Ben Parry
Brian Perusse
Scott Siler
The intent of this paper is to rebut specific findings in the Energy Information Administration's (EIA) report, "Federal Financial Interventions and Subsidies in Energy Markets 2007," which analyzes federal subsidies to electricity producers. The report provides a thorough review of federal subsidies allocated to electricity producers in 2007, based on the scope of the original request by Senator Lamar Alexander. However, the limited focus of the report ignores two relevant ideas: the economic rationale for subsidies and their impact on the evolution of the electricity industry in the United States.
The EIA states federal subsidies to the energy sector more than doubled from 1999 to 2007. Domestic energy production however, barely increased. The report also concludes renewable technologies receive more assistance relative to technologies such as coal, natural gas, and petroleum on a per kilowatt-hour (kWh) basis. The limited scope and the methodology the EIA uses to frame its findings may force readers to conclude the production is not increasing because the government excessively subsidizes renewable technologies, which generate fewer kWh per subsidy dollar. However, this comparison is misrepresentative for a number of reasons.
This report argues the federal government's incentives have done little to increase overall energy production because the government focuses the majority of its subsidies on mature technologies while it should allot the majority of its incentives to nascent technologies. To illustrate this point, holes in the EIA's analyses will be exposed and alternatives to the agency's analyses will be presented. The main explanations are as such:
First, a subsidy, if at all justifiable, should be used to assist new, beneficial technologies accelerate to commercialization and self-sufficiency. In theory, all mature technologies should be free of subsidies and governmental support. This report examines historical levels of installed capacity and electricity output to confirm that coal, nuclear, petroleum, hydroelectricity, and natural gas are mature technologies while other renewable technologies, such as wind and solar are less mature. Given this segregation, technologies like coal and nuclear should receive fewer subsidies than renewable technologies. However, according to the EIA, subsidies from the federal government to the coal industry (not including refined coal) are 68 times greater than subsidies to the nascent industries like solar and geothermal, and subsidies to the nuclear industry are 90 times greater.
Second, subsidies and other incentives do not make an immediate impact. The EIA compares 2007 subsidies across technologies by measuring the dollars of federal support per kilowatt-hour produced in 2007. However, subsidies allotted in 2007 may take several years to increase production. Therefore, any production increases in 2007 may be the result of previous years' subsidies. To improve upon this, this report examines EIA subsidy data from 1999 and 2007 and devises a new and more relevant metric.
Also, energy consumption increased by 4.6% from 1999-2007, while production only increased by 0.1%, according to EIA data. With domestic energy consumption increasing at a faster rate than domestic energy production, the US will either face energy shortages or be forced to increase its reliance on foreign imports. Because the government does not have unlimited resources to support this growth in energy production, it must implement policy wisely to provide the best return per subsidy dollar. To achieve this goal, the government must allocate money to high growth nascent technologies. On other hand, mature technologies that have reached a plateau require large sums of money for minimal growth. This report presents data that demonstrates the large fiscal cost to grow mature technologies in comparison to younger technologies. For example, the government is spending approximately $3,200 million for every 1% growth in coal electricity production and $2,500 million per 1% growth in nuclear electricity production, while only spending $5.5 million per 1% growth in solar electricity production.
Finally, federal assistance is only one relevant issue. Legislators, academics, and businesspersons seeking to compare incentives and subsidies across technologies must attempt to quantify other factors to reach a valid comparison. This report, like the EIA report, will exclude state and local subsidies because of inherent difficulties with examining such data. It will also ignore any environmental and other benefits from subsidizing clean technologies
THE ARGUMENT FOR SUBSIDIES AND INFANT INDUSTRIES
To fully evaluate the efficacy of the federal subsidies to the energy sector, it is important to understand the economic theory behind subsidies and their intended purpose. This section will analyze the economic reasoning behind subsidies and the idea of infant industries, as it relates to different energy technologies within the United States.
A classical definition of a subsidy is a form of financial assistance either to a business or industry within an economic sector, which without the financial assistance, the business or industry would otherwise fail or not occur. While differing opinions regarding subsidies exist, many economists and academics believe the existence of subsidies helps the development and maturation process. Koplow describes the benefits of energy subsidies specifically.
"Justifications for energy subsidies include social welfare, protection and promotion of jobs or industries, rural development, and energy security."(Koplow, 2004)
Included with these benefits, this report argues that subsidies, when implemented properly, assist certain immature, or infant, industries in order to make them more competitive amongst their peers. Regarding infant industry states, Baldwin summarizes the economic theory behind state intervention in said industries:
"The essential point stressed by infant-industry proponents since Hamilton (1791) and List (1856) first wrote on the subject is that production costs for newly established industries within a country are likely to be initially higher than for well-established foreign producers of the same line, who have greater experience and higher skill levels."
(Baldwin,1969)
While Baldwin compares the competitive environment betweens firms located in different countries, the environment is analogous to those competing within domestic industries. The key factor is the infant or mature stage of each firm. Baldwin goes on to explain why this factor is essential:
"…Over a period of time new producers become 'educated to the level of those with whom the processes are traditional' (Mill, 1909,); and their cost curves decline."
The infant industry argument states that at a certain point government intervention is necessary and Baldwin proposes that immature industries are in the greatest need of state intervention. While Baldwin's paper criticizes the effectiveness of infant industry protection even he concedes the strength of the economic theory behind it:
"I will not deny that there are unique factors affecting new industries which may require market intervention by public authorities if a socially efficient allocation of resources is to be achieved."
While the industries this report considers infant are not necessarily "new" when compared to other technologies, these industries should be treated as such. For example, Thomas Cochran of the Pew Center on Global Climate Change writes of nuclear subsidies:
"These proposed subsidies are unjustified in my view, promoting both negative economic and environmental consequences relative to more benign renewable energy generating technologies. Moreover, nuclear power is a mature industry that has already benefited from tens of billions of dollars in government subsidies over many decades and should sink or swim of its own accord without additional taxpayer assistance." (Cochran, 2004)
Cochran takes this idea further writing:
"Since most existing nuclear plants are economically competitive with fossil-fueled plants in terms of forward costs, energy generating companies will continue to extend the licenses and operate the existing U.S. fleet of nuclear plants over the next several decades."
Essentially, Cochran believes nuclear and fossil-fuel plants are currently mature and economically competitive. Additionally, he proposes that any federal subsidies to these plants would not create new facility production and therefore no new growth because energy generators will use existing plant capacity for a long time to come.
Cochran's statements will be supported further by our analysis; however, the message is apparent. At certain points in an industry's maturation process the additional inflow of cash has little or no effect on its growth. Koplow supports Cochran's statements when discussing oil and gas subsidies:
"The fiscal cost of these subsidies is evident, especially in sectors such as oil and gas where historically high prices alone should provide sufficient incentives for expanded production."
Cochran also argues it may even be irresponsible to commit large subsidies to those energy technologies where the environmental consequences are much greater than the more benign alternatives. Again, Koplow supports Cochran's statements. "Indications are that, as we extract more dilute, deeper, and dirtier energy sources, the energy subsidy required to extract and upgrade the new sources increases."
It is clear given the existing academic evidence, that the arguments behind subsidies are strong. As a form of financial assistance to a business or industry, a subsidy can help expedite growth. However, a subsidy best achieves this from the infant stage and has diminishing returns towards a more mature stage. Building on Cochran's argument, this report will empirically illustrate a disproportionate amount of subsidies is allotted to mature domestic energy technologies, rather than more infant technologies that would receive greater benefit from the subsidy cash inflow.
DEVELOPMENT OF THE TECHNOLOGIES
In order to differentiate between nascent and mature industries, this report tracks the development of different technologies over the past century using two methods. The first method examines the name plate installed capacity of each power generator in terms of megawatts (MW) and aggregates them over time. The second approach tracks the yearly output of each technology in terms of kilowatt-hours (kWh) and compares them along their life-cycles. Individually, the methodologies have their own idiosyncrasies which prevent one hundred percent accuracy. The problems with each methodology will be discussed in further detail below. However, when viewed together, the installed capacity and electricity generation output methods provide an accurate picture of the size of each respective market. This report uses EIA data to track each technology over a set timeframe.
Method 1: Tracking Industry Growth by Installed Capacity
The first method measures the maturity of different energy technologies by graphing the cumulative installed capacity of each technology over a given timeline. However, comparing different energy technologies by their respective levels of installed capacity does have pitfalls, as described below.
When a power plant is installed, it must register the name plate or installed capacity of production. These ratings are a measurement of power and are often rated to the largest power output that can be produced under an optimal situation. It must be noted however, that ten 20 MW solar power plants do not produce the same amount of electricity as a 200 MW coal fired power plant.
Coal power plants only produce 70% of the potential electricity output (known as capacity factor) over the course of a year due to a number of factors such as maintenance, spinning reserves, or limited demand. Solar is inherently different in that the sun is exposed for a set period of time each day and the intensity of the available sunlight varies during the day. Also, the solar potential in the southwestern part of the United States with greater sun exposure is significantly greater than the solar potential of those areas with less exposure. Of the projects that were listed in the EPA's Emission & Generation Resource Integrated Database (eGrid), the average solar installation has a capacity factor of 20%. (EPA, 2008) To put this in perspective, we would need 700 MW of solar installation to roughly equal the output of a 200 MW coal power plant. However, capacity factors are not the same as efficiency nor should they be used to compare if one technology is "better" than another.
Capacity factors are important solely for the purpose of understanding how different nameplate capacity ratings vary from each other. This report does not directly use the capacity factor during the analysis because this data will be stress-tested when compared to a second method that tracks net electricity generation.
Exhibit 1 below looks at the cumulative installed nameplate capacity for different technologies in the United States, from 1915 till 2006. The 2007 data is not included in this report since it has yet to be published. At first glance, three major trends are apparent in this chart. First, natural gas and coal are the two most prevalent technologies to date, having over 75% of the cumulative installed capacity.
Second, many technologies appear to have plateaued beginning in 1990 and show little or no added capacity in the last fifteen years. These technologies include coal, nuclear, hydro power, and fuel oil (diesel, etc). Only natural gas and wind appear to be adding capacity in any significant manner in the last five years.
Third, most of the technologies have been in existence for over 40 years, with the majority of the technologies growing significantly between 1955 and 1985. To better evaluate how and when each technology gained a significant foothold in the market place, the y-axis (installed capacity) scale was adjusted by a factor of 10.
Exhibit 1: Cumulative Installed Capacity in U.S. from 1915 to 2006
Exhibit 2 below focuses on the growth period of each technology by changing the y-axis scale and observing data between zero and 50,000 MW installed capacity. This is the same graph as in Exhibit 1 on a different scale.
The capacities of hydroelectric power, coal, natural gas, nuclear, and to lesser extent fuel oil drastically increased between 1915 and 1975. Wind power is also notable since it is just beginning to experience the same exponential growth as it begins to gain a foothold in the market place. Solar, geothermal, and biomass have yet to experience the rapid growth other technologies experienced in earlier years.
Exhibit 2: Cumulative Installed Capacity in U.S. from 1915 – 2006, altered y-axis
Method 2: Electricity generation
The second method for categorizing each technology measures the respective output in terms of kilowatt-hours (kWh). This method negates the problem of determining a capacity factor for each technology as previously discussed. It is advantageous because it only measures the output of each technology and attempts to standardize it across the industry.
The major drawback of tracking actual electricity generation is that many power plants have a useful life of thirty to forty years. This means a natural gas plant installed in 1955 would no longer be in commission and subsequently omitted from this study. This omission would favor older technologies since any omission of previous generation would make the older technology appear newer in their overall lifecycle.
In Exhibit 3, the graph shows that coal provides the majority of the electricity generated in the United States. It has been in production for over 60 years and due to a plethora of domestic sources, this technology serves as a base load in most areas; nuclear also serves as a base load for power generation. However over the past 10 years, the overall output from nuclear power has plateaued. As seen earlier in Exhibit 1, natural gas has the largest installed capacity. Now, however, we observe that natural gas provides less than half of the electricity generated by coal power plants. This difference exists because a majority of natural gas plants were built as peaking power plants. These plants generally operate only during times of high demand. As well, the exhibit illustrates that hydroelectric power and petroleum have decreased from their previous peaks. Once again, wind and solar only make up a small portion of electricity generation, but these technologies are 35 to 40 years younger than their counterparts.
Exhibit 3: Net Electricity Generation from 1949 - 2006
Exhibit 4 below provides a more focused look at the net power generation of each technology during the first couple of decades they were in operation. Three areas specifically, should be looked at in greater detail.
First, petroleum generators have been used for power generation since before 1949, but their acceptance into the market place appears to be staggered. Between 1949 and 1964, there are numerous peaks and troughs in the growth of the technology before it became commercially viable. More notably, the technology is in rapid decline from 1979 until now.
Second, wind power is just beginning to reach commercial viability and its trajectory is similar to nuclear in 1970.
Third, solar and geothermal energy are still nascent technologies and must be given the correct economic stimulus to push them towards commercial viability.
Exhibit 4: Net Electricity Generation from 1949 -2006, altered y-axis
Based on the information from the nameplate installed capacity and the net electricity generation, we are able to identify coal, nuclear, hydroelectric, natural gas, and petroleum as mature technologies. However, natural gas continues to expand in terms of installed capacity because of the positive economics for peaking power electricity production. It is also clear that wind is at a critical point in the lifecycle and close to full commercialization as long as it receives proper incentives. Lastly, solar, biomass, and geothermal technologies are still nascent and need further incentives to reach commercial acceptance.
ANALYSIS AND COMPARISON
The report discusses earlier that subsidies should help infant industries reach maturity, and mature industries no longer need as much support as immature industries. The report also specifies coal, nuclear, hydroelectric, natural gas, and petroleum as mature technologies and wind, solar, geothermal, and biomass as nascent technologies. In theory, coal, nuclear, hydroelectric, natural gas, and petroleum should receive fewer subsidy dollars than solar, geothermal, and biomass. Exhibit 5, reproduced below from the EIA report, shows this is not the case.
According to Exhibit 5, subsidies from the federal government to the coal industry (not including refined coal) are 68 times greater than subsidies to the nascent industries like solar and geothermal, and subsidies to the nuclear industry are 90 times greater. This mix does not seem to meet the objective of using subsidies to help grow nascent industries, as nascent industries like solar, geothermal, and biomass receive tiny amounts of subsidies compared to mature technologies like nuclear and coal. In fact, all renewables combined, including hydroelectric and wind, receive fewer subsidies than nuclear and half the subsidy dollars of refined coal.
The federal government is not using tax dollars wisely because it is sending more incentives to mature technologies than to nascent technologies. In fact, the EIA report states that federal subsidies to the energy industry doubled while production remained unchanged between 1999 and 2007. According to the EIA's data, these subsidies increased 102.4% over that time period, and production increased by less than 0.1%.
This disconnect between subsidies and production is a problem especially because energy consumption increased by 4 quadrillion Btus, or 4.6%, from 1999-2007. With domestic energy consumption increasing faster than domestic energy production, the US will either face energy shortages or be forced to increase its reliance on foreign imports. If the federal government is seeking to decrease reliance on foreign imports while meeting domestic energy needs, it needs to devise an incentive strategy that effectively employs its budget to increase energy production.
An issue with assessing which strategy is best aligned to meet the country's energy needs is how to measure the cost effectiveness of prior strategies and forecast the cost effectiveness of new strategies. This portion of the report will analyze two different arguments about the government's incentive strategy. Statistics from the EIA report imply subsidizing nascent renewable technologies is costly. This report poses a counter argument to the EIA's premise by showing the cost of growing mature technologies to meet US energy needs is higher than the cost of growing nascent technologies, and the federal government would use tax dollars more effectively by subsidizing these nascent energy technologies.
Analysis of EIA Table
The EIA attempts to measure the cost effectiveness of prior strategies in one of its central tables that compares subsidies per unit of electricity production.
This EIA table, found in the executive summary of the EIA report and reproduced below, implies subsidizing wind and solar is more expensive than subsidizing most other technologies on a per kWh basis. But the main problem with this table, which the EIA does recognize, is it assumes subsidies in 2007 directly translate into production in 2007. We previously argued the point of subsidies is to help grow nascent industries and not to make an immediate positive impact on the industry of the government's choice. Technologies like coal, petroleum, and nuclear have such low subsidies per unit of production because these technologies are mature and have high net generation values after benefiting from years of incentives. Natural gas's growth has not slowed like other mature technologies including coal, nuclear, and oil, but has achieved a solid foothold in the market. Therefore, it no longer requires as many incentives. Wind and solar are still in the infant stage relative to other technologies and therefore these technologies look very expensive per unit of production.
Exhibit 5: Reproduction of Table ES5 in EIA Report
Alternative Analyses of EIA Data
To better assess the cost effectiveness of the federal government's incentive strategies, we created a new metric that compares subsidy levels to the production growth rates of each energy technology. Specifically, the calculation is:
Subsidy and support in USD ÷ Compound annual growth rate
However, the metric we have devised is not without flaws similar to the metric the EIA uses. The inherent problem is subsidy data is only available in snapshots and cannot be compared over a series of years. However, this new metric provides a better representation of how effectively the government has used its subsidy budget, and more importantly, how it should allocate the budget in the future.
We used data from the EIA incentive report as our measure of federal subsidies and assumed the incentives in 1999 and 2007 were representative of a typical year. We used EIA databases to measure production growth rates for each energy technology from 1999-2007. We used this time frame because of data limitations and because we wanted growth rates to partially reflect the effect of 1999 subsidies while providing an idea of how production will grow moving forward.
Comparing the levels of subsidies in terms of dollars to the growth in production levels gives an idea of how much money the government spends to grow energy production and capacity. For example, in 1999, the federal government spent $740 million on subsidies and incentives to nuclear energy. Energy generation from nuclear plants grew by an annual rate of 1.26% from 1999-2007, so the federal government is spending $553 million ($740 million / 1.26%) to increase energy production from nuclear plants by 1% annually, based on the 1999 snapshot.
The tables below display this metric for all energy production and incentives in 1999 and 2007, and for electricity production and incentives in 2007. Reliable information on subsidies to electricity is not available for 1999.
1999 Energy Subsidies
Exhibit 6: Subsidies to Energy ($ millions) in 1999 vs. 1999-2007 Annual Growth in Production
In this table above, which looks at energy subsidies and energy production, not just electricity subsidies and electricity production, coal looks relatively expensive compared to most other technologies. According to the 1999 numbers, the government is spending $5.7 billion for every 1% growth in coal production. It has spent billions of dollars on natural gas and petroleum, which the EIA lumps into one category, only to achieve negative growth. Because this table represents total energy production, petroleum, which has been experiencing negative production growth, is more heavily weighted than natural gas, which has been growing more rapidly than most energy technologies.
Renewables without hydro included are much less expensive, at only $370 million per 1% growth in production. Subsidies to nuclear are between coal and non-hydro renewables at $585 million per 1% production growth.
2007 Energy Subsidies
Exhibit 7: Subsidies to Energy ($ millions) in 2007 vs. 2002-2007 Annual Growth in Production
The 2007 data tells a story similar to the 1999 data. Coal is again the most expensive at $5 billion per 1% production growth, and natural gas & petroleum production growth was negative from 2002-2007. Nuclear production was less expensive to grow than coal, receiving $1.9 billion for every 1% growth in production, but more expensive than non-hydro renewables, which received just $622 million per 1% growth.
2007 Electricity Subsidies
Exhibit 8: Subsidies to Electricity ($ millions) in 2007 vs. 2002-2007 Annual Growth in Production and Capacity
(6) Time series production and capacity data for refined coal not available
Unfortunately the EIA did not separate electricity subsidies from energy subsidies in their 1999 report, so we only have the 2007 data. Even so, this set of data provides another interesting view on how wisely the federal government is spending its money.
According to the data from the EIA, the government is spending $3.2 billion for every 1% growth in coal electricity production and $2.5 billion for every 1% growth in nuclear production. At the other end of the spectrum are natural gas at $64 million and various renewables at $47 million and below. Solar is the least expensive, at $5.5 million per 1% production growth.
The capacity statistics are similar. Coal capacity is decreasing, despite receiving $3 billion in subsidies, and the government is spending $3.3 billion for every 1% growth in nuclear capacity. Solar is again the lowest, receiving only $3.1 million in subsidies for every 1% growth in capacity.
It is not fair to say the government needs to spend $3.2 billion to increase coal production by 1% and only $5.5 million to increase solar production by 1%. The 2007 subsidies will not necessarily lead to the same growth rates each technology experienced from 2002-2007.
However, it is apparent from the data that the government is using its money more effectively when subsidizing nascent technologies instead of mature technologies. Earlier in the paper, we stated the mature technologies are coal, petroleum, nuclear, hydro, and to a lesser extent, natural gas. Each of these technologies is more 'expensive' to subsidize than the nascent renewable technologies. In fact, when looking at broader categories, the government is spending $1.5 billion for every 1% growth in fossil fuel production, $2.5 billion for every 1% growth in nuclear, and $174 million for negative growth in hydro. Meanwhile, the government only spent $148 million for every 1% growth in non-hydro renewables.
One argument to the analysis above may be that it is not fair to compare 2002-2007 growth to 2007 subsidy levels. We agree to an extent, although we do believe recent growth is as good of an indicator of future growth as any other predictor. However, comparing 2007 subsidies to the EIA's production forecasts, done in the table below, does not change the story. Mature technologies still appear to be more expensive to subsidize than nascent technologies. Nuclear costs almost $10 billion per 1% production growth, while renewables only cost $266 million.
Exhibit 9: Subsidies to Electricity ($ millions) in 2007 vs. 2008-2015 Annual Growth in Production and Capacity
(7) Time series production and capacity data for refined coal not available
The table above shows that the US needs over 500 TWh of additional electricity production to come on line in the next eight years. The government will most likely play a large role in helping the energy industry meet this demand. If this is the case, the government needs to focus on the most cost effective subsidies, especially with its strained budget. The federal government needs to spend money on high growth nascent technologies, not mature technologies that have reached a plateau and require huge amounts of money to grow. Expanding subsidies to mature industries just does not make sense.
Conclusion
If the goal of the government is to incentivize the investment necessary to create additional electricity capacity and simultaneously reduce the country's reliance on energy imports, it will need to further examine the cost effectiveness of its energy strategy. Currently, the government inefficiently uses tax dollars by subsidizing mature technologies rather than supporting more nascent technologies. This report shows that coal, petroleum, nuclear, hydro, and natural gas have reached commercial viability, while solar, wind, geothermal, biomass, and a number of other new technologies have yet to reach this threshold, and that the former technologies currently receive greater cash inflows. However, according to the new metric discussed, the government spends $1.5 billion per 1% growth of fossil fuel generation, $2.5 billion for every 1% growth in nuclear and only $148 million for every 1% growth in renewable technologies (excluding hydro). Therefore, given these growth comparisons the government must expend on high growth nascent technologies. Because these technologies have greater growth potential per subsidy dollar as opposed to their counterpart, tax dollars would most efficiently be spent on these industries. If the government is determined to use subsidies as a strategic investment, it must focus more on technology growth rates over time rather than subsidy dollar per output of each technology.
REFERENCES
Baldwin, R. E., "The Case against Infant-Industry Tariff Protection", The Journal of Political
Economy, Vol. 77, No. 3 (May – Jun., 1969), pp. 295-305
Cochran, T. B., "Critique of 'The Future of Nuclear Power: An Interdisciplinary MIT Study'", "The
10-50 Solution: Technologies and Policies for a Low-Carbon Future", The Pew Center on Global Climate Change and the National Commission on Energy Policy
Environmental Protection Agency (EPA). (2008). The Emissions & Generation Resource Integrated
Database (eGrid) [Data file]. Retrieved from http://www.epa.gov/cleanenergy/energy-resources/egrid/index.html
Gilliland, M. W., "Energy Analysis and Public Policy", Science, New Series, Vol. 189, No. 4208 (Sep.
26, 1975), pp. 1051-1056
Koplow, D., "Subsidies in the US Energy Sector: Magnitude, Causes, and Options for Reform", Earth
Track, Inc., (Cambridge, MA), November 2006, www.earthtrack.net
EIA Statistics by subject:
Historical electricity generation statistics
Energy Information Administration, Annual Energy Review 2007. Table 8.2a & b Net Generation: Total (All Sectors), 1949-2007. [Data file]. Retrieved from http://www.eia.doe.gov/emeu/aer/elect.html .
Historical electricity capacity statistics
Energy Information Administration, Annual Energy Review 2007. Table 8.11a Electric Net Summer Capacity: Total (All Sectors), 1949 – 2007 [Data file]. Retrieved from http://www.eia.doe.gov/emeu/aer/elect.html .
Historical energy production statistics
Energy Information Administration, Annual Energy Review 2007. Table 1.2 Primary Energy Production by Source, 1949 – 2007 [Data file]. Retrieved from http://www.eia.doe.gov/emeu/aer/overview.html .
Projections
Energy Information Administration, Annual Energy Review 2008. Table 8. Electricity Supply, Disposition, Prices, and Emissions [Data file]. Retrieved from http://www.eia.doe.gov/oiaf/aeo/graphic_data.html .
Renewable Generation Stats
Energy Information Administration, Renewable Energy Consumption and Electricity Preliminary Statistics, 2007. Table 3 Electricity Net Generation from Renewable Energy by Energy Use Sector and Energy Source, 2003-2007 [Data file].
Historical electricity capacity statistics
Energy Information Administration, Annual Energy Review 2007. Electricity Net Generation: Electric Power Sector, 1949-2007, [Data file]. Retrieved from http://www.eia.doe.gov/emeu/aer/elect.html .
Electricity Generating Units
Energy Information Administration. Existing Electric Generating Units in the Unites States, 2006 [Data file]. Retrieved from http://www.eia.doe.gov/cneaf/electricity/page/capacity/capacity.html.