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Make an Impact Carbon Calculator
The Center for Climate and Energy Solutions (C2ES) works to advance policy and action on climate change issues. The organization carries out direct intervention with carbon-conscious consumers through some of it's partners using it's carbon calculator. One of the most advanced carbon calculators in the world, capable of carrying out complex computations across multiple countries, they came to Trellon to build out the core technology that drives their platform.

There are a lot of carbon calculators out there, but few are technically sophisticated enough to perform interventions on a worldwide scale. C2ES came to Trellon looking to create an online carbon calculator that can handle the nuances of measurements in different contexts and cultures. This was more than a technical challenge, this system was designed to reflect their role as a credible actor in the global dialogue about climate change.


Designing this carbon calculator was no simple task. It was a complex design and technical challenge that involved considerations at multiple levels. First, the system had to provide personalized recommendations to people using the system. This meant it needed to be aware of where someone lived, and use the correct data set to make estimations. Second, the system needed to use the most up-to-date, correct information. This means the data sets need to be stored in a way where they can be updated over time, to carry out the complex calculations that are necessary to provide accurate information.

We created a set of requirements for the Make an Impact carbon calculator that looked similar to the following.

  1. Customizable: the system supports multiple calculators that ask questions customized for specific contexts and cultures.
  2. Multisite: the system supports multiple calculator sites, each one with a customized look and feel.
  3. Personalized: the system provides personalized recommendations for participants based on the information they provide.
  4. Verifiable and Updatable: Information needs to be updated often, and the system should provide tools for verifying the data.
  5. Reporting: the system is capable of providing global metrics that can be filtered by country, partner, region, and other factors.
  6. Multilingual: the system is capable of providing calculators in multiple languages.


Trellon provided strategy, design, development and support services as part of this engagement. We worked closely with stakeholders at C2ES to create a multisite platform capable of fulfilling the requirements, then implementing it as part of multiple websites.

Multisite Portal

Trellon created a portal solution for the carbon calculator using Drupal. Administrators are able to create new calculator sites using web-based administrative tools that require little setup. Each site contains a copy of the most recent data and a default set of questions for estimating someone's personal carbon footprint. Each site also contains a set of reports for understanding the kind of impact that is being had in the site. The data collected from each site can also be reported on in aggregate from a main site.

The system allows administrators to create multiple versions of the calculator (such as simple and advanced), which can be used to collect data from participants. Administrators can add or remove indicators, modify the order in which they appear, and update the way data is calculated through a web-based administrative interface. All of this is done without changing the core set of indicators used to assess someone's carbon footprint, providing great flexibility in how data is collected.

Data for carrying out calculations is stored in a set of fact tables, with information and indicators categorized by country. Data for each site is kept up-to-date by updating the fact tables, which are made available to each site in the system. This allows C2ES to maintain a current set of data across all sites at all times.


Participants are provided with personalized recommendations based on the responses they provide to indicators used in the calculator. These indicators are stored over time, and participants can come back to track changes in energy consumption as part of a plan for reducing their own carbon footprint. Email and other communications tools are used to remind people to participate, and keep them on track towards their personalized energy goals.

The recommendation engine itself can be customized, allowing administrators to add new recommendations in response to indicators falling outside certain thresholds. This allows the organization to develop curriculums specific to individual contexts and cultures, and to remove items that would be considered irrelevant in some areas.

Internationalization and Reporting

The entire portal is internationalized. Each site can be deployed in one of multiple languages, where the interface and content is translated into the language selected by the user.

Reports on reductions in carbon footprints are available on a global, country and site specific level. There are over 10 reports that are used within the site to understand participation, reductions and other key metrics about participation. These metrics can be further filters by specific organizations to provide a set of metrics appropriate for distributing to specific partners.