Energy Efficiency Survey Aboard USS Princeton CG-59

The report finds that the USS Princeton's cruise-condition electric load of 2 MW could be reduced by 20–50%, potentially lowering total fuel use by 10–25%. The most significant savings are identified in motors, pumps, fans, chillers, and lighting. A critical finding is that current operational practices—specifically running two gas turbine generators (GTGs) in parallel at partial loads—negate approximately 75–80% of the fuel savings that would otherwise result from electrical load reductions. The report recommends transitioning to single GTG operation during routine cruise conditions, implementing Variable-Speed Drives (VSDs), and adopting premium-efficiency equipment. More intensive strategies, including the use of fuel-cell generators and low-speed electric propulsion, could potentially reduce total fuel use by roughly 75%.

• The cruise-condition electric load of the USS Princeton was observed at 2 MW, with a potential for reduction of 2050%, which could decrease fuel use by 1025%.
• Current operational practices of running two gas turbine generators (GTGs) in parallel at partial loads significantly diminish the fuel savings gained from reducing electrical loads; approximately 7580% of potential fuel savings are lost unless this practice is changed.
• Operating a single GTG instead of two during routine cruise conditions could reduce total fuel use by an estimated 14%.
• Combining single GTG operation with a 20% reduction in electrical load could result in an 18% saving in total fuel use.
• The most aggressive efficiency strategy, combining a 50% electric load reduction with fuel-cell generation and low-speed electric propulsion, could reduce total fuel use by approximately 76%.
• The ship's fire pumps are identified as a major source of waste, consuming approximately 210 kW of electricity to maintain pressure by continuously pumping seawater overboard.
• The existing centrifugal chillers are described as among the most inefficient evaluated by the team, with an observed performance of 1.1 kW/ton compared to a best-practice benchmark of 0.45 kW/ton.
• Lighting loads could be reduced by approximately 40% through the use of T8 lamps, electronic ballasts, and improved lighting design, which would also reduce the associated HVAC cooling load.
• The report recommends the installation of Variable-Speed Drives (VSDs) on all variable loads, including pumps and fans, to avoid the inefficiency of throttling or bypassing flow.
• The ship's power factor is nominally 0.8, which is suboptimal; increasing it toward 1.0 would reduce distribution-system losses and increase distribution capacity by 20%.
• The use of ozone in laundry systems could reduce total water use by approximately 25% and decrease hot water requirements by at least 90%.

APA

Lovins, A. B., Lotspeich, C., Perkins, R., Rogers, J., & Orrett, E. (2001). Energy Efficiency Survey Aboard USS Princeton CG-59. RMI. https://rmi.org/app/uploads/2017/06/RMI_Energy_Efficiency_Survey_Aboard_2001.pdf

Chicago

Lovins, Amory B., Chris Lotspeich, Ron Perkins, Jim Rogers, and Edwin Orrett. Energy Efficiency Survey Aboard USS Princeton CG-59. RMI, 2001. https://rmi.org/app/uploads/2017/06/RMI_Energy_Efficiency_Survey_Aboard_2001.pdf.

Wikipedia

{{cite report |last1=Lovins |first1=Amory B. |last2=Lotspeich |first2=Chris |last3=Perkins |first3=Ron |last4=Rogers |first4=Jim |last5=Orrett |first5=Edwin |title=Energy Efficiency Survey Aboard USS Princeton CG-59 |publisher=RMI |date=30 June 2001 |url=https://rmi.org/app/uploads/2017/06/RMI_Energy_Efficiency_Survey_Aboard_2001.pdf |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{lovins2001energy, author = {Lovins, Amory B. and Lotspeich, Chris and Perkins, Ron and Rogers, Jim and Orrett, Edwin}, title = {{Energy Efficiency Survey Aboard USS Princeton CG-59}}, institution = {RMI}, year = {2001}, month = jun, url = {https://rmi.org/app/uploads/2017/06/RMI_Energy_Efficiency_Survey_Aboard_2001.pdf}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }