TEI Releases Report on SCR Systems and Diesel Exhaust Fluid
Industry stakeholders provided analysis of technology, market availability and policy considerations.
Aug 13, 2026 | 2 min read
The Transportation Energy Institute (TEI) released a new report examining Selective Catalytic Reduction (SCR) systems and the Diesel Exhaust Fluid (DEF) market, providing objective information on a technology that has played a critical role in reducing nitrogen oxide (NOx) emissions from diesel-powered vehicles and equipment.
SCR systems, which use DEF to convert NOx emissions into harmless nitrogen and water, have helped drive significant improvements in air quality across the United States. According to the report, SCR-equipped vehicles and equipment have contributed substantially to NOx reductions achieved since 2010, while also enabling engine designs optimized for fuel efficiency.
To develop the report, TEI convened a diverse task group representing vehicle operators, vehicle and engine manufacturers, diesel fuel and DEF producers and distributors, and public health and environmental interests, it said.
"As discussions continue regarding EPA guidance and proposed regulatory changes affecting SCR and DEF systems, stakeholders need access to reliable, objective information about these technologies and the marketplace that supports them," said John Eichberger, TEI executive director. "This report is intended to inform those conversations by presenting facts and current market conditions rather than advocating for a particular policy outcome."
The report highlights:
- The role NOx emissions play in ozone formation and associated health and economic impacts.
- The significant reductions in NOx emissions achieved through widespread deployment of SCR technology.
- The extensive availability of DEF throughout North America, with more than 100,000 retail locations offering product access.
- Recent EPA guidance intended to address operator concerns related to engine derate requirements.
- The importance of maintaining DEF availability and proper SCR system operation to preserve emissions reductions, engine performance, and equipment durability.
According to the report, continued access to high-quality DEF and proper operation of SCR systems remain essential to sustaining air quality improvements while supporting efficient diesel engine performance.
