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While energy efficiency of major U.S. coal-fired electric plants rose, carbon dioxide emissions did, too, researchers find

If electric utilities can burn less coal for each kilowatt-hour of electricity produced, they should also emit less carbon dioxide overall. That鈥檚 the rationale behind a proposed federal rule designed to decrease power-plant emissions by improving their energy efficiency.

But greater power-plant efficiency corresponds with more鈥攏ot fewer鈥攅missions, a team of researchers led by a 麻豆官网 professor has found. Among the power plants that produce 90 percent of the nation鈥檚 electricity, those that improved their energy efficiency also emitted more carbon dioxide, the researchers concluded.

As part of its Clean Power Plan, the EPA proposes that U.S. power plants adopt measures to improve heat-rate efficiency. Grant, along with the three other authors, investigated whether these measures would actually produce the desired effect: releasing less carbon dioxide.

Don Grant, a CU-麻豆官网 sociology professor who also chairs his department, was the lead author in a study published late last year on the paradoxical effects of the efficiency measures proposed by the U.S. Environmental Protection Agency (EPA). The study appeared in the journal听.

As part of its Clean Power Plan, the EPA proposes that U.S. power plants adopt measures to improve heat-rate efficiency. Grant, along with the three other authors, investigated whether these measures would actually produce the desired effect: releasing less carbon dioxide (CO2) into the environment.

Grant and his colleagues find that improving heat-rate efficiency, as the EPA recommends, lowers CO2 emission rates but increases emission levels. Such 鈥渞ebound effects鈥� raise questions about the efficacy of this efficiency initiative.

Sociology may not be the first field one might expect to find a study on CO2 emissions from power plants. Grant explains that sociologists have long been interested in environmental justice and communities鈥� exposure to industrial toxins.

Only recently have sociologists gone the next step to examine climate justice and the effects of measures like efficiency on carbon releases from power plants. Grant says sociologists have been criticized for not studying these issues and are now responding by examining how energy is organized, produced and creates environmental consequences.

According to Grant, sociologists and other social scientists can no longer afford to ignore these issues because the 鈥淓arth鈥檚 life-support system is literally at stake.鈥�

Funded by a National Science Foundation grant and furnished with data on U.S. power plants emissions by the EPA, Grant and his colleagues studied the determinants of plant emission rates and levels in 2010 compared to rates and levels in 2005.

The 1,129 power plants in their sample compose roughly a third of all U.S. power plants. The Greenhouse Gas Reporting Program (GHGRP) included these power plants in the dataset because they met EPA criteria as 鈥渕ajor source鈥� polluters.

The 1,129 plants in this sample produce 90.1 percent of all carbon dioxide emitted by the electricity sector, according to Grant鈥檚 study.

By comparing thermal efficiency of plants, Grant and his colleagues found that the more efficient a plant is at preventing heat losses, the more effective it is at preventing carbon releases per unit of electricity generated.

However, efficiency improvements have the opposite effect on a plant鈥檚 overall emission levels. This runs counter to what the EPA is trying to achieve and suggests that as it becomes more economical for plants to create electricity, they will increase their output to the point that their overall carbon emissions actually grow.

This is problematic to Grant, because he strongly believes future generations will be concerned with the reduction of overall emission levels, not the rate at which emissions are produced.

Grant ties this back to environmental justice: Current plants may be responsible for CO2 emissions today but won鈥檛 reap the consequences of their actions.

The basic flaw with the EPA鈥檚 current proposed measure is that emission levels from power-plant smokestacks are not initially being used as the standard, Grant contends. However, The EPA and Clean Power Plan also have the option to move toward a standard based on the level of emissions.

Grant notes that efficiency measures are not necessarily bad. Instead, policymakers must make sure they have the same effects on both emission rates and emission levels. If the EPA is going to support efficiency measures, it needs to pay attention to their potential 鈥渞ebound effects,鈥� Grant says.

While some scholars assume efficiency improvements always produce rebound effects, Grant holds out the possibility such improvements may yield positive outcomes.

The basic flaw with the EPA鈥檚 current proposed measure is that emission levels from power-plant smokestacks are not initially being used as the standard, Grant contends. However, The EPA and Clean Power Plan also have the option to move toward a standard based on the level of emissions.

鈥淢y hope is that they will eventually adopt such a standard,鈥� says Grant.

Since this study was published, Grant received an additional grant from the National Science Foundation to study power plants worldwide, to determine whether 鈥渞ebound effects鈥� occur in other countries.

Grant and his colleagues are investigating what organizational, economic and normative factors explain why power plants in certain countries are more susceptible to 鈥渞ebound effects鈥� than others.

This is where sociologists have a place in the discussion. They analyze how businesses are structured differently, the effects of international trade, and the consequences of laws and policies. Grant鈥檚 latest study looks at all the power plants in the world. He was furnished with a very detailed dataset, and he and his colleagues are mapping the laws and treaties each plant is exposed to in order to determine which plants are doing a good job monitoring both emission rates and levels.

The reaction to his studies has been mixed, says Grant. Critics of energy efficiency find the results compelling. However, fields like engineering are slow to accept them, possibly because they have a greater vested interest in developing more efficient energy technologies.

Whether the 鈥渞ebound effects鈥� associated with highly efficient power plants are large enough to cause the nation鈥檚 total CO2 emissions to increase is open to debate. But Grant and his colleagues stress that as the United States emerges from a recessionary period, demand for electricity will likely grow, thus increasing the odds that 鈥渞ebound effects鈥� will occur, and overall CO2 emission levels will rise.

At this point, the proposed EPA policy is being contested on legal grounds as some industry groups are trying to upend the Clean Power Plan. The decision on whether these efficiency measures will go into effect will be made June 30 of this year.

Assuming they will, Grant hopes that his studies of power plants will encourage the EPA to quickly adopt an emissions-level-based standard for evaluating the effectiveness of efficiency measures.

Magdalena Rost, a student majoring in classics and English, is an intern for Colorado Arts & Sciences Magazine.