Scrubber Retrofits at Existing Coal Plants

SO2 Pollution and Pollution Controls
In 1970, the U.S. Congress passed the Clean Air Act, which regulated the emission of sulfur dioxide (SO2), among other forms of pollution. SO2 contributes strongly to acid rain, and causes or exacerbates respiratory illnesses. However, the legislation allowed for exemptions for older power plants. This legislation has been strengthened since then: in 1977, the New Source Review increased compliance by states, while the EPA's Clean Air Interstate Rule, passed in 2005, requires a 57% cut in U.S. SO2 emissions by 2015. (Roughly 60% of U.S. SO2 emissions come from coal-fired power plants.) Especially since 2005, many utilities have begun attaching SO2 scrubbers to their coal-fired generating stations. However, many plants still do not have adequate - or even any - SO2 controls.

According to data from the Energy Information Administration, the following proportions of coal-fired power plants with capacity over 100 MW had SO2 scrubbers in 2005:

It is possible that some coal-fired plants with SO2 scrubbers did not report their scrubbers to the EIA, and thus that the above table overstates the number of plants without SO2 controls. However, out of 257 U.S. coal-fired power plants which produced more than 2,000 GWh of power in 2006, 86 had SO2 emissions that were higher than 10 lb/MWh – compared with an average of 1 lb/MWh for coal plants with state-of-the-art SO2 scrubbers. We can surmise that these 86 plants almost certainly have zero or extremely minimal SO2 scrubbers, or have SO2 scrubbers that were not functioning in 2006.

A more recent survey (June 2008) of coal-fired power plants conducted by the Environmental Protection Agency found that 209,000 MW out of 329,000 MW of capacity, or 63.5%, had no scrubbers. Of the 120,000 MW fitted with scrubbers, 104,000 MW represented wet fluidized gas disposal systems and 16,200 MW represented dry fluidized gas disposal systems.

The following table summarizes the findings of the EPA survey (June 2008):

In 2008, the Environmental Protection Agency released projections about future scrubber systems at coal-fired power plants. The following table shows the EPA's projections for scrubbers in 2009 and 2010. The reason that the total capacity represented by these figures is lower than the figures shown above (316,000 MW in 2009 and 318,000 MW in 2010, compared to the 329,000 MW shown above for of capacity survey in 2008), is that these figures are based on a database that uses summer and winter capacity rather than nameplate capacity.

The following table summarizes the data from EPA's 2008 survey and 2009/2010 projections:

Estimated scrubber retrofits resulting from the Clean Air Interstate Rule (CAIR)
The following list is based on the U.S. Environmental Protection Agency's (EPA) current draft estimates of announced sulfur dioxide (SO2) control technologies (i.e. scrubber) to be installed at coal plants as a result of the Clean Air Interstate Rule (CAIR), a review of trade press announcements of scrubber installations and discussions with individual States. This list was last updated in July of 2008. These operations and construction upgrades must be fully evaluated by the EPA and must also be considered in the context of recent court decisions.

Economic Study Supports Coal Plant Phase-Outs Over Retrofits
In March of 2010 Natural Capitalism Solutions, an environmental advocacy group based in Longmont, Colorado, released a report that favored phasing out existing coal plants over retrofitting them with scrubber technology. The report titled, “Coal Plants in Transition: An Economic Case Study,” provided a “proof of concept” for utilities to consider as they evaluate investments in new generation capacity and upgrades to existing facilities.

“We are quickly entering a water- and carbon-constrained world, and we wanted to look at what options might be available to utility managers and other energy providers,” said Paul Sheldon, a senior consultant at Natural Capitalism Solutions and the report’s main author. “We believe that these findings represent a business approach for energy managers to consider as they are faced with difficult decisions regarding the future of their facilities. We’ve shown that this approach allows them to maintain reliability and still profit in their transition to 21st century energy technologies.”

Using the 35-year old, 2,250-megawatt Navajo Generating Station near Page, Ariz. as a case study, the group's analysis examined the costs and benefits of the plant’s future. As with many aging power plants nationwide, Navajo is due for upgrades necessary for it to comply with the EPA's pollution and air quality regulations. The report notes that retrofits can entail substantial costs, running into the hundreds of millions of dollars.

The report states that such facilities, in order to protect jobs and move in a more environmentally safe direction, will be more profitable by abandoning retrofit plans and instead embracing a full range of clean energy resources, including wind, photovoltaic and concentrated solar, geothermal, and biomass, combined with large-scale supply and demand- side efficiency measures.

Related SourceWatch articles

 * Air pollution from coal-fired power plants
 * Campus coal plants
 * Clean Air Act
 * Clean Air Interstate Rule
 * Clean Air Watch
 * Clean Coal Technology
 * Clear Skies Initiative
 * climate change / global warming
 * Climate impacts of coal plants
 * Coal
 * Coal and jobs in the United States
 * Coal-fired power plant capacity and generation
 * Coal moratorium
 * Coal phase-out
 * Coal plant conversion projects
 * Coal plants near residential areas
 * Coal Studies
 * Coal waste
 * Comparative electrical generation costs
 * Dispelling the myths of the acid rain story
 * Divestment and shareholder action on coal
 * Environmental impacts of coal
 * Environmental Protection Agency
 * EPA Coal Plant Settlements
 * Existing U.S. Coal Plants
 * Fly ash
 * Health effects of coal
 * Heavy metals and coal
 * Mercury and coal
 * New Source Review
 * Oldest existing coal plants
 * Opposition to existing coal plants
 * Particulates and coal
 * Radioactivity and coal
 * Retrofit vs. Phase-Out of Coal-Fired Power Plants
 * Sulfur dioxide and coal
 * Scrubbers
 * Sulfur dioxide and coal
 * Transport Rule
 * United States and coal

External resources

 * "Scrubbers under construction or planned for operation by 2010 at 100 top polluting power plants for SO2 by tons/yr," Environmental Integrity Project