[Gasification] Emissions fines

[Tom Miles]

Tom,

The reported violations all point to management:

"that [plants] violated the air permits issued to them by the District by emitting air pollutants including nitrogen oxides, sulfur dioxide, and carbon monoxide in excess of the permit limits.

In addition, they failed to perform timely source testing to measure emissions of various air pollutants. They also didn't properly install and operate emissions control systems for nitrogen oxides or certify the continuous emissions monitoring systems.

The plants also violated various district rules including requirements for emissions control plans, according to the EPA."

Chowchilla II (1990) and El Nido (1988) are a couple of the oldest biomass plants built in California under the PURPA (Standard Offer #4) subsidies. They have both had several owners. They each generate 10 MWe. I witnessed El Nido burning straw when it was commissioned in 1988. They are bubbling fluidized bed combustors as described by George Wiltsee in his review for NREL titled, "Lessons Learned From Existing Biomass Plants," pp 44 ff. http://www.nrel.gov/docs/fy00osti/26946.pdf 
    
At least one gasifier supplier, Nexterra, has recently shown that they can perform well in emissions compared to combustion technologies. That does not mean that all gasifiers are cleaner than combustors. It means that plants provided by that technology provider have performed better. Combustors or gasifiers of comparable capacities have to meet similar standards and generally require similar pollution control equipment. Any emissions advantage that gasification appeared to have was eclipsed by more stringent EPA regulations by 1980 which resulted in increased emission control equipment requirements.  

The recent Levelton Associates study for Nexterra, "EMISSIONS AND TECHNOLOGY REVIEW OF SELECTED BIOMASS CONVERSION SYSTEMS" October 13, 2010, is interesting in the light of the recent MACT (Maximum Achievable Control Technology) and other (e.g. PM 2.5 particulate matter) standards promulgated by federal and state agencies for biomass conversion systems. We haven't seen many comparative studies of emissions for biomass plants, gasifiers or combustors, and the extensive data compiled by EPA for the MACT ruling is difficult to interpret. Nexterra's reported emission performance could give it a competitive advantage in cases where owners are concerned about permitting. But it didn't prevent one county (Thurston, WA) from simply declaring a moratorium on biomass plants until more information is available. 
http://www.co.thurston.wa.us/planning/biomass/docs-evergrn/Attachment-G=Levelton-Emissions_Report_Executive_Summary_Oct_2010.pdf 

It is not clear whether a 10 MWe engine-genset system would have to comply with more stringent emissions regulations than a combustor, or gasifier-boiler. Today's stationary generator regulations are based on Natural Gas as a fuel so CO requirements are very low. Most states have told us that they will deal with gasifier-engine systems on a case by case basis. If anyone has permitted a 10 MWe gasifier-genset system it would useful to know about. In any event a flare used for startup/shutdown or upsets will have to be fully enclosed and probably run with a standing natural gas or oil pilot burner.

Anyone interested in this topic should review the information presented to the Thurston County, Washington, planning department during consideration of biomass systems in the county including a gasifier at Evergreen State College. 
http://www.co.thurston.wa.us/planning/biomass/biomass-presentations.html
  

Tom