U.S. EPA Proposed NSPS Revisions – Stationary Gas Turbines and Stationary Combustion Turbines

In the August 29, 2012 Federal Register, U.S. EPA published a proposal to amend various portions of the New Source Performance Standards (NSPS) for Stationary Gas Turbines (40 CFR Part 60 Subpart GG) and Stationary Combustion Turbines (40 CFR Part 60 Subpart KKKK).  The proposed amendments to specific sections of these regulations are intended to resolve issues related to a September 5, 2006 petition for reconsideration filed by the Utility Air Regulatory Group (UARG).  U.S. EPA states that the proposed amendments would increase the environmental benefits of the existing requirements because the emission standards would apply at all times and would promote efficiency by recognizing the environmental benefit of combined heat and power (CHP) and the beneficial use of low energy content gases.

U.S. EPA is proposing to amend the applicability criteria such that only the combustion turbine engine will be considered when determining if a stationary turbine is a new or reconstructed turbine.  The theory here is that this approach reflects the environmental benefits of heat recovery and output-based standards, which was the intention of the original rule.  The proposed revisions also make it clear that the replacement of a turbine engine at a CHP or combined cycle facility that is not currently subject to Subpart KKKK would result in a “new” turbine that would now be subject to the rule.

A second proposed change is an exemption from the Subpart KKKK sulfur dioxide (SO₂) standards for turbine owners that meet the SO₂ provisions of 40 CFR Subparts J or Ja (petroleum refineries.)  Under this proposal, an exemption from the Subpart KKKK SO₂ standards would also be provided to turbine owners that have a federally-enforceable gaseous fuel sulfur limit of no more than 20 grains of sulfur per 100 standard cubic feet or a liquid fuel limit of no more than 0.050 percent sulfur (500 ppm) by weight. 

The proposed rule changes would also allow turbine owners who are currently subject to Subpart GG to petition U.S. EPA to comply with Subpart KKKK in lieu of complying with Subpart GG and any associated steam generating unit NSPS.  The final portion of the proposed changes to these rules centers on U.S. EPA’s requests for comments relative to situations when turbines are overhauled or refurbished offsite, resulting in the inability to perform a reconstruction analysis.  Such an analysis is necessary to determine whether the cost of the new components exceeds 50 percent of the fixed capital cost of a new facility (i.e., meets the definition of a “reconstructed” facility).  Essentially, U.S. EPA proposed to define overhauls or turbine refurbishments where the combustor itself is replaced as reconstructed, if the owner is otherwise not able to perform a reconstruction analysis.

The proposal also includes changes to the nitrogen oxides (NO_X) standard for turbines that burn multiple fuels by basing the standard on the type of fuel being burned in the turbine engine.  The existing rule considers the total heat input to the turbine, including associated duct burners.  NO_X emissions would apply during periods of startup and shutdown, with an affirmative defense for malfunction periods.  For SO₂, the proposed changes include clarifying that a source using a fuel analysis to demonstrate compliance must include all sulfur compounds.  Sources would be allowed to use fuel blending to achieve the SO₂ standard as long as the average fuel fired meets the standard at all times.  U.S. EPA is also proposing to expand the existing 0.15 lb SO₂/MMBtu heat input emission standard to include turbines that combust 50 percent or more of any gaseous fuels that have heating values less than 750 Btu/ft³ (e.g., blast furnace gas, coke oven gas, coal bed methane, and landfill gas).  Like the proposed NO_X emission standards, the proposed SO₂ standards would also apply during periods of startup and shutdown.

U.S EPA is requiring comments on these proposed rule changes to be submitted on or before October 29, 2012.