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US Electric Power Mapping

Target users

Anyone who are interested in the US power system



Realtime Board



My roles


Paper prototype

Usability testing


10 weeks




We visualized data relating to US power plants across the country.Our visualization includes two main panels: the US power generation and the state power generation. Through this visualization, users could explore the distribution of power plants in the US, filter out their interested technology/resources driving the power plants, and see the history of US power generation and technology evolvement. The visualization was published on Tableau Public.



On October 8, 2018 the Intergovernmental Panel on Climate Change (IPCC) issued the “Special Report on Global Warming of 1.5oC.” In that report, the IPCC stresses the importance of reducing the carbon footprint of the electricity sector.


Specifically, in order to achieve the goal of limiting global warming to 1.5oC: “renewables are projected to supply 70-85% of electricity in 2050 while the use of coal would be reduced to close to 0%.”In order to understand the implications of these changes, it is important to understand our current electricity mix, the role that renewables play in supplying electricity today, and understand how our electricity infrastructure evolved over time.

Our visualization aspires to enhance the understanding of viewers by showing them how electricity supply evolved in the United States between 1900 and 2018, and how it is projected to evolve until 2020.

Following is the process we have followed for designing this visualization. For detailed information on our data acquisition and handling, please refer to our Concept Production Report.

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Ideation and sketching


Each member of our group individually decided that some version of a map showing the distribution of power plants around the country and their capacity should be the centerpiece of our visualization. We used circles of variable size to indicate the location of power plants, the area would indicate plant capacity while the color will indicate the fuel type (e.g. coal vs hydroelectric). We also each focused on a different secondary aspect of the data which we will flush out and use as supporting graphics around the centerpiece map.


First, we became interested in the difference in generating capacity between summer and winter. We might choose a separate graphic - a line chart - showing the overall generating capacity as it shifts through the year, or we might simply reflect the difference in capacity in the central map and use a checkbox to toggle between winter and summer months. Secondly, we focused on the total capacity and distribution of generators throughout the history of the United States. This might be shown with an area chart underneath the main map. Finally, we chose to display a close-up of any state the user clicked on in a pane on the right hand side of the visualization. This will allow the user to closely inspect the data.

Low-Fidelity Paper Prototype

Based on the ideation sketches, we have created a low-fidelity prototypes for both nation panel and state panel (here we used WA as example):


Guerilla Usability Testing

We conducted usability testing of our low-fidelity prototype with 6 participants from both class and outside of class. Our goal is to test if the visualization presents clear and easily accessible information related to the U.S. generator and power, gain insights from the users, and figure out what is working well and what is not.


We asked users to finish three tasks using the paper prototype:


  • Check the power plants distribution in different years.

  • Check the distribution of certain technology in power source in both nationwide and specific state.

  • Find the dominant technology in power source in a certain state.


Here is the affinity diagram for the categorizing feedbacks and observations from our usability testing:

Low-fi Usability Testing Results.jpg


Based on the findings from usability testing, a few major changes have been made for the high-fidelity prototype:


Change 1: ​ Put the year slider in the middle with higher contrast color so that it is more visible to users

State Panel.gif

Change 2: ​ Added tooltip when hovering over a specific power plant including information as plant name, capacity and location (city/county) of the power plant


Change 3: ​ Added a chart of “technology history” to show the trend of individual technology


Change 4: ​ Added a search tool to let users find the state they are interested by search and filter out the state name



National panel


State panel


Overall, the visualization allows for both high-level overview of energy trends as well as detail information in single power plants. We created the navigation by following the widely cited visual information-seeking mantra: “Overview first, zoom and filter, then details-on-demand”, as users can have a big picture of power generation in the US using the US dashboard and then explore more details in the state dashboard.

Designed by Phyllis Liu in 2020. All rights reserved.

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