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Carbon Card

Paymentsystem to calculate carbon footprint




The Exerzierplatz is a very central and historically charged place located on Holtenauer street in Kiel. Besides being used as a parking lot, there is also the weekly market. There is a stark contrast between low and high carbon lifestyles in the same location. Most of the products in the weekly market are bio vegetables , they are supplied from nearby farms, so they are more environmentally friendly. Such a low-carbon lifestyle should and is becoming a new trendy lifestyle for nearby residents.


A payment system designed specifically for the weekly market in the Exerzierplatz. A combination of physical cards and virtual apps to calculate and analyze carbon footprints based on digital transactions. In this way, users are not only educated about the environmental impact of their transactions, but also provided with a simplified, engaging and user-friendly visual representation of the data.


Visualize carbon footprint. The system visualizes the carbon emissions of food across the supply chain. And according to the data website provided by the University of Oxford, the carbon footprint of food is divided into low-carbon, medium-carbon and high-carbon.Different colors represent different foods.


1.Mission Statement

2.Definition of  Target Groups

By brainstorming I created the basis to put together a mission statement.

Design thinking:

Significance: What is the Significance of Understanding the Carbon Footprint?
Technology: Is calculating carbon footprint achievable?
Business: How to attract more customers to the low carbon market?
‍Target Groups: How would we describe our target audience?
Impact: What tangible impact do we have on others?

In order to empathize with the different types of users, I developed so-called proto-personas, which are based purely on experience and assumptions. These serve as a starting point to reflect on the needs and challenges of the user and possible solutions that can be considered later in building the information architecture.


By observing and visiting in the market, we have drawn different user profiles. In general, the users who come to buy are conscious of low carbon and environmental protection.However, the lack of clarity and inability to quantify data information has also become a doubt for customers.

3.Setting Goals

By brainstorming and prioritizing ideas in awareness (“How to make people aware of the importance of carbon emissions from food?”) and ideas (“How to quickly understand the carbon emission data of food?”), I quickly came to a roadmap with the next steps, focusing not just on the app, but also on the organization itself – I believe that a strong organization is more likely to create strong products and services.


Scientifically calculate the carbon footprint of each link to improve users' trust in low-carbon products, thereby encouraging more consumers to buy low-carbon products.



Value Proposition

To understand the old site and its content, I ran a content audit listing all available information and features. Based on this, I decided what to keep, what to kick and how content can be integrated into a more intuitive information architecture.


Evaluation via Tree Tests

To ensure an intuitive understanding of the site‘s structure I tested the sitemap on-site with potential users through so-called tree-testing by giving them relevant tasks, such as "Where would you click if you wanted to join a theatre group?" Based on the test results, the sitemap has been adjusted accordingly.


Main Functions

1.Scan to obtain product information/carbon footprint emissions in each supply chain process/carbon emission level: low carbon, medium carbon, high carbon food

2.use carbon credits to redeem money / check the receipt to compare the price of low-carbon products and ordinary products / receipt of carbon emissions per purchase

3.Food can be inquired and ordered in advance

UI Design

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