Stories of American Energy Use


Even the preliminary analysis he has done with Vulcan so far fascinates him. As a case in point, he talks about ranking the top twenty counties with the highest emissions.

“The first thing you see,” says, Gurney, “is that virtually no part of the country is un-represented.” There are pockets of high emissions all over the country. And the counties with the highest emissions are often, but not always, places with large populations. In some cases, a busy interstate highway through a mostly rural area or a power plant that supplies electricity to other counties (even other states) is enough to push a county up in the rankings.

  • American Carbon
  • Introduction
  • Stories of American Energy Use
Graph of  top 20 carbon emitting counties in the United States.

Even in counties with similarly high population densities, the processes causing high emissions aren’t always the same. “Consider the top three counties,” says Gurney. The first encompasses the Houston area, the second, Los Angeles, and the third, Chicago. On the one hand, it isn’t a surprise that such densely populated places make the list of the largest emitters in the country. On the other hand, Gurney finds it interesting that they each have different reasons for being there.

“Around Houston, it’s industrial emissions that pushes them to the top of the list. In Los Angeles, it’s cars. In Chicago, it’s residential and commercial heating—because the temperatures are cold and the houses and buildings are old.”


Nearly all parts of the country are represented in a ranking of the top twenty counties with the greatest carbon dioxide emissions. (Graph by Robert Simmon, based on data from the Vulcan Project.)

Graph of top 3 carbon emitting counties, by sector.

Each of the counties in the list of top three emitters has different mix of reasons for being there. Around Houston, industrial emissions, mostly from oil refineries, are over 10 megatons of carbon per year. Los Angeles’ industrial emissions are less than half of Houston’s, but its mobile (vehicle) emissions are more than double. The large number of old, poorly insulated buildings in Chicago, the Windy City, elevate the city’s commercial and residential electricity consumption, pushing the county’s emissions to number three in the nation. (Graph by Robert Simmon, based on data from the Vulcan Project.)


To Gurney, the inventory isn’t about calling places out for bad or good carbon behavior. “It’s really a story about American life, about how people live in different parts of the country, what their energy needs are and how they meet them.” This story is fundamental to deciding the most effective and realistic strategies for reducing emissions that cause global warming.

Some stories appear straightforward and predictable. A graph of daily carbon dioxide emissions traces out the American work week: emissions are consistently higher Monday through Friday, dropping on Saturday and again on Sunday, as the population takes a rest day.

Bar graph of daily carbon dioxide emissions showing the weekend effect.

Other stories appear simple on the surface, but could have multiple underlying themes. Tallying up emissions on a weekly basis over the course of a year reveals a distinct summer time peak. Scientists will have to analyze the inventory more carefully to determine the reasons for the seasonal patterns. Is it because, as a nation, we use more electricity to cool our homes and businesses than to heat them? Or is it that we travel more in summer?


A graph of daily carbon dioxide emissions for several months document the familiar story of the American work week. Emissions are higher on weekdays, when more people work and more businesses are open, and they hit a weekly low on Sundays. (Graph by Robert Simmon, based on data from the Vulcan Project.)

Graph of weekly carbon emissions.

Having the data to start to answer these questions has given Gurney new enthusiasm for the project. “We have devoted so much time to building the system and all the tedium that goes with it, and now we get to do exciting stuff. I am really more excited about the project now than I was at the beginning,” he says.

From Vulcan to Hestia: A “Science 2.0” Test Case?

Gurney is also intrigued with the potential for the Vulcan project to explore questions that fall more under the domain of social, as opposed to physical, science. Among them, how might scientists use the Web to tap local expertise to expand on or quality-control science data sets? When his group announced the release of the Vulcan inventory, they created a Website where they solicited collaborators. Dozens of people, from environmental groups to employees of state and local regulatory agencies, contacted Gurney through the Website, sharing data and local expertise that may improve the inventory’s quality.

Gurney admits that the “Science 2.0” approach (using wikis, blogs, and other Web 2.0 technologies to allow easy, global-scale collaboration) has its limitations, and isn’t suitable for all kinds of science—”Obviously, you couldn’t do high-energy physics this way”—but it’s something he wants to explore.

That kind of approach will likely play a big part in the next phase of his project, which his team is calling Hestia, after the ancient Greek goddess of the hearth. The team plans to find partners in industry, government, non-governmental organizations, and universities around the world to create a global fossil fuel inventory that drills down to the scale of urban neighborhoods. Anyone on the Web will be able to access it through an interactive, three-dimensional visualization of the Earth.

With a project so ambitious, they’ll need all the collaborators the Web can bring them.


Weekly totals of carbon emissions peak in the summer at over 30 megatons. This summertime peak may tell more than one story about American life and energy use. Perhaps it is because Americans travel more in summer, or because we use more electricity for cooling than heating—and perhaps there are different reasons for different areas. Gurney and other scientists can use the database to better understand how American energy use changes from place to place, from season to season, day to day, even hour to hour. (Graph by Robert Simmon, based on data from the Vulcan Project.)