Imagine and suggest solutions to mayors and citizens to reduce CO2 emissions and the environmental footprint of our cities!

JOIN THE DECARBONATHON from Decarbonathon on Vimeo.

Your mission is therefore to imagine and suggest solutions that could have a positive impact on the carbon footprint of our cities and can be easily activated by mayors and/or citizen.

Lots of citizens wish indeed to do something about climate change but most of the projects and initiatives regarding climate change they face either relate to international discussions, awareness campaigns, large financial means being pulled together to act, or new technologies being developed in the industry.

The Decarbonathon aims at providing them with solutions they can take over, based on new technologies and/or simple ideas.

Your goal? Offer innovative carbon-reduction solutions that can be applied in the next 2 to 5 years.

To do this, your project must fall under one of the following 4 topics:


Urban Mobility

The transport sector has a big impact on global emissions: around 14% of total global greenhouse gas emissions came from this sector in 2010[1], and is set to rise with increasing global passenger and freight activity. This challenge targets two approaches:

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1) Monitoring emissions

There are around 800 cities worldwide recording their greenhouse gas emissions within inventories in order to track and ultimately manage and lower their emissions impact.

However many cities find it difficult to complete the transport section of their inventory. Some may use fuel purchase as a proxy, others license registrations as proxies for modelling their cities’ transport emissions, however large uncertainties are linked to these kinds of methods. Mounting emissions sensors to capture transport data can be expensive and might be used as a sample method but is less likely to done a city scale-basis.

This challenge is directed at finding cheaper, better, or more accurate ways of measuring transport emissions: “Create a new product, technology or service that significantly improves the ability of cities to track the carbon dioxide emissions associated with transport use in the city boundary.”

2) New product, technology or services reducing emissions

Alternatively, the challenge is directed at proposing an easy-to-implement way of reducing transport emissions, for example: Electrical Vehicles smart charging, multimodality, door to door solutions and well being in transport modalities.

“Create a new product, technology or service that facilitates the integration of clean mobility solutions in the city boundary.”

Buildings and construction

The building sector (whether residential or commercial) accounts for as much as 18% of global emissions in 2010[2] .  The sector has a slow turnover: once built, buildings are there for decades.  On the other hand, just for Europe alone, it is expected to have 400 million square meters of new facade per year.


More details

Whether for existing or new buildings CO2 emissions from the sector are linked to the energy consumption for heating, cooling and ventilation. Moreover; it also relates to fossil fuel consumption during the production of the building materials. Recently, valorisation of CO2 into building materials is emerging.

This challenge is directed at technologies that reduce CO2 emissions from new or existing residential (individual or collective) and commercial buildings (including building blocks) which are linked to:

  • Optimised heating, cooling and or ventilation systems (e.g. OPV applied to buildings or waste energy valorisation)

  • Integrated energy management systems (e.g. tools driving reduction or energy consumption, including local storage)

  • New building materials that reduce or valorise CO2 (e.g. plants, cement valorising CO2)

  • Interaction with customer with a view to modify its behaviour (including demand side management)

 [2] World GHG emissions flow chart, 2012, World Resource Institute


A socially responsible energy production and consumption 

The energy production & consumption at a district level covers a wide range of technologies and implementations. It encompasses distributed energy, energy efficiency, circular economy; or short: “district energy systems”.

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This challenge is directed at technologies which reduce or avoid fossil fuel consumption at the level of a district and which are linked to:

  • Circular economy (whereby a waste can become a material or energy source) e.g. valorization of waste energy

  • Optimised electricity, heating, cooling, lighting and or ventilation systems (either by improved/new technologies or by new services based on functional economy principles that allow for instance to share and mutualise uses)

  • Energy management systems, including energy flow management across renewable producing and consuming buildings

Open category

Any innovative initiative that helps to reduce the carbon footprint of cities.


As you can see, this is an open-ended list of ideas to reduce our CO2 emissions ! So, keeping in mind that your solution must be feasible and rapidly deployable and touch citizen directly (their rapid adoption of your solution must have an impact), enter the challenge and try to be as innovative as possible in order to be invited to Paris to defend your project !

Want to take part in a worldwide challenge and do something tangible for the planet ? Then join the participants in the Decarbonathon ! Enter right now for the challenge and become involved in a more responsible world !

If you want to share the word with your friends, share the #Decarbonathon hastag on social media.


On the occasion of COP21 which will bring representatives of over 190 countries together around climate issues, ENGIE, a world leader in energy headquarted in Paris, NPL, the British National Physics Laboratory, Climate-KIC, the EU’s main climate innovation initiative and INPI, the French patent office, and their international nework, are co-launching the world’s largest challenge on simple ideas that can be activated by mayors and citizen for the reduction of CO2 emissions!

This initiative is backed by the Young Global Leaders and Shapers Communities of the World Economic Forum . From 30 November to 11 December, Paris will be hosting the 21st Conference of Parties (COP21) with a single goal: reaching a new international agreement to limit global warming.

In the run-up to COP21, the sponsors will be acting for the planet by organizing the Decarbonathon!

The Decarbonathon is an international competition open to all where talented thinkers from around the world can offer innovative solutions to limit global warming by reducing COemissions in cities! The innovations that you suggest will then be sponsored by the competition partners in order to make them real and help save the environment!

If you do not know how to implement your idea, do not refrain from suggesting it.

What’s to win? 

Loads of prizes are up for grabs in this challenge (electric bikes, eco-friendly trips, Apple Watches...). But moreover, it is a unique opportunity to get invited to Paris and meet the sponsors of the challenge in order to work on and take your project further.

If your project is feasible and will have a fast and positive impact on the carbon footprint, the sponsors may even ask you to join their incubation process in order to deploy your solution in numerous cities around the world!

More than €30,000 worth of prizes is at stake!


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Waiting for selection
Teams of 1 to 6


  • 1Electric bikes
  • 2Eco-friendly trips
  • 3Parrot Zik 2.0 headphones
  • 4Smart Thermostats


  • Luke P.
  • Kévin Y.
  • Jonathan L.
  • Franck P.
  • Florent V.
  • Bertrand G.
  • Muhammad Ather A.
  • Julien C.
  • Pierre M.
  • Anouck A.
  • Suchit B.
  • Sadia H.
  • Luciano H.
  • Bansel M.
  • Laura S.

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