This week, the US Energy Information Agency (EIA) released a report on the carbon dioxide (CO.)2) emissions from every state between 2000 and 2015. The good news? CO2 emissions fell in 41 states, with Maine taking home the prize for the largest percentage drop in emissions (by 25 percent). Ohio, meanwhile, showed the largest absolute decline, with 51.7 million fewer metric tons of CO2 emissions in 2015 than in 2000.
The bad news? Nine states saw CO . rises2 emissions in the same period. Nebraska was one of the worst offenders, with a 22 percent increase in carbon emissions between 2000 and 2015. Although Nebraska’s population grew by about 200,000 in those 15 years, Kansas also welcomed about 200,000 people into its territory between 2000 and 2015. state. reduce emissions by 17.2 percent. (Kansas’ success is likely due in part to the state’s adoption of wind, where “wind power has grown from less than 1 percent of net electricity generation in 2005 to 24 percent in 2015, making wind the second-largest energy provider in the world.” the state is, after coal,” writes the EIA.)
However, the EIA cautions against evaluating these emissions numbers as a direct reflection of how green a state is, as the agency only counted energy-related emissions in the state where they were created. That doesn’t take into account the export of energy across state borders. If a state uses only renewable energy sources, but buys a significant amount of electricity from a coal-fired power plant in a neighboring state, the neighboring state bears the burden for all those emissions.
Weather, Driving, Resources
While the end-period data is now three years old (unbelievably, we’re now living in 2018), looking at 15 years of data can help spot interesting trends and help industry and policymakers address problem areas. Transport and heating are often persistent problems for CO . try to reduce2 emissions, especially in states where commutes are long (thus using a lot of gas) and in cold, rural states (where heating is critical, but economies of scale from heating densely populated apartment buildings do not exist).
Per capita emissions data can sometimes reflect this. The EIA distributed the total CO . from every state2 emissions by the number of people in the state. In 2015, Wyoming, North Dakota and West Virginia filled the top three slots. Although those three states have relatively few inhabitants, they are also heavily dependent on fossil fuels. But there’s certainly another factor at work: the states are also in colder climates, and driving is a primary mode of transportation, further increasing emissions per capita.
Although Texas has the most CO. emitted2 in 2015 it also had by far a low per capita emissions rate as millions of people live there, and the mild winters mean there is no need to burn fuel for heating. The EIA also noted that New York had the lowest per capita CO2 emissions of the 50 states.
Although New York is also in a cold climate, its dense population center means less heat is needed per person in winter (apartments offer economies of scale in terms of heating). Less energy is needed for transport because a dense population can rely on a public transport system and avoid driving. In addition, “New York’s economy is focused on low-energy activities, such as financial markets,” the EIA wrote. “New York, for example, accounted for about 6 percent of the U.S. population in 2015, but consumed only 1 percent of the country’s industrial energy.”
Much of the work to reduce state carbon emissions took place toward the end of the 15-year period. (You can see a breakdown by year of emissions estimates in Table 1 of the EIA State Analysis Report here (PDF). Year 2000 and years 2005-2015 are shown). In many states, CO2 emissions increased between 2000 and 2005.
Over the past decade, falling prices of wind and solar installations, along with state and federal policies to encourage the adoption of renewable energy, have contributed to the growth of low-carbon and zero-carbon technologies. The EIA makes no attempt to correlate policy with CO2 emissions reduction (although Ars wrote about a recent study that did that here). But the agency is breaking through the change in the renewable energy mix for some of the most densely populated states with lower per capita emissions.
Hydropower and nuclear power were the two main sources of carbon-free electricity in 2000, but the EIA notes that almost no new hydropower or nuclear power has come online since then. Instead, we’re seeing an astonishing amount of wind generation come online in Texas in 2015, with Illinois, Pennsylvania and Washington also adding significant winds. In fact, California saw total zero-carbon electricity generation decline between 2000 and 2015, largely due to a drought that reduced hydroelectric power in 2015, as well as the retirement of nuclear power. Wind and solar took much of the slack in 2015, but not enough to show a net gain in renewable generation.
That should tell us that the gains the US made in cutting carbon dioxide emissions between 2000 and 2015 are not guaranteed to continue into the future. As older nuclear plants across the country retire, a concerted effort must be made to replace that carbon-free electricity with new carbon-free electricity. Heating systems must become more efficient and fuel economy must be a priority for car manufacturers.