# Presentation: 515314

## The Acid Rain Experience:  Should We Be Concerned about SO2 Emissions Hotspots?

- Emissions Marketing Association Annual Spring Meeting
- Amy Kinner, Rona Birnbaum
- May 4, 2004

## What Are the Benefits of a Cap and Trade Approach?

- Certainty that a specific **regional** level of emissions will be achieved and maintained over time (even with economic growth)
- More regulatory certainty, more compliance flexibility, and lower transaction costs for sources
- Fewer administrative resources needed by industry and government
- Drives down costs, making further improvements feasible
- Complements other Clean Air Act provisions (e.g., NAAQS) to help protect local air quality

## National SO2 Emissions Have Been Reduced Significantly

**National SO2 Emissions Have Been Reduced Significantly**

- 	Total annual emissions from Acid Rain sources were reduced by an average of approximately 5 million tons between 1990 and Phase II (2000-2002).

- Total Annual SO2 Emissions From Acid Rain Sources (1980-2002)

## State-Level SO2 Emissions Were Reduced in States with Highest 1990 Emissions 

**SO****2**** Emissions from Power Plants**
**1990-2002**

- Greatest emissions reductions in states with highest emissions in 1990.
- Largest reductions in Ohio, Indiana, Missouri, Illinois, and West Virginia.

## What Have People Been Saying about Emissions Reductions under the Acid Rain Program?

_**The Acid Rain Program Reduced Emissions at Highest **_
_**Emitting Sources:**_
- In Phase I, highest-emitting sources reduced the most.
- (Environmental Law Institute, 2000 and Environmental Defense, 2000).
- In Phase II, most abatement by units with higher SO2 emissions, especially in the Midwest.
- (Ellerman, 2003)
_**Increases in SO**__**2**_ _**Emissions Occurred during the Acid **_
_**Rain Program:**_
- SO2 emissions in 16 states increased from 1990 levels.
- (Environmental Integrity Project, 2002).
- Between 1995 and 2000, SO2 emissions increased at 300 of the “dirtiest” 500 power plants
- (Clear the Air, 2002).

**Our analysis describes how annual SO2 emissions changed between 1990 and 2000-2002 (Phase II)**
**Why is EPA assessing the program now?**
- All good environmental programs should track results for accountability.
- There are requirements to assess impacts (e.g., GPRA/PART, NAPAP).
- Several years of Phase II data are now available.

## How Could We Identify Acid Rain Program Sources that Could Contribute to Local Impacts?

**	****There are various ways we could identify sources that could potentially be of concern.**
- 	_Emissions_
- Plants with high emissions (e.g., highest 25% of emitters).
- Plants that increased emissions or did not reduce as much as others during the program.
- Plants that did not improve their SO2 emissions rates during the program.
- States or regions where emissions are high or increasing.
- 	_Air Quality/Environmental Effects_
- Plants affecting air quality in an area where pollutant levels are high (e.g., non-attainment area).
- Plants affecting air quality in a “sensitive” area (e.g., high numbers of asthmatic children or nitrogen-saturated forests).

**	**

**	****The Acid Rain Program accomplished its goal of reducing national SO2 emissions. **
**	****What happened at the local level?**

## National Annual SO2 Emissions Were Reduced by 32% Between 1990 and 2000-02

**National Annual SO****2**** Emissions Were Reduced by 32% Between 1990 and 2000-02**

- * This only includes facilities with emissions in 1990.  It does not include new sources or sources that did not operate in 1990.

**SO2 Emissions Changes Between 1990 and 2000-02**
**(Acid Rain Sources)**

- 335 facilities _decreased_ emissions between 1990 and 2000-02 (total reductions = 6.3 million tons).
- 282 facilities _increased_ emissions between 1990 and 2000-02 (total increases = 1.2 million tons).*

**Blue circles indicate sources that reduced emissions more than 1,000 tons.**
**Orange squares indicate sources that increased emissions more than 1,000 tons.**
**The size of the symbols are proportional to the size of the change in emissions.**
**Emissions from sources represented by hollow circles did not change more than 1,000 tons.**

## Largest Reductions Occurred at Plants with Highest 1990 Emissions

**Plant-Level 1990 SO2 Emissions and SO2 Emissions Changes by 2000-02**

- Plants with highest emissions in 1990 achieved greatest reductions by 2000-02.
- Plants that increased emissions tended to have lower emissions in 1990.
- Many plants that _decreased_ emissions experienced substantial decreases, while most plants that _increased_ emissions experienced smaller increases.

## A Comparison of Third Quartile and Fourth Quartile Plants*

**A Comparison of Third Quartile and Fourth Quartile Plants***

- 44% of plants reduced emissions.
- Average SO2 rates improved only slightly.
- Large percent increase in heat input (30%).

**Are third quartile plants now a concern?**
- While many increased emissions, 72% improved their SO2 rates.
- Third quartile plants continued to have lower average emissions and SO2 rates than fourth quartile plants.

- 74% of plants reduced emissions.
- Large average improvements in SO2 rates.
- Smaller percent increase in heat input (16%)

- *  Plants were ranked by 1990 emissions (1=lowest emissions, 627=highest emissions).  Using these rankings, plants were divided into quartiles, with plants with the highest 25% of emissions in the fourth quartile and plants with the next highest 25% of emissions in the third quartile.

## Plants in Fourth Quartile of Emissions in 1990: A Comparison of Plants that Increased and Plants that Decreased Emissions

- Of the 157 plants with the highest emissions in 1990 (fourth quartile), 40 plants increased emissions, while 117 plants decreased emissions._** **_
- Plants that _decreased_ emissions during the Program had *higher* mean emissions and higher SO2 rates in 1990.
- Plants that _increased_ emissions from 1990 levels had *higher* mean emissions and higher mean SO2 rates by 2000-02.

## Under the Acid Rain Program, National SO2 Reductions Were Achieved Despite Significant Increases in Heat Input

- National heat input increased by 20% between 1990 and 2000-02, including increases in heat input of:
- 35% at facilities that increased their emissions
- 9% at facilities that decreased their emissions
- If SO2 rates had not improved, national SO2 emissions would have increased by 20%.
- _Actual_ 2000-02 emissions (at both increasing and decreasing facilities) were below what they would have been had 1990 SO2 rates not improved.

## Regional Sulfate Concentrations Have Been Reduced

**Regional Sulfate Concentrations Have Been Reduced**

**Average Annual Sulfate Concentrations**
**(1989-91)**

**Average Annual Sulfate **
**Concentrations**
**(2000-02)**

**Source: Clean Air Status and Trends Network (CASTNET)**

- The Acid Rain Program has achieved its main goal, reducing regional sulfur deposition and sulfate concentrations significantly.  This has provided substantial benefits to human health and the environment.

## Has the Program Improved Air Quality Overall?

**Source:  EPA, Latest Findings on Air Quality: 2002 Status and Trends Report. (August 2003)**

- During the Acid Rain Program, other protections (NAAQS) were in place to protect local areas.
- Average SO2 concentrations have dropped steadily
- Average SO2 concentrations remain well below the NAAQS.

## Conclusions

- The Acid Rain Program accomplished its main goal of achieving large regional reductions in emissions and reducing regional sulfur deposition and sulfate concentrations significantly.
- This has provided substantial human health and environmental benefits.
- While many of the largest plants decreased emissions, some increases in emissions were also observed, often due to increased unit usage (growth).
- EPA will continue to look at local air quality to understand the local environmental and health impacts of such increases in emissions.
- If such increases in emissions are a problem, protection of local environments in the future will rely on:
- National health-based standards and state/local government authority to address local impacts
- Tighter cap (e.g., proposed in Clean Air Interstate Rule)