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EMA European Office, C.P. 65, CH

- 1231 Conches, Switzerland Telephone: +41 22 784 3357 Facsimile: +41 22 784 3349

EMA is a Non Governmental Organization in Special Consultative Status with the Economic and Social Council of the United Nations Two North LaSalle Street
Suite 2200 Chicago, Illinois 60602

Tel: 312/827

- 8700

Fax: 312/827

- 8737 www.enginemanufacturers.org

April 13, 2007

Mr. Jaime Pagan Energy Strategies Group US Environmental Protection Agency

D243

- 01 Research Triangle Park, NC 27711

RE: Follow

- up Issues on CI NSPS Rule for Greater Than 30 Liters Engines

Dear Mr. Pagan:

In our discussio ns and c orrespondence with EPA staff on open issues regarding the NSPS regulat ion for CI (Compressio n Ignit io n) engines, one outstanding issue is our continuing

concern about the emissio ns standards for engines greater than 30 liters in areas where lower qualit y f uels are being used. This issue was discussed in our letter to you dated September 29, 2006, and in a fo llow

- up email wit h Mr. Horowitz on December 1, 2006.

Briefly, our concern is with the abilit y o f engine

- based power systems to meet the NOx

and PM li mits established in the CI NSPS when higher sulfur fuels or fuels mixed with used

lubricat ing oil are allowed by the NSPS. This issue is primarily limited to the US Territories and Alaska where low sulfur diesel fuel may not be available and where the loc al populat ion relies on the use of diesel engines for the production of primary power. As we discussed, the use of high sulfur, lower qualit y fuels will create problems with the successful use of SCR (Select ive Catalyt ic Reduction) and ESP (Electro

- static Precipitators) that are needed to reach the strict

emissio ns limit s established in the final CI NSPS. Addit io nally, even if technically feasible,

meet ing the limits will be of such high cost as to severely impact the captive local populat ion

that relies on these engine facilit ies as their only viable source of power.

In previous discussio ns on this issue, EPA indicated that lower sulfur fuel o ils were likely to be available in US territories and Alaska. However, this low sulfur fuel, even if available

, will be more expensive. Depending on location and availabilit y, the light, low sulfur fuel can be as much as two times the cost of heavier diesel fuel. Given the economics and small populat ion

size in so me of these remote locations, it is not likely th at local operators will vo luntarily opt to use low sulfur fuel when a much lower cost option is available. In addit ion, even if low sulfur fuel is available, many locat ions still maintain the practice of mixing used engine lube oils. Doing so introduces several heavy metal contaminants to the fuel which will be harmful to any SCR systems deplo yed.2

The use of SCR also requires a minimum flue gas temperature (dependent on the sulfur content of the fuel) to prevent clogging of the elements of the react or that will be especially challenging to maintain in plants with frequent start

- ups and shut

- downs. With respect to the use of ESP, there is very limited experience wit h this techno logy in stationary engine power plants.

The established PM emissio n limi t requirement in the CI NSPS is also very strict. In comparison to the European Unio n Best Available Technology (BAT) level published in the guidelines “Integrated Pollut ion Prevent ion and Control, Reference Document Best Available Techniques for Large Co mbustion Plants (July 2006)” the NSPS PM standard is about 2.5 times more stringent and is thus beyo nd best determined technology for large stationary engines.

Consequent ly, we believe that the fuel issues discussed earlier in the territories and

Alas ka are not satisfactorily reso lved and that some relief fro m the emissio ns standards for engines greater than 30 liters are st ill needed.

Another issue of concern is the large discrepancy between stationary engine emissio ns standards for engines near the 30 liters cut point. For engines in the 25

- 30 liters size class, EPA

has established emissio ns limits based on marine engine standards (Table 3 of the Preamble) of 11.0 g/kW for NOx +THC and 0.5 g/kW for PM. However, if the engine is designed wit h a > 3 0 liters displacement, the emissio ns standard drops significant ly to 1.6 g/kW NOx and 0.15 g/kW PM. This large difference in the applicable emissions standards creates a strong incent ive to use smaller engines, especially in areas where only higher sulfu r fuels are available, since the engines less than 30 liters in size are likely to be able to achieve the emissions standards wit hout aftertreatment even when using higher sulfur fuels. This causes disruptions in the market and works against larger, more efficient engines.

As an example, one engine manufacturer has a current engine model that has a cylinder size less than 30 liters and a new model that is greater than 30 liters. The newer model has many improvements, provides owners more flexibilit y is power range, and is nearly 3% more energy efficient. However, the current CI NSPS regulat ion would require the newer engine to meet

much lower emissio ns standards and would require the addit ion of aftertreatment, thus adding significant ly to the capital and operating costs. Because the CI NSPS emissio n standards for engines less than 30 liters are much less stringent, prospective owners are likely to choose the older, less efficient and higher emitt ing engine based on cost alone. EMA does not believe th at this is a logical or desired outcome.

As a solut ion, EMA again requests that EPA consider revising the emissio n standards applicable to engines greater than 30 liters/cylinder in two ways.

First, relief needs to be provided in areas where low sulfu r fuels are not required. Even if low sulfur fuel is available in these areas, the cost different ial is sufficient to expect that it will not be used, thus creating significant concerns about the techno logical and cost

- effect ive

feasibilit y o f meet ing the

emissions standards for those applicat ions.

Second, the very large differential in emissio ns standards between engines less than 30 liters and greater than 30 liters needs to be resolved by providing more equivalent standards for engines greater than 30 liters when operating on the same fuel. One way to address this3

disrupt ion is to establish different emissio n standards based on plant size within the >30 liter engine category. Engine unit size can vary considerably fro m 2.5 MW to 80 MW for engines in

t he greater than 30 liter displacement size category, and a power plant often consists of mult iple engine units. EMA recommends that EPA maintain the current emissio n standards for plant sizes greater than 20 MW, but establish less stringent emissio n stan dards for plants less than or equal to 20 MW. This recommendat ion is similar to the regulatory approach used in Europe where large thermal power plants (>50 MWth, about 20MW output) have to use BAT and smaller plants have less stringent emissio ns standard s.

EMA again reco mmends that the fo llowing emissions standards be established for plants

less than 20 MW:

NOx 12.4 g/kWhr

PM 0.54 g.kWhr

EMA understands that EPA is still working on issues related to the CI NSPS and would appreciate your effort s to address the above issues in the near future. Since the final rule and its

emissio n standards are in effect and there currently are real

- world issues related to these topics, EMA requests that the issues be reso lved as soon as it is practical to do so

.

Please do not hesitate to call me if you have any questions.

Very truly yours,

Joe Suchecki Director, Public Affairs