Plant Applications: Software controls energy costs for car manufacturer

August 1, 2011

Situation

In a car factory with a few million square feet of floor space, turning lights off in unused parts of the plant saves a lot of energy and money.

General Motors realized that if it tied its lighting to the schedule of its conveyor, outside of the security lighting, it could reduce energy consumption in the plant significantly.

"Everything in a vehicle assembly plant is tied to the conveyor," said Mike Durak, global information technology manager with GM.

Resolution

Proficy® CIMPLICITY from GE Intelligent Platforms was already controlling the conveyor, so GM managers approved an application based on the software that schedules the lights to coincide with conveyor operation. This led to other discoveries of potential energy savings.

"A hidden benefit was that once we scheduled the conveyor, we had a good view into what the plant was doing, so we were able to schedule the on-and-off of big energy consumers in the plant, like air supply houses on the roof, ovens in the paint shop, lighting, water, and compressed-air generators."

Millions of square feet of plant floor space now are controlled by the client/server-based HMI/SCADA software. Employees are not affected by the automatic shutoff of lighting and equipment. From the lighting perspective, lights are turned on two or three minutes before employees arrive at their workstations. The general building lighting goes on a few minutes earlier.

"We've also scheduled different turn on/shutoffs on weekends," said Durak. "For instance, ovens in the paint shop need two hours to warm up, so we need to take that into account when we turn them off. Therefore, we have different times for end of shift, weekends, extended long production, lunch, and end of day, just to name a few."

For GM, annual savings versus one-time implementation costs at 20 individual plants were as follows:

• For weld water pumps/cooling towers/fans, chilled water, and exhaust fans—7 times greater
• For hydraulic pumps, ovens, and weld water pumps/cooling towers/fans—4 times greater
• For HVAC and line lighting—5 times greater
• For ventilation, line lighting, and air supply/exhaust—5 times greater

GE Intelligent Platforms, Routes 29 and 606, Seminole Trail, Charlottesville, VA 22911, 800-433-2682