I spent last week at the 2010 Power Gen Electric Power Show in Orlando, FL, looking for information affecting at least three of our publications in addition to Grading & Excavation Contractor. The others are Distributed Energy, MSW Management, and Water Efficiency, whose readers are or soon will be affected by Tier 4 Interim—followed shortly by Tier 4 Final—emissions standards.Given that the information I gleaned is less than a week old, and the deadline for Tier 4 standards scheduled to go into effect in 2011 is less than two weeks away, you’d think I or anyone else could tell you with absolute certainly what those standards will be…but that ain’t the way it is, folks. However, what follows appears to be what we can expect in the US. Lord knows what our neighbors to the north will do.The regulations cover four key emissions generated by diesel engines:
1. Oxides of nitrogen (NOx) are gases that form when fuel is burned with excess air.
2. Particulate matter (PM) is the name given to tiny bits of solids and liquids that form during the combustion process.
3. Hydrocarbons (HC) are gaseous compounds that result from unburned fuel and lubricating oil.
4. Carbon monoxide (CO) is the colorless, odorless gas produced when carbon in fuel is not burned completely.
Diesel engines only emit a small amount of HC and CO, so the industry focuses primarily on NOx and PM. These two types of emissions are inversely related; meaning a reduction in one generally causes an increase in the other. This is one reason why it is particularly challenging to meet the standards.In addition, crankcase emissions are now regulated.Tier 4 Interim regulations are phased in by power rating:
* Engines rated <56 bkW were subject to the standards in 2008.
* Engines rated ³130 bkW ³560 and >560 bkW will be affected starting in 2011.
* Engines rated ³56 bkW <130 must meet the new regulations beginning in 2012.
Finally, take a look and the presumed difference between Tier 4 Interim and Tier 4 Final standards.Tier 4 Final standards will further reduce diesel engine exhaust emissions from Tier 4 Interim levels. The level of reduction varies according to engine power and is summarized below for engines typically found in genset applications
|
Engine Power
|
NOx Reduction
|
PM Reduction
|
|
bkW <19
|
No change
|
No change
|
|
³19bkW <37
|
37%
|
90%
|
|
³37 bkW <56
|
No change
|
90%
|
|
³56bkW <130
|
88%
|
No change
|
|
³130bkW:<560
|
80%
|
No change
|
|
>560bkW:<900
|
80%
|
70%
|
|
>900 bkW
|
No change
|
70%
|
In the new year, we will do a comprehensive article on Tier 4 standards that hopefully will remove some of the mystery surrounding the subject.