Toyota issued an environmental challenge to itself — to completely eliminate carbon dioxide emissions from its global production plants by 2050. To meet these ambitious goals, it is taking steps to reduce its energy usage and move to reusable energy.
Toyota Motor Manufacturing, Alabama, in Huntsville, is one location where the automotive manufacturer has already taken steps in its energy reduction, which has had a side benefit — cutting costs too.
The Huntsville plant makes 4-cylinder, V-6 and V-8 engines for some of the manufacturers’ most popular vehicles like the Tacoma, Tundra and Highlander. Workers at the plant receive engine components that have been cast at other facilities to machine and assemble into engines that go into vehicles at yet another plant.
The plant’s air compression system is crucial to the process. Comprised primarily of five large centrifugal air compressors, the system provides air across the 1.2 million-square-foot plant for various machine processes, automation and drying engine components.
Compressed air systems are energy intensive. The system in Huntsville was no exception, accounting for 25 percent of the plant’s annual energy costs. And the legacy controls made the Huntsville plant system even a bigger energy user.
The aging controls were slow to start up the compressors and didn’t allow them to work together as an integrated system. Because of these limitations, team members had to keep compressors online more than necessary.
The plant’s electrical contract also was a challenge. The contract charges more for energy consumed during peak usage hours. When team members needed to start one of the large compressors during peak time, a single machine start-up could increase the plant’s electricity bill by 100 percent of the day’s energy charges.
To rein in energy costs, TMMAL decided to upgrade the plant’s air compressor control system. For the job, they turned to IZ Systems and Case Engineering, a machine build partner in the Rockwell Automation PartnerNetwork program.
Locally, Case migrated the controllers on the five large compressors to its AirLogix control solution, which includes a PanelView Plus 7 operator interface, providing workers performance and diagnostic data on each compressor.
At the plant level, Case used its AirMaster load-sharing solution to create a master air control system. The solution is based on the ControlLogix platform and uses the FactoryTalk View SE software for data collection and visualization. Case worked with IZ Systems to install a 5,000-gallon storage tank for boosted compressed air of 500 psi to allow the system recovery time without faulting. A modulating valve delivers air during high air demand periods. This stored air provides a smooth transition when an additional centrifugal machine is required to meet the plant’s air demand.
From these upgrades, the plant reduced annual energy usage by nearly 1 million kilowatt hours per year or about $68,000 annually. This doesn’t include the savings realized by avoiding start-ups during peak-usage hours.
The updated controls also help the compressors run more efficiently and the master controller monitors pressure and airflow, which starts or stops compressors to match demand. It will draw compressed air from the high-pressure storage tank while a compressor comes online or to ride through demand surges.
“The way it’s set up now, we always have enough pressure in the storage tank for any dips or compressor failures,” said Eddy Kiggen, a facility specialist with Toyota. “Even if the next compressor we try to start fails, we can start yet another compressor and people on the plant floor won’t know anything happened.”
Team members have access to air pressure and flow, energy usage and critical data at each machine, in real-time, which also helps when troubleshooting problems. Toyota and Case Engineering can view that same data from anywhere using remote access.
“After electricity, air is the most important utility we have, so we keep a close eye on it. I look at the data daily to see how the system is performing and to review its efficiency. I get a text message if we have an issue, like a pressure drop or the storage tank falling below a certain level,” Kiggen said. “We also like having Case connected and let them know of an issue so they can get online to fix the problem right away.”
Toyota is now looking to replicate this project elsewhere for similar energy savings while continuing to drive toward zero CO2 emissions.