Voices: Magazine Exclusives

From Field Corn to Ethanol to Fueling a Pump Near You

CGB's Goal Is to Enhance the Local Economy and Community by Working Every Day to Improve the Plant and Its Process to Be Part of the Solution to the Country's Energy Needs

By Carbon Green BioEnergy, LLC


When Mitch Miller and his team of industry veterans formed Carbon Green BioEnergy, LLC (CGB), they had a vision to own and operate an ethanol plant. The team raised enough equity to purchase a mothballed, two-year-old plant in Lake Odessa, Mich. that had been sitting idle since it went bankrupt in 2008. CGB purchased the plant in 2009 at a time when many thought the ethanol boom was going bust. However, the team strongly believed in the future of ethanol as a sustainable, clean fuel that creates jobs and reduces the country's dependence on foreign oil. Today, CGB's vision for the future has fueled a benchmark plant turnaround that is yielding outstanding results for the company and the community.

CG1409 GreenBioEnergyPlantChallenge

In June 2009, CGB took possession of the plant and was able to get it back up and running in a matter of months. This was no small task as the facility had to be repaired, cleaned, tested, inspected and certified after being unused for a period of time. Once the plant was cleared for production, CGB discovered it wasn't operating at capacity. It was producing 37 million gallons/year and its capacity was 50 million gallons/year. The team knew they had to increase the plant's efficiency and productivity across the board to make the plant sustainable and profitable in the long term.

"Our goal is to enhance the local economy and community by working every day to improve our plant and our process to be part of the solution to our energy needs in the United States," said Mitch Miller, CEO, Carbon Green BioEnergy, LLC.

The plant was originally built with an APACS+ process control system that was reaching its end of life from a service and support standpoint. CGB had to either keep the existing system as is, stock up on spare parts and hope for the best, replace the entire process control system and hardware or take a hybrid approach. The hybrid approach is the one that CGB chose. It enabled them to upgrade their process control platform and interfaces, while keeping existing automation equipment, hardware and I/O intact. This option would allow CGB to continue to have the latest software and support while using its relatively "new" and existing hardware and I/O.

Automation Solution

CG1409 GreenBioEnergyPlant2CGB chose to migrate to a Siemens PCS 7 APACS+ OS for HMI graphics screens and a client/server architecture while using the existing APACS+ control system. The HMI upgrade enabled them to extend the life in their installed APACS+ control system assets with little disruption to production. CGB didn't need to make changes to their APACS+ project configuration or field I/O hardware which reduced testing, outage time and cost. They also ran the former HMI system and the new system (PCS 7 APACS+ OS) side-by-side for three months.  Once they were confident the system was performing as designed, they fully transitioned to PCS 7 during a scheduled two-day plant shutdown.

Additionally, Siemens supplied many of the NEMA motors that power the pumps and processes within the plant and are connected to the PCS 7 to ensure the upmost in uptime and energy efficient operations. According to Edward Thomas, plant manager "The Siemens system helps our staff with troubleshooting and operational consistency and efficiency. The staff really likes that. They also like that it's quicker and there's no lag in the control system. It's pretty bulletproof."

Trident Automation Inc., Kaukauna, Wisc., a Siemens PCS 7 solution partner and biofuels industry expert was responsible for the successful migration and system integration. Trident installed the original system so they were familiar with its features and functionality and were instrumental in making the migration seamless. They also helped to effectively and quickly train the operators on the new enhancements available in the PCS 7 APACS+ OS system.


CG1409 GreenBioEnergyLabCarbon Green BioEnergy has increased its production from 37 million gallons/year in 2009 to 55 million gallons/year today—and the company intends to increase production to 60 million gallons/year by 2015.   As a result of the PCS 7 migration, the company has recognized additional benefits including:

  • Enhanced Trending and Data Analysis makes it easy for operators and the process/management team to manage production and troubleshoot the system.
  • Alarm Management Tools help to identify issues more accurately and improve production.
  • The Historian Tool has improved the ability to fine tune the process and improve consistency and energy efficiency.

According to CEO, Mitch Miller, "Since we've installed the PCS 7, we've been able to more quickly debottleneck the facility and improve energy efficiency. Basically we've been able to take the waves out of the process and it has enhanced the controllability and reliability of the digital control system."

CG1409 GreenBioEnergyPanelsWith the plant running optimally, CGB is supporting 450 local farmers, most within 50 miles of the plant, by purchasing 18 million bushels of corn annually at a market value of more than $100 million. This helps the local agricultural community have a stable buyer at fair market price. Growing corn in the area is profitable again and this is good news for the community.

Additionally, CGB has launched its YellowHose.com campaign advertising $1 less/gallon at the pump by targeting FlexFuel vehicle owners and guiding them to E85 stations.  In 2011, CGB began blending ethanol and natural gas to make E85 on site and is sending it directly to fueling stations.  By blending its own fuel, the company is able to offer its product at $1 less than a gallon of regular gasoline and began selling 50,000 gallons a month. Today that number continues to grow with more than 50 local stations buying more than 500,000 gallons a month (June 2014).

Mitch Miller is optimistic about the availability of higher blend ethanol options in Michigan. "There are currently 218 pumps in the state with higher-level blends and that number needs to be a thousand." To contribute to that goal, Mitch mentioned future plans to expand the plant to produce another 5 million gallons per year by 2015 and to potentially integrate a renewable power source to make them even more energy efficient.

How Sustainable is Ethanol Production?

CG1409 GreenBioEnergyMotorsZero Waste at CGB—Ethanol Production Creates Food & Fuel

  • 100% of the corn's starch is used for ethanol production.
    o    Plant produces enough ethanol (E85) blend to fuel a 2012 Chevy Malibu for 1B miles.
  • 100% of the corn's protein, fat and fiber is made into distillers dried grain which is a highly nutritious livestock feed.
    o    Plant produces enough distillers dried grain annually to feed cattle that feed 2.2M people.
  • Plant uses brewery waste from nearby Beer City USA (Grand Rapids, Mich.) to create ethanol and distillers dried grain.
  • Uses only corn from local farmers (most within 50 miles)
  • CGBE uses waste heat from the distillers dried grain drying process to make steam for the plant
  • With tighter process controls CGB has increased ethanol production while maintaining its water consumption.
  • Energy ROI—2.82 (In 2014, CGB's energy return on investment is 2.82 BTUs output for each BTU input)

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