Why don't hotels tell us their carbon footprint?

According to a TripAdvisor survey, two thirds of travellers consider environmental credentials when choosing a hotel [1]. However, a similar two thirds say they find this difficult because they do not have enough information. TripAdvisor have said they will set up a rating scheme based for hotels based on their environmental practices - do they have energy efficient lighting and appliances, do they reuse towels and so on. However, how do we know if these practices actually translate into significant environmental savings? There is a scheme for measuring the carbon footprint of hotels called HCMI (Hotel Carbon Measurement Initiative). This was set up with the support of hotel chains such as Marriott, Intercontinental Hotels Group, Meliá Hotels International and Red Carnation Hotels [2]. Corporate clients can ask the hotel for their carbon footprint when they make a booking so they can fill in their environmental accounts. So why don't they advertise this for individuals too?



The HCMI statistic is not perfect but it is a good start. It measures carbon emissions from energy use on the hotel premises plus laundry - if it is not possible to get real data for laundry carbon emissions use you just assume a certain amount of carbon/tonne. It does not include carbon emissions from other bought in services and equipment such as furniture. The hotel is divided into three parts - private areas (not counted), meeting room areas and the rest, assumed to be for hotel guests. Meeting rooms have a separate measure (carbon emissions/m2/hour) and the guest rate is measured as carbon emissions/occupied room/night. This includes all the hotel guest services such as restaurants and bars, laundry, and IT services as well as the rooms [3].

Cornell University School of Hotel Administration did a survey of over 1000 hotels in the US plus a few in London and China to see how they perform in terms of HCMI [4]. They grouped the hotels both by climate and by luxuriousness. Neither seemed to make much difference. There was much more difference within groups than between.

The chart below shows the range of HCMI for hotels in the US (all lumped together) and in the UK. The average UK person has a carbon footprint of around 30 kg CO2/person/day and the median hotel in the UK is 24 kg/room/day so for two people sharing that is rather less than half your normal footprint. There is hardly any difference between the median for midscale/upperscale hotels (25.1 versus 22.6 kg CO2) but there is a staggering difference between hotels in the same class with the worst hotels generating 10 times the emissions of the best [4].

Carbon footprint per occupied room night (HCMI) for hotels in the USA and UK. Median is marked by the dot and the range is marked by the lines. Numbers in brackets are the sample size. Data from [4]

Only a small part of these differences are due to climate. Hotels in San Francisco use similar energy to hotels in Denver, despite needing to cope with twice as much climate related heating and cooling, as shown in the chart. There does not seem to be any pattern relating climate and energy use.

Median energy use intensity related to degree days (heating plus cooling) for hotels in major US cities. Chart from [4]

Surveys suggest that when we choose a hotel to stay in we consider location and price as far more important than environmental impact. However, maybe that is because we do not have the necessary information. Given that hotels are already calculating HCMI for their corporate clients, there is no need for a new, complicated rating scheme from TripAdvisor. We just need for the hotels to tell us the HCMI.

Of course there are many other leisure services where it is hard or impossible to know what our carbon footprint is. What about theatres and cinemas, concerts and football matches?  Also quite a lot of us would like to know the carbon footprint of stuff we buy like cars, computers and clothes - which is why books like 'How bad are bananas' by Mike Berners Lee are so popular.  Transition Cambridge Energy group will be discussing this topic in June so hopefully I will have some more information for you soon.

[1] Survey: Two-Thirds Of Travelers Want Green Hotels. Here's How To Book Them. (Trip Advisor) 2013
[2] Major hotel groups welcome standardised approach to carbon measurement (Green Hotelier) 2012
[3] Hotel Carbon Measurement Initiative 1.0 methodology (Wyndham Worldwide) 2012
[4] Hotel Sustainability Benchmarking (Howard Chong and Eric Ricaurte, Cornell University) 2014