10 years old and likely to be conservative given the shift to digital work in that time.

• Factors Affecting Office Waste per m²
  • Occupancy: The amount of waste is closely tied to the number of employees. A common benchmark for office space is 10 m² per person. The average office worker generates about 2 kg of waste per day (500 kg annually).
  • Waste Management: Offices with robust recycling programs produce less general waste. About 70% of office waste is recyclable, but only a fraction of this is actually recycled in many cases.
  • Office Type: The nature of the business can affect waste generation. For example, a law or finance firm might have different waste streams (e.g., more paper, secure shredding) compared to a tech startup.
  • Amenities: Offices with internal catering facilities will produce more food waste than those without.
  • Working Model: Hybrid working models, where fewer employees are in the office daily, can lead to lower overall waste generation per day, although the waste per occupied desk might remain similar. 

Recommended benchmarks for average waste generated by employee in an office

Accounting for emissions from recycling

• Under the GHG Protocol Scope 3 accounting methodology, emissions from recycling processes are reported as 0 or close to zero under Scope 3, Category 5.

• This is because emissions associated with recycling and energy recovery are considered Scope 1 of the re-processor and Scope 3, Category 1 of the company that buys the recycled material.

• Where the emissions attributed to the company which recycles the waste is not 0, this covers only the collection of waste from their site and deposit at the first point of processing.

• Claims of negative or avoided emissions associated with recycling (i.e. claims beyond a reduction in processing emissions and beyond a reduction in waste treatment emissions in categories 5 or 12) are not included in, or deducted from, the scope 3 inventory