Trimming electricity usage is critical for manufacturing operations that want to reduce their carbon footprint. These savings come from steps as simple as changing light bulbs to building new facilities that eliminate the waste that comes when energy generation creates heat.
For example, a cogeneration plant was built at Northrop Grumman’s Palmdale Manufacturing Center. In conventional power generation, about two-thirds of the energy input escapes as waste heat to the atmosphere.
The Palmdale Cogeneration Plant produces 2.8 MW of electrical power while recovering this waste heat. Depending on the season or need, this recovered energy may be used to heat occupied areas or, through absorption chillers, for air conditioning. Energy savings for cogeneration facilities typically range between 20 and 40%,” said Bobby Wilson, Northrop Grumman’s Palmdale Facilities Manager.
Production equipment on plant floors is being redesigned to consume less energy without reducing throughput. A growing number of machines employ variable frequency drives (VFDs) to conserve energy.
“VFDs provide an energy-efficient means to control the rotational speed of electrical motors. As an example, we typically use VFDs to control fan motors in painting operations,” said Wilson.
These drives are often equipped with soft-starting features that decrease motor starting current to about 1.5 to 2 times the operating current. Soft starting reduces thermal and mechanical stresses when units start, bringing the additional benefit of longer lifetimes.
“By gradually bringing fan speed up to operating conditions, impacts of fan starts on electrical systems are significantly reduced,” said Rick Doria, Facilities Manager at Northrop Grumman’s East Coast Manufacturing & Flight Test Center.
Factories are also adopting a technique used in many homes: changing light bulbs. Increasing efficiency in lighting is one of Bell Helicopter’s many energy conservation initiatives.
Lights all over Bell have been replaced with new energy-efficient lamps. All heavy-duty illumination lights have been replaced with fluorescents, and T12 lights with magnetic ballasts have been replaced with T8 lights with electronic ballasts. By itself, the use of T8 lights cut energy consumption for lighting nearly in half.
Northrop Grumman has also targeted building lighting systems. Its Green Lights program upgrades lamps, ballasts, and other lighting components systematically, replacing them with energy-efficient models.
“Depending on the manufacturing center, our energy conservation program has achieved energy reductions that range to more than 10% since 2003,” said Frank Murphy, El Segundo Facilities Manager, Northrop Grumman.