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Sustainable Travel

As the world opens up again, it is clear there is both a need and a desire for in-person, face-to-face interaction. The meetings that matter the most happen in person, and companies will always need their employees to travel in order to come together. That being said, we have a responsibility to enable these meetings while minimising the impact they have on our environment.

Kudos & Thrust Carbon

Kudos Travel Technology understands the importance of quality emissions data for transparency to individuals and companies about their travel choices. That is why we partnered with Thrust Carbon who has a vision of a world where our actions do not have to cost the earth.

Who is Thrust Carbon?

Thrust Carbon is a London-based tech company. They build technology that enables forward-thinking companies to operate sustainably and offer green products and services. By comprehensively calculating carbon emissions, such as for travel, they provide a complete carbon picture and accurate reporting to large companies and SMEs. 

The integration of Thrust Carbon allows our platform’s users to factor sustainability into their travel decisions in an easy and meaningful way. Emission data for not only Air but also Hotel and Car Rental will be provided, including the total CO2e for the trip before and after booking. Companies and individual travellers will be able to quickly access their ecological impact.

What is CO2e?

CO2 refers to Carbon Dioxide, while CO2e stands for Carbon Dioxide Equivalent. It is the standard in the Sustainability Industry for carbon reporting. This measure considers the IPCC’s six (6) recognised greenhouse gases, as well as radiative forcing (RF) for aviation. Discover more about CO2e and its importance - here.

Why Thrust Carbon?

Our partnership with Thrust Carbon allows Kudos to adopt a combination of methodologies such as ICAO and DEFRA for the calculation of CO2e emissions for air. Their ability to provide data for the following made them a green partner of choice:

  • An array of factors for calculations including a clear distinction in radiative forcing (RF) for air travel.

  • Data is extrapolated for air, hotels and car rentals globally with CO2e calculation in line with others.

  • DEFRA’s methodology is well-argued and included in substantial reports published by the government organisation, thereby reducing the risk of commercial interference.

Emissions Calculations

✈️ Air

A rich dataset is utilised for CO2e emissions of flight segments including route, flight number and distance, aircraft type, class of travel (cabin) and load factor. Additionally, considerations for take-off, landing, circling and non-direct routes, are done as this can result in emission factors being multiplied by 1.08, also known as the uplift factor (page 78).


Thrust Carbon

atmosfair (VDR)



Class of Travel





Flight Distance





Aircraft Type





Radiative Forcing





Seating Layouts





Load Factor





VDR (Verband Deutsches Reisemanagement) – the German Business Travel Association.
X Not applied, or average applied for all inputs
Aircraft Type: Thrust Carbon (2018 + regression analysis) | atmosfair (2018 + computer simulation) | ICAO (until 2018)

Load factor?

The load factor is the percentage of seats flown. Airlines with lower load factors have higher ‘per-passenger' emissions since the emissions are split between fewer people. Thrust Carbon’s calculations attempt to adjust according to the average load factor of the airline in the year that you fly.

Distance vs Adjusted Distance

Sometimes when the distance between two (2) locations is calculated, an adjusted distance will be included. This is because rarely is travel in straight lines such as a flight navigating in closed airspace or a circle at an airport, and trains will zig-zag between hills and mountains.

Radiative Forcing

High altitude causes the nitrous oxide and water vapour emissions of aircraft to have a compounding effect on the climate. This is known as radiative forcing, and therefore essential to include it by way of a radiative forcing multiplier to have a true understanding of the impact flying causes. As such, all air travel will have the relevant radiative forcing multiplier applied.

🏨 Hotel

Thrust Carbon’s Hotel dataset allows the most appropriate method to be used for hotel emissions.

Hotel Carbon Measurement Initiative (HCMI)

The Hotel Carbon Measurement Initiative (HCMI) is run by the Sustainable Hospitality Alliance and
provides a consistent methodology and tool that hotels can use to measure their carbon emissions. In particular, the tool gives an output of:

  • Carbon footprint per occupied room on a daily basis; and

  • Carbon footprint per area of meeting space on an hourly basis.

Unlike other methodologies - such as the CHSB - using HCMI data is the only way to accurately report carbon emissions on a per-property basis.

Cornell Hotel Sustainability Benchmarking Index (CHSB)

When a hotel’s HCMI calculation is unavailable, the fallback is the Cornell Hotel Sustainability Benchmarking Index (CHSB). This is an annual study that takes the HCMI data from over 20,000 hotels around the world. It is the only study of its kind and is considered the best-in-class for calculating hotel carbon emissions within a region. The CHSB provides sustainability data for a country/state/city, in addition to at times a breakdown by hotel quality.

Thrust Carbon Hotel Sustainability Index (TC-HSI)

Additionally, a dataset comparing properties in the same city is available which is provided via the Thrust Carbon Hotel Sustainability Index (TC-HSI). Thrust Carbon has ranked every hotel in the world in order to deliver a unique metric, a score out of 100 with 100 being the highest rating. This takes into account tiered datasets and weighted scoring, applied across metrics such as:

Carbon emissions

Sustainability certifications

Net-zero commitments

Renewable energy usage

Carbon tracking

Efficient lighting

Single plastic use


Plant-based meal options

Responsible sourcing

and more

This is the only tool of its kind that enables point-of-sale hotel sustainability ranking.

🚗 Car Rental

The base methodology for car emissions is the DEFRA (Department for Environment, Food & Rural Affairs) model.

Unfortunately, similar high-quality models are not available in other nations. There is also a data gap where the exact car type rented is rarely recorded, so it is not possible to use WLTP (Worldwide harmonised Light vehicles Test Procedure) figures for a car’s journey. It is an area of active research for Thrust Carbon that is anticipated to result in developments in upcoming methodology versions.

What is WLTP?

The Worldwide harmonized Light vehicles Test Procedure (WLTP) is a global standard for determining the levels of pollutants, CO2 emissions and fuel consumption of traditional and hybrid cars, as well as the range of fully electric vehicles.

Industry-standard car rental car type codes (ACRISS) are converted into car types (e.g. SMMT) supported by leading methodologies (e.g. DEFRA). CO2e emissions are based on the location, car type and duration of the rental. In the absence of actual distance travelled, a distance multiplier is applied that utilises an average distance travelled per day.

What is 1 ton of CO2e?

Thrust Carbon’s intuitive API will enable our platform to provide relatable sustainability equivalents, such as the number of plastic bags produced that would result in the same carbon emissions.

Visual of 1 ton of CO2 (volume 510m3), by Carbon Visuals.

🍃 Discover more about the impact travel has on the environment and the travel platform’s offerings that can help combat this, in the following articles.

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