On May 25, 2010, the U.S. EPA proposed revisions to the Standards of Performance for Stationary Compression Ignition (CI) and Spark Ignition (SI) Internal Combustion Engines (NSPS IIII and NSPS JJJJ). The proposed revisions address comments received related to current NSPS IIII and NSPS JJJJ requirements and incorporate recently promulgated standards for new marine engines into the standards for similar new stationary engines. The most notable changes outlined in the proposed rule include the following:
- Proposal of more stringent standards for CI engines with displacements greater than or equal to 10 liters/cylinder and less than 30 liters/cylinder
- Revisions to NSPS IIII requirements for CI engines having displacements greater than or equal to 30 liters/cylinder
- Allowance for additional flexibility related to operations and maintenance requirements for owners and operators of affected NSPS IIII and NSPS JJJJ engines
- Minor revisions to NSPS JJJ to mirror revisions proposed for CI engines and provide consistency between the two rules, where appropriate
These proposed revisions are discussed in greater detail below.
EPA is proposing more stringent standards for stationary CI engines with displacements greater than or equal to 10 liters/cylinder and less than 30 liters/cylinder that are consistent with recent revisions to standards for mobile marine engines. These proposed standards, which would not take effect until 2013, at the earliest, take the form of two tiers. The Tier 1 standards, which include standards divided by engine displacement, are based on engine technology already in use or expected to be used for other mobile and stationary engines. The Tier 2 standards, which are divided by maximum engine power, are expected to be met by use of catalytic exhaust aftertreatment.
The proposed revisions to NSPS IIII for CI engines with displacements greater than or equal to 30 liters/cylinder are based on comments received from engine manufacturers and owners and operators related to current rule requirements. The proposed revisions to NSPS IIII requirements for CI engines with displacements ≥ 30 liters/cylinder include, but are not limited to, the following:
- Incorporation of specific NOx standards based on installation date. Most stringent standards presume the use of exhaust aftertreatment and would apply to CI engines installed after January 1, 2016. The most stringent standards, requiring exhaust aftertreatment, would not apply to emergency engines.
- Revision of the PM standard for emergency engines to 0.40 g/kW-hr
EPA is also proposing revisions to NSPS IIII and NSPS JJJJ to provide additional flexibility to owners and operators of affected engines related to operations and maintenance requirements. The proposed rule allows for owners and operators to develop their own operation and maintenance plans as an alternative to manufacturer specified plans. Engines operated under these alternative operation and maintenance plans would be considered as operating in a non-certified manner. Therefore, these engines would be subject to additional recordkeeping and testing requirements, depending on the size of the engine.
The proposed minor revisions to NSPS JJJJ to improve consistency with NSPS IIII are specifically related to definitions contained within the rule and compliance requirements for owners and operators. Additional minor revisions to NSPS JJJJ and NSPS IIII are proposed to correct errors in the current rules. In addition, EPA is proposing to include a definition of "reconstruct" that would be specific to NSPS IIII and NSPS JJJJ. As part of this proposed definition, EPA is also proposing that a reconstructed engine meet the standards required for the model year in which the engine undergoes reconstruction, if the reconstructed engine meets specific criteria outlined in the proposed rule.
Public comments on the proposed revisions to NSPS IIII and NSPS JJJJ must be received within 60 days of the publication date of the proposed rule in the Federal Register.
Additional information regarding the proposed rule is available via the EPA website.