Any operating stationary combustion source that emits sulfur dioxide (SO₂) but is not otherwise required to meet the mandatory SO₂ emissions limitations of Title IV is eligible to opt into the acid rain program. Combustion sources are defined as fossil fuel-fired boilers, turbines, or internal combustion engines. The opt-in program offers a combustion source a financial incentive to voluntarily reduce SO₂ emissions. By reducing emissions below allowance allocation, an opt-in source will have unused allowances which can be sold in the SO₂ allowance market. Opting in will be profitable if the revenue from the sale of allowances exceeds the combined cost of the emissions reduction and the cost of participating in the opt-in program. Further information on the opt-in program is available on the USEPA Air Markets web page.

Any source subject to the Phase II permit program will also be subject to the Cross-State Air Pollution Rule (CSAPR).

Phase II Acid Rain Permits' Interface with Renewable Operating Permits

All sources subject to the Title IV acid rain program are also required to obtain a Renewable Operating Permit (ROP). For new sources, the Title IV Phase II acid rain application is considered a temporary acid rain permit until the ROP and final acid rain permit are issued together. All of the applicable requirement conditions are included in the application. Through signature on this application by a designated representative or an alternate representative, the source agrees to follow these conditions until the acid rain permit is formally issued with the ROP.

Phase II Acid Rain permits expire in conjunction with the facility's ROP; and renewal applications must be submitted with the ROP renewal application. More information on the ROP program can be found through the AQD's ROP web pages.

When an acid rain permit is final, it is incorporated into the associated ROP. All ROPs can be found through the sorted lists for ROP public notice process permits (draft, proposed, and final).

History and Science of Acid Rain Program in Michigan

The 1990 amendments to the federal Clean Air Act included the Title IV "Acid Deposition Control" provisions. The federal regulations to implement the Title IV program include the provisions of Parts 72, 74, and 76 of Title 40 of the Code of Federal Regulations. Michigan has adopted the federal regulations by reference. AQD is the authority responsible for issuance of Phase II acid rain permits in Michigan.

The first Phase II acid rain permits for SO₂ requirements were issued in Michigan as of December 16, 1997. In accordance with the federal requirements, these Phase II acid rain permits for coal-fired facilities were reopened to add nitrogen oxide (NO_x) emission limits.

Acid rain permit applications for new units are required to be submitted 24 months before the unit commences operation. These acid rain permits are valid for a maximum of five years. The permit renewal applications and NO_x compliance plans (if applicable) are submitted at the same time as the associated Title V ROP renewal application. A copy of these applications should be sent to the appropriate AQD district office and also to Brian Carley at the address above.

All Title IV requirements are incorporated as an appendix (generally Appendix 9) of the ROP. For the new or renewal Phase II acid rain permits, the requirements are incorporated into the ROP upon issuance or upon renewal of the ROP.