Reportwise methodology


The Emitwise Reportwise tool calculates company level GHG emissions in line with the GHG Protocol for scope 1 and 2 emissions. No responsibility is taken for figures entered by the user, and no verification of data is provided.

Greenhouse Gases (GHGs), or gases related to global climate change, are required by UK Government to be reported by quoted and large unquoted companies plus Limited Liability Partnerships (LLPs) according to the Companies (Directors’ Report) and Limited Liability Partnerships (Energy and Carbon Report) Regulations 2018 (“the 2018 Regulations”). In particular, this regulation implements the Streamlined Energy and Carbon Reporting (SECR) policy, which came into force on 1st April 2019, requiring inclusion for all relevant companies from April 2020. This requires reporting on energy use, as well as scope 1 and 2 GHG emissions.

Scope 1 refers to the emissions associated with combustion of fuel directly onsite or within company vehicles as well as direct emissions released during production or processing by an organisation. Scope 2 includes all emissions associated with purchased electricity, heat and steam. These are considered linked to the operational emissions, but indirectly as the emissions are generated at the point of combustion, not at the point of use at the company facilities. Reportwise can be used to report SECR requirement GHG emissions and energy consumption or simply voluntary reporting of a company’s scope 1 and 2 as preferred.

The tool calculates scope 1 emissions using company provided aggregated fuel use onsite, vehicle fuel consumption/vehicle use and refrigerant replacement as a proxy for refrigerant emissions to the environment. Other fugitive emissions and process emissions are added directly by the user and multiplied according to global warming potential GWP. Where preferred data (typically physical fuel consumption data) is unavailable, a data hierarchy is in place to select the next best available data to make the calculations for each section. In particular, in company vehicle emission calculations, companies are encouraged to calculate emissions based on individual emissions factors per vehicle if available, and where these are not available, distance and vehicle type are used. If no physical data is available, spend data is used and pricing estimated based on BEIS 2019 UK fuel pricing data, and Defra emission factors applied to estimated volume of fuel consumed.

Air and water-based vehicle travel is difficult to calculate at generic level, and therefore this is not recommended as good practice, but as a starting point for year 1 reporting only. Emission factors are based on industry data but are noted to be representative only as there is significant variation in emissions of planes, ships and boats etc due to size, speed travelled, sea or flight conditions, distance travelled (for flights – as more fuel is consumed during take off than during cruising for example). Where industry emission factors were not available, such as for passenger ships, publicly disclosed intensity emission factors for the major corporate operators was used (covering over 78% of market share according to Griffith University).

Scope 2 emissions are calculated based on country level emission factors applied to purchase of electricity by source, plus purchased heat by source. Emissions are calculated according to market-based methodology, though location-based emissions are also calculated and companies can contact Emitwise for more detail
of this if required.

GHG emissions associated with combined heat and power CHP and district heating and cooling are calculated based on CHP average efficiencies alongside Defra emission factors for fuel types, plus average emissions of known CHP plants in the UK. Total energy use is given in MWh and includes onsite energy use only – this includes all purchased and generated electricity consumption, stationary fuel use and purchased or generated heat and steam (adjusting for double count if relevant).

The GWPs used n the calculation of CO2e are based on the Intergovernmental Panel on Climate Change IPCC Fourth Assessment Report AR4 over a 100-year period.

The tool utilizes numerous sources of data, and these are applied based on relevancy to the input data provided by the company. A comprehensive list of data sources within the tool is provided below, though many of these may not be relevant for the specific report.

Sources of data

AIB (2017) European Residual Mix. Available from: [Accessed 30/01/2020]

Australian Government Department of the Environment and Energy (2018) National Greenhouse Accounts Factors. Available from: [Accessed 30/01/2020]

BEIS (2019) Prices of fuels purchased by non-domestic consumers in the UK. Available from: [Accessed 30/01/2020]

BEIS (2020) Monthly and annual prices of road fuels and petroleum products. Available from: [Accessed 03/02/2020]

Carbon Footprint Ltd (2019) Country specific electricity greenhouse gas emission factors. Available from [Accessed 30/01/2020]

Carnival Corporation & Plc (2018) Energy and Emissions. Available from: [Accessed 10/02/2020]

DECC (2008) CHP – Environmental. Available from: [Accessed 05/02/2020]

Defra (2019) UK Government GHG Conversion Factors for Company Reporting

Institute for Global Environmental Strategies (2019) List of Grid Emission Factors, version 10.7. Available from:

Griffith University (2018) Cruise ship emissions. Available from: [Accessed 30/01/2020]

IPCC (1997) Revised 1996 IPCC Guidelines for National Greenhouse Gas Inventories Reference Manual. Available from: [Accessed 17/01/2020]

IPCC (2003) Good Practice Guidance and Uncertainty Management in National Greenhouse Gas Inventories: Aircraft. Available from: [Accessed 10/02/2020]

IPCC (2018) IPCC Emissions Factor Database

New Zealand Ministry for the Environment (2019) Measuring, reporting and offsetting greenhouse gas emissions

Royal Caribbean (2019) Seastainability 2018. Available from: [Accessed 10/02/2020]

UNFCC (2019) National Inventory Submissions 2019. Available from: [Accessed 04/02/2020]

US EPA (2019) Emissions and Generation Resource Integrated Database (eGRID). Available from: [Accessed 30/01/2020]