Electric and steam generating plants are a significant source of sulfur dioxide (SO2) and nitrogen oxide (NOx) emissions. These emissions are the primary cause of acid rain (otherwise referred to as acid deposition). Acid rain is suspected of harming human health and is known to damage ecosystems and man-made materials. Acid rain also reduces visibility.

To control acid rain, an Acid Rain Program has been established under the Clean Air Act, as amended in 1990 (CAA). The control of acid rain under this program is to be accomplished in two phases: Phase I and Phase II. Phase I, which began in 1995, affects electric (mostly coal-burning) plants that are the largest emitters of SO2. Phase II will begin in the year 2000 and will affect a larger group of plants.

The purpose of the Acid Rain Program is to reduce the adverse effects of acid rain. The objectives of the program are achieved through a system of marketable allowances. These allowances are used by utility units to cover their SO2 emissions. One allowance means that an affected utility unit may emit up to one ton of SO2 during a given year. Utilities cannot emit more tons of SO2 than they hold in allowances. Allowances may be bought, sold, or traded, and any allowances that are not used in a given year may be banked and used in the future.

Does the Acid Rain Program Apply to Your Community?

Yes, if your community operates a municipal power plant that has been identified by EPA as a source of SO2 emissions that is or will be targeted under either Phase I and Phase II of the Acid Rain Program. EPA maintains a list of affected plants in the Code of Federal Regulations (CFR) at 40 CFR section 73.10.

Generally speaking, the Acid Rain Program affects utility units that began commercial operation before November 15, 1990 and serve a generator with an input capacity of 25 megawatts of electricity (MWe) or greater. These units are referred to as existing units. In addition, almost all new units, i.e., those that began commercial operation on or after November 15, 1990, are subject to the acid rain regulations.

In some cases, a utility unit may be eligible for an exemption from some of the acid rain requirements. For example, if a utility unit is a new unit and serves generators with total input capacity of 25 MWe or less, and it burns clean fuels, an exemption may be possible. You must apply to EPA to determine if your unit may be eligible for an exemption.

Actions Your Community Should Be Taking

Owners or operators of plants may, at their option, request EPA to determine if they will be affected by the Acid Rain Program. This is called applying for an Applicability Determination. Applying for an Applicability Determination is not mandatory.

A utility unit that is affected by the acid rain regulations must measure and record its emissions of SO2, NO2, and carbon dioxide to ensure compliance with the emissions limitations that have been established by the allowances held by that utility unit.

Affected sources must file a permit application and compliance plan for each affected unit with the permitting authority. The permitting authority will be either an approved state permitting authority or EPA.

Even if your plant is exempt from the acid rain regulations, it may still be possible to participate in the Acid Rain Program. Plants that wish to participate may opt-in to the program. Plants that opt-in may, with certain restrictions, be given emissions allowances that they can sell to other units.

Timetable

Phase I plants were required to comply with the acid rain regulations beginning on January 1, 1995. Plants affected by Phase II of the Acid Rain Program will be required to comply beginning on January 1, 2000.

Additional Information

The regulations for the Acid Rain Program can be found in the Code of Federal Regulations beginning at 40 CFR part 72.

For additional information about the Acid Rain Program and how the acid rain regulations may affect your plant, contact the appropriate EPA regional and state offices.

For general information about the Acid Rain Program, contact the Acid Rain Hotline. Telephone: 202/233-9620.