Measured by environmental impact and economic importance, the electricity industry is one of the most important sectors of the American economy. The generation of electricity is responsible for 38 percent of all U.S. carbon dioxide (CO2) emissions and one third of all U.S. greenhouse gas (GHG) emissions. This sector is the largest single source of these emissions. It is also the largest source of sulfur dioxide (SO2), oxides of nitrogen (NOX), small particles, and other air pollutants.
At the same time, electricity is critical to the U.S. economy. Recent annual national expenditures on electricity totaled $250 billion—making the electricity sector’s share of overall GDP larger than that of the automobile manufacturing industry and roughly equal in magnitude to that of the telecommunications industry. Expenditures alone, however, understate the importance of electricity to the U.S. economy. Nearly every aspect of productive activity and daily life in a modern economy depends on electricity for which there is, in many cases, no close substitute. As the most desirable form of energy for many uses, electricity use has grown faster than GDP. The Internet and computers would not operate without very reliable, high-quality electricity. Electricity also plays a major role in delivering modern comforts and easing household tasks, from running heating and cooling systems to washing clothes and dishes. It plays an even more important role in the commercial, manufacturing, and agricultural sectors, where it provides lighting and powers a variety of machines. In short, it is hard to imagine a modern economy functioning without large amounts of reliable, high-quality electricity.
The economic and environmental importance of the electric power industry is, moreover, likely to grow in coming decades. Electricity demand has increased steadily over the last three decades and is projected to continue rising in the future, despite ongoing improvements in end-use efficiency. The industry, meanwhile, has undergone dramatic structural changes over the last 10 years, moving from a system of monopolies subject to state price regulation to a mixed system that now includes some elements of market competition in many states. After declining for 75 years, electricity prices have risen since 1970, making expenditures for carbon control a difficult proposition in the absence of mandatory GHG policy. The uncertain state of electricity market restructuring efforts around the country, particularly since the California crisis of 2001-2002, has increased perceptions of investor risk and sharply raised the cost of borrowing for capital investments by investor-owned utilities.
In this context, reconciling growing demand for affordable and reliable electricity supplies with the need for substantial reductions in GHG and criteria pollutant emissions presents a significant challenge for policy-makers and for the electricity industry itself. Indeed, even if worldwide growth in demand for electric power ceased today, the industry’s current level of emissions is not sustainable. Stabilizing atmospheric carbon dioxide concentrations at twice the level of pre-industrial times is likely to require emissions reductions of 65-85 percent below current levels by 2100. Clearly, reductions of this magnitude can be achieved only by taking action globally and across all sectors of the economy.1 But the electricity sector will undoubtedly need to assume a major share of the burden—in the United States and worldwide—given its centralized structure and contribution to overall emissions.
This report explores the electric power industry’s options for reducing its GHG emissions over the next half century. Those options include new technologies that are still being developed—such as coal gasification with carbon capture and sequestration—as well as strategies that rely on existing technologies at different stages of commercial and technical readiness (such as nuclear and renewable generation), lower-carbon fuels (like natural gas), and efficiency improvements (both at the point of electricity production and end use). Many of these options, in addition to reducing CO2 emissions, also reduce conventional air pollutants.
Although a power generating plant has a lifetime of 30-50 years, low-carbon technologies could claim a substantial fraction of the generation mix by mid-century—in time to help stabilize atmospheric GHG concentrations within the next century or two. Some of these technologies, such as coal-based integrated gasification and combined cycle (IGCC) generation, still need to overcome basic cost, reliability, and market-acceptance hurdles; others, such as carbon capture and sequestration, have yet to be demonstrated on a large scale. Still others, such as wind, nuclear, or even (given recent fuel price increases) natural gas combined cycle power, are relatively well developed but face constraints in terms of siting, public acceptability, cost, or other factors.
Nevertheless, the analysis presented in this report suggests that substantial GHG reductions could be achieved by the power sector—without major impacts on the economy or on consumer lifestyles—through the gradual deployment of lower-carbon options over the next several decades. At the same time, more immediate emissions reductions can be achieved through lowering demand by increasing the efficiency with which electricity is used; substituting natural gas for coal; improving efficiency at existing plants including highly efficient combined heat and power systems at suitable sites; expanding deployment of renewable generation technologies, including biomass co-firing of coal plants; and through the use of carbon offsets such as forestry projects and methane capture and collection. These immediate measures can reasonably be expected to reduce electricity growth and expand low-carbon electricity production in the United States from its 28 percent share in 2003, while also reducing emissions from higher-carbon generators.
While initial steps to limit electricity sector CO2 emissions will have only a modest impact on total U.S. emissions, steady and deliberate efforts to promote long-term technological change in this sector eventually could produce significant climate benefits, given the industry’s share of current emissions. The dollar cost of achieving GHG reductions will depend to a significant extent on which of several possible technology pathways emerge as both feasible and cost-effective in the decades ahead. Increasing the efficiency with which electricity is used is important to any energy future. In one scenario, the successful commercialization of carbon capture and sequestration technology would allow for continued use of fossil fuels in combination with somewhat increased reliance on similarly priced wind resources. In another scenario, a new generation of nuclear technology proves acceptable and plays an expanded role in meeting future electricity needs. Future emissions reductions might need to be achieved chiefly through increased reliance on relatively more expensive natural gas and renewable energy. Some forms of renewable energy can certainly play a role, but just how large a role depends on a range of uncertain issues in terms of cost, technical performance, and power system architecture. A major scale-up of renewable energy would likely require a greatly enhanced transmission network and expensive energy storage technologies to compensate for the remoteness and intermittency of much of the wind and solar resource base. These issues will be resolved only through further research and expanded field experience.
In all cases, however, long-term reductions will be achieved at lower cost if climate considerations are incorporated into the industry’s investment decisions sooner rather than later. Building another round of conventional pulverized coal plants that comply with new pollution control requirements for SO2, NOX, particulate matter, mercury, and other toxic emissions, but that later need to be scrapped, or retrofitted with costly and inefficient CO2 scrubbers, would likely be the most costly path.
To ensure that climate considerations figure in the industry’s planning decisions and to provide effective market incentives for investment in low-carbon technologies, a clear timetable for the regulation of GHG emissions is essential. Many industry experts and utility executives see such regulations as inevitable over the next 10-20 years, but cannot—without some certainty about future regulation—justify added expenditures for low-carbon technologies today, either to their shareholders or to state regulators concerned about the local economic impacts of higher-priced power. Voluntary efforts to reduce CO2 emissions simply will not be sufficient in an increasingly cost-competitive and risk-averse market. If, however, GHG emission limits are implemented in concert with other pollution control requirements, long-term air quality and climate objectives will be achieved more quickly and at lower total cost than under a piecemeal approach.
Four major policy recommendations emerge from the findings in this report concerning prospects for a long-term transition to a low-carbon electricity power sector: