Company Background

Located in Grangeville, Idaho, this facility is designed with exceptional flexibility to make a multitude of products, producing up to 250 million board feet per year for the world market. The mill creates 2×4 through 2×8 high quality dimensional lumber up to 16 feet from Douglas Fir and White Fir, as well as 1×4 to 1×8 Ponderosa Pine and Spruce/Lodgepole, and a small volume of Cedar and Idaho White Pine specialty products.

Air Compressor Audit & Overview

Adam Miller, maintenance superintendent, had confidence in his compressed air system. Rogers Machinery Company reviewed their system, and after presenting inefficiencies along with energy saving ideas, mill management agreed to a formal audit of their system. Data loggers were connected to gather information over a typical two (2) week period.

After data collection, experts from Rogers presented the information and pointed out what was working and what was using too much energy. Armed with this information Energy Efficiency Measures (EEMs) were prepared with;

Annual energy savings
Implementation Costs
Utility Incentives
Simple Payback.

Idaho Forest Group chose to proceed with compressor modification to variable speed drive on main and fan motors, upgrades to dryer load controls and to bypass flow controller to lower system pressure.

Once installed, Rogers returned and again connected data collection equipment to fine tune the controls, educate the system owner, and prove the savings.

New Upgraded Compressed Air Benefits

Energy Savings of over 1,289,000 kWh annually
Electrical cost savings of $77,000 annually
Simple payback of just over one year
Reliable, clean compressed air

Compressed Air Finance Incentives

Incentives provided by Avista under their program provided the motivation to move the project forward.

The existing machines were new in 2005 and the variable speed option was explored at that time however incentives were unavailable. At that time the payback and additional cost led the customer to a less efficient system to minimize out of pocket. Current incentives by the utility made this project the common sense solution.

Incentives provided approximately 50% of the implementation costs which reduced the simple payback from 3.7 to 1.8 years. A return on investment upper management thought was worthy.

Air Compressor System Upgrade Summary & Savings

The original sawmill system consisted of three single-stage fixed speed compressors operating with modulation and unloading controls. As well as a single large air dryer and receiver.

Proposed and installed system consisted of converting two 300 horse units to VFD control to match demands, installing dryer load controls and storage. Compressor sequencer was built specific to their system to allow both VFD units to ramp together or unload one unit. This system allows the existing flow controller to be bypassed and the VFD to control pressure.

The ability to show the calculated savings based on actual measured data coupled with Rogers Machinery’s reputation provided the foundation for a project that is beneficial to everyone involved. Measurement and verification of system savings and ongoing customer training and support reinforces our relationship with the customer so we remain their source for honest realistic solutions they can rely on. Non-energy benefits in the form of consistent plant pressure allowing for better end product for the mill and reduced product waste are being experienced.