In 2008, the California Air Resources Board (CARB) laid out new regulations that mandated strict reductions in air pollutants produced by container, cruise and refrigerated cargo ships docked at the busiest ports in the state. Scaled upward over the following years, the key requirements of the regulation called for a minimum cut of 80% in emissions starting in 2020. The directive—the strictest such pollution control guidelines in the country—has sped the implementation of so-called “cold ironing,” in which ships damp their main and auxiliary engines while at berth and “plug-in” to power onboard generators and other equipment with high-voltage electrical…