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Fleet Retrofit Rule Development

Business Objective

Over the past 25 years, the ALG has represented and provided technical advocacy to trade associations regarding the development of fleet retrofit regulations that have been developed by the California Air Resources Board (ARB). These rules include the Portable Engine Air Toxics Control Measure and permitting program, the Large Spark Ignition (LSI) rule, the In-Use Off-Road Diesel rule, and the On-Road Diesel rule. Taken together, these fleet retrofit regulations seek to reduce emissions from internal combustion engines used to power on-road and off-road equipment, and will require affected owners to spend over $6 billion to modify and-or replace their equipment. The key objective for these trade associations was to secure meaningful reductions in emissions from member fleets in the most cost effective manner.

Technical Approach

ALG worked with trade association members and ARB staff to properly define emission inventory baselines, which initially were not properly understood by state regulators. In addition, ALG performed control technology analyses, which included testing of engine exhaust characteristics, technical analyses of verified control technology, and assessments of zero emission/alternative fuel technology.


Working with our clients' technical staff and legal counsel, ALG leveraged its technical expertise with ARB staff to develop acceptable alternative conversion strategies and suggest modifications to these proposed regulations to streamline monitoring, recordkeeping and reporting requirements. Additionally ALG helped to secure credits for conversion to alternative fuels, reduced fleet size, and use of on-road technology. These modifications achieved similar emission reduction benefits as those proposed by the ARB, but at substantially reduced cost to our clients. ALG continues to work with these trade associations in the implementation of the ARB fleet rules.

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