全球变化知识资源中心

The EPA’s state-based plan for regulating power plants’ CO₂ emissions is founded on section 111(d) of the Clean Air Act, which requires the EPA to set performance standards for stationary sources of pollution, including power plants, but also directs it to work with states in developing policies to help polluters meet those standards. Given that the EPA has previously used this section to set limits on the level of nitrogen oxides and sulphur dioxide emitted by power plants, many believe that the EPA will have ample authority to establish and require states to implement the type of level-based system for regulating carbon pollution described in its Clean Power Plan^{2, 3}. What seems less certain is whether states have the capacity to significantly decrease power plants’ carbon pollution.

Over the past two decades, states have created several policies that, in principle, could cut power plants’ level of CO₂ emissions. These policies range from those such as GHG targets that were primarily motivated to combat emissions to other programs such as renewable portfolio standards that were created for other reasons but, because they try to alter how energy sources are used or managed, have implications for plants’ climate-disrupting pollution^{4, 5, 6, 7}. For want of a better term, we refer to the latter programs as energy policies with climate implications. Scholars disagree, though, over whether these state initiatives are capable of reducing carbon emissions. Some argue that climate-focused policies and energy policies with climate implications can both be effective⁸. Others contend that only climate-focused policies can work⁹. Still others claim that both types are too constitutionally constrained or institutionally weak to have a significant impact¹⁰. Researchers have analysed the conditions under which states adopt climate-focused policies and energy policies with climate implications^{11, 12, 13, 14, 15}, their financial costs and benefits¹⁶, their implications for the development of low-carbon energy technologies^{17, 18}, their impact on the share of renewable energy electrification¹⁹, and their simulated effects on future CO₂ emissions²⁰. However, they have rarely assessed the effects that states’ policies have had on emission outcomes. On the few occasions they have^{8, 21}, scholars have investigated the effects of policies on the aggregate CO₂ emissions of states’ electricity sectors.

Consequently, researchers stop short of examining whether states’ policies reduce carbon emissions at the actual sites where electricity is produced and carbon dioxide is released—power plants. This despite other studies showing that within an industrial sector, some facilities pollute much more than others and organizational traits can affect emissions^{22, 23}. Studies that focus on state-level outcomes, therefore, ignore variation in power plants’ emissions. They also fail to address the possibility that the observed effects of states’ policies may be explained by features of plants themselves such as their size, primary fuel, pollution control equipment, dispatch systems, and whether they are publicly or privately owned²⁴. In addition to these internal characteristics of plants, there may be external factors or attributes of plants’ states and regions that determine the adoption of policies and thus could explain their effects. The association between emission outcomes and states’ policies may be due, for example, to the fact that some policies are easier to pass in states where the coal, oil and gas industries are weak, the Democratic party exercises more control, the potential for renewable energy is high, energy efficiency is a fiscal priority, cleaner fossil fuels such as natural gas have become more affordable, and the regional demand for electricity is growing^{12, 25}. Until research determines the net effects of states’ policies, it will be difficult for environmental officials to know which state policies produce effective and generalizable results.

Scholars have been slow to identify which state policies reduce CO₂ emissions at the level of power plants because systematic, plant-specific data on CO₂ emissions have largely been unavailable. Recently, though, the EPA began requiring power plants to submit information on their carbon pollution under its Greenhouse Gas Reporting Program (GHGRP). Using these data and other information on power plants and state/region characteristics, we conduct the first analysis of the effects of states’ climate-focused policies and energy policies with climate implications. To determine how states’ policies fared around the time of the recent recession, we use a lagged dependent-variable model that examines plants’ emissions in the year 2010, controlling for their emissions in 2005.

Table 1 lists the policies to be tested, the states that have adopted them, and how long they have been in place (as of 2010). This list approximates the range of measures that states have used to address power plants’ carbon emissions. The first set of policies, which are explicitly climate-focused, include emission caps (carbon dioxide performance standards designed to reduce CO₂ emissions), GHG targets (goals for reducing GHG emissions to a certain level by a certain date), climate action plan (comprehensive strategies for reducing a state’s CO₂ emissions), and GHG registry/reporting (systems that require plants to register and record their emissions and emissions reductions).

1. Carley, S. The era of state energy policy innovation: A review of policy instruments. Rev. Policy Res. 28, 265–294 (2011).
   • Article
2. Dunlap, R. & McCright, A. in The Oxford Handbook of Climate Change and Society (eds Dryzek, J., Norgaard, R. & Schlosberg, D.) 144–160 (Oxford Univ. Press, 2011).
3. Environmental Defense Fund, The Legal Foundation for Strong, Flexible and Cost-Effective Carbon Pollution Standards for Existing Power Plants (Environmental Defense Fund, 2013) http://www.edf.org/sites/default/files/111-clean_air_act-strong_flexible_cost-effective_carbon_pollution_standards_for_existing_power_plants.pdf
4. Bushnell, J., Peterman, C. & Wolfram, C. Local solutions to global problems: Climate change policies and regulatory jurisdiction. Rev. Environ. Econ. Policy 2, 175–193 (2008).
   • Article
5. Doremus, H. & Hanemann, M. Of babies and bathwater: Why the Clean Air Act’s cooperative federalism framework is useful for addressing global warming. Ariz. L. Rev. 50, 799–834 (2008).
6. Rabe, B. G. States on steroids: The intergovernmental odyssey of American climate policy. Rev. Policy Res. 25, 105–128 (2008).
   • Article
7. Pew Center on Global Climate Change, Climate Change 101: State Action (Pew Center on Global Climate Change, 2011).
8. Rabe, B. in Environmental Policy: New Directions for the Twenty-first Century (eds Vig, N. & Kraft, M.) 30–53 (CQ Press/Sage, 2010).
9. Michaels, R. National renewable portfolio standard: Smart policy or misguided gesture? Energy Law J. 29, 79–119 (2008).
10. Victor, D. G., House, J. C. & Joy, S. A Madisonian approach to climate policy. Science 309, 1820–1821 (2005).
    • CAS
    • PubMed
    • Article
11. Lutsey, N. & Sperling, D. America’s bottom-up climate change mitigation strategy. Energy Policy 36, 673–685 (2008).
    • Article
12. Lyon, T. P. & Yin, H. T. Why do states adopt renewable portfolio standards? An empirical investigation. Energy J. 31, 133–157 (2010).
    • Article
13. Jenner, S., Chan, G., Frankenberger, R. & Gabel, M. What drives states to support renewable energy? Energy J. 33, 1–12 (2012).
    • Article
14. Matisoff, D. The adoption of