Retrofitting Diesel Electrical Generators for Emission Reduction

Diesel generator sets (gen-sets) are used routinely to supply electrical power. Hospitals, businesses, and small communities use gen-sets to help reduce costs by load leveling and provide emergency power during blackouts (either scheduled or unscheduled). Recent power outages in California have led to large increases in the purchase of gen-sets, primarily for providing emergency power. In addition to providing value associated with load leveling and emergency power, gen-sets have an added value in that they can be installed relatively rapidly.

Although gen-sets are, in principle, under U.S. Environmental Protection Agency (EPA) regulation, many of these gen-sets are being rapidly installed with minimal concern for EPA emissions and exclusively focus on providing back-up power to avoid blackouts. The net effect of these events should be an increase in air pollutants (mostly NOx) as these gen-sets are brought online.

In Phase I, Compact Membrane Systems, Inc. (CMS) met and exceeded all project goals. This included: (1) demonstration of 50 percent NOx reduction while having minimal effect on other pollutants, (2) fabrication of prototype membrane systems/devices for easy installation or retrofit into diesel generators, and (3) enhanced overall membrane/system performance to perform better even when only low turbo pressure is available.

This success has led to the active participation in the project of a major industrial gas membrane company, a major diesel generator company, the U.S. Navy, and a major university. The participation of these groups will enhance Phase II and subsequent commercialization.

In Phase II, CMS will design and build full-size retrofit kits and install them on intermediate-scale diesel generators (e.g., 1,500 kw). Working with their diesel generator partner, CMS will modify turbocharger operating conditions and engine operating conditions to reduce NOx emissions and have a minimal effect on particulate emissions. Working with their industrial gas partner, CMS will optimize membrane design to match engine needs. The company also will demonstrate performance over an extended period of time to show system ruggedness. CMS will perform an economic evaluation to demonstrate that the retrofit system is cost effective compared to alternative systems.