Navy’s Green Dream Shattered: The End of the Hybrid Destroyer Era
The Navy is ceasing a project aimed at incorporating fuel-efficient hybrid electric drives in 34 destroyers, resulting in only one destroyer being outfitted with this technology, as reported by the Navy in a statement.
Pointing to “departmental priorities,” the service requested $6.3 million for 2018 to finalize the installation on the destroyer Truxtun but has removed funding for 2019 and subsequent years. The service has invested approximately $52 million in this initiative thus far. The total project was expected to cost $356.25 million, as detailed in the Navy’s FY2017 budget proposal.
“In alignment with the Department’s priorities, the President’s Budget 2019 withdraws funding from the Hybrid Electric Drive initiative for FY 2019,” stated Lt. Lauren Chatmas. “There are no further procurements or installations planned beyond DDG-103 in the Future Years Defense Program.”
The Navy will utilize Truxtun as a testing platform to assess whether the technology demonstrates long-term benefits, Chatmas elaborated.
“Installation on DDG-103 is in progress, and following its completion, the operational efficiency of HED on DDG-103 will be monitored and analyzed to determine the effectiveness of HED. This will inform future decisions regarding the implementation of HED.”
The initiative, developed in partnership with L-3, aimed to redirect power to the drive shaft, which drives the ship’s propellers, from the main LM2500 gas turbine engines to the vessel’s electrical generators at speeds under 13 knots. At these speeds, the ship could conduct night operations, ballistic missile defense, or anti-submarine actions but would struggle to keep pace with faster carriers.
As the initiative evolved and development progressed, numerous challenges emerged, according to a former Navy official who opted to remain anonymous. A primary concern was the high electrical demand required to operate the drive system on the ship’s two active generators.
Destroyers are equipped with three generators, with two operating while a third remains on standby, switching during maintenance or emergencies. Operating the electrical motor that turned the shaft while simultaneously powering the ship’s essential radars and associated systems exceeded the capacity of those generators.
“At that moment, you are just a single light switch away from potentially shutting down the entire ship,” the official explained.
Furthermore, operating the generators under such stress was not as fuel-efficient as they had anticipated.
These obstacles, although significant, could have potentially been mitigated through engineering solutions, noted Bryan Clark, a retired submarine officer and analyst with the Center for Strategic and Budgetary Assessments.
To Clark, halting the initiative seems somewhat myopic, considering the technology’s potential to substantially improve fuel efficiency in future vessels and classes.
“If it’s a fiscal decision, that’s reasonable,” he commented. “If it’s this versus investing in over-the-horizon anti-surface weaponry, that’s one thing. But if it’s this against another science and technology or research and development program — one of the critical challenges we face is learning how to enhance efficiency in specific missions. That knowledge would be invaluable.”
