CO2 calculations

Traveling is great and brings a lot of benefits, like disconnecting from your everyday life, meeting new people, getting the chance to try new things, understanding better other cultures and creating lifetime memories.

Unfortunately, it does have some disadvantatges as well.

One is that it can be quite expensive. Travelinho aims to help with this one by finding alternative combinations that allow you to save money.

Another one is the environmental impact that traveling causes, mainly due to transportation. Of course, to stop traveling is not an option. In order to help here, we thought that the best we could do is raising some awareness. Do you have even a rough idea of what is the footprint of a trip? Probably not; and that is normal. We did not know either not so long ago.

The idea is that when one decides how to travel, it has information about price, duration, departure time, arrival time and quantity of stopovers, among others. Then, depending on the priorities of each traveler, one alternative will be more appropriate than another one. But it is seldom among travel search engines that information about CO2 emissions is given. And without this information, how is a traveler supposed to take it into account?

This is why Travelinho includes an estimation about the CO2 emissions for each trip. You are able to sort the results by "Greenest", and then the CO2 emissions will appear.

Calculating the CO2 emissions can be very complex, as many factors have an impact. Unfortunately, it is very difficult or even not possible to get the values for all the factors. Therefore, we have decided to simplify it and take as a reference the European Environment Agency. This gives an average of grams of CO2 per passenger kilometer for each transport mode.

The calculation steps look as follows:

• We calculate the emissions for each segment, taking into account the transport mode and the linear distance between origin and destination.
• When possible, we try to adapt the value to make it more accurate.
• Finally, for each alternative we sum all the segments and display the total amount of estimated CO2 emissions.

It is important to highlight that this is only an estimation. We will try to improve the calculations by considering additional factors when possible. For more accurate calculations we should take into account:

• Exact distance covered. This is specially important for ground transportation, since roads and railways always need to adapt to the geography and never follow a straight line.
• Transfers between stations. If a transfer between stations is needed, for instance, between a train station and an airport, this also causes additional emissions.
• Vehicle model. There are models that are cleaner than others, thus emiting less CO2. This applies for all modes of transportation.
• Electricity mix production. Most of the trains are connected to the electrical grid. The CO2 emissions for the use of electricity depend on the electricity mix production, that is how much electricity was produced with gas, with nuclear power, with renewable energies, etc.
• Load-factor. The quantity of passengers inside a vehicle plays also an important role. The same vehicle will emit less CO2 per passenger if it is full.

If you are concerned about your carbon footprint, apart from taking conscious decisions to reduce it as much as possible, you can take further steps to compensate the emissions caused.

The 2 following organizations are specialized in supporting projects that reduce the quantity of CO2 emited:

• myclimate
• atmosfair