Fuel For Thought, by Capt. Bill Pike (continued)
Automatic, Immediate, Seamless
We spent a couple of hours doing a walk-through of the Energy’s engine room, a vast multilevel place that houses three giant 3,365-horsepower Wärtsilä 6L34DF dual-fuel generators forward, a matched set of 3,618-horsepower Alconza electric motors (driving the aforementioned fully nozzled, LIPS azimuthing thrusters) aft, and a phantasmagoria of machines and tanks (for LNG, diesel fuel, potable water, liquid drilling mud, methanol, and dry bulk) in between. While leading the way, Pacy enthused about the fuel that made the Energy so different from all the other PSV’s then so assiduously plying the Gulf of Mexico.
“The wear and tear on the engines is less with LNG because it’s way cleaner than diesel,” he explained. “We gotta deal with no soot on the boat at all. None!”
Pacy went on to describe a facet of the Wärtsilä dual-fuel system that is somewhat unusual but, he said, “never problematic.” Because a surfeit of LNG is always present in the piping that connects the Energy’s GVUs (i.e., gas vaporization units, which warm and gasify extremely cold LNG) to their dedicated 6L34DF generators, stopping her on short notice sometimes requires that the entire powerplant be momentarily switched to diesel, a fuel type that produces near-instantaneous, versus gradual, engine response.
“Let’s say I got a shrimp boat crossing my bow and I gotta put the brakes on in a hurry,” said Pacy. “The Wärtsilä system immediately trips to faster-reacting diesel power—it’s automatic, immediate, and seamless. Without checking the instruments, you can’t even tell it’s happening.”
Economy was the last point Pacy emphasized during our walk-through. Although diesel fuel was comparatively inexpensive at the time of my visit, it was, according to Pacy, still costing Harvey Gulf just a tad more than LNG.
“And due to this no-particulate-emissions thing,” he added, “I’m thinking that LNG will not only be the cheapest way to go in terms of Tier 4 and the other environmental-regulations that are coming, but it’ll also be the cheapest way for crews to live and work, in terms of pure, day-to-day practicality.”