In 2017, after the urging of a manager in its bioprocessing plant in Portland, Ind., POET installed its first steam-powered turbine, a device designed to capture excess steam and convert it into electricity to help power the plant.
Just over two years later, POET recently completed the installation of turbines in a dozen plants across the Midwest.
The project represents more than a capital investment in the future of POET. It represents the kind of in-house innovation that has helped define POET for the past 30-plus years. Like a lot of POET initiatives, the idea originated from a team member, was planned by POET engineers and was built by POET’s own team.
And it was a project designed to find even more efficiencies within each POET plant, to take another step toward sustainability and to do the right thing for the environment.
“This is one of those ideas where you look at it and say, ‘Well, we’re saving money and helping the environment. It’s the right thing to do for the company and it’s also just the right thing to do,” says Charlie Bentzen, Process Engineer at POET.
Bentzen, who worked as an engineer at POET Biorefining – Jewell when they installed the steam turbine there, saw the construction and the on-site team’s reaction firsthand.
“The entire team was excited to get a steam turbine because we were going to be part of creating something that would give us direct payback,” says Bentzen. “It was the kind of thing that told everyone, ‘Hey, we’re always growing. We’re always improving. We’re open to new ideas.’”
And that POET was especially open to new ideas from fellow team members.
“Matt Clamme, Plant Manager at the Portland, Ind. plant, kept looking at capturing this steam and kept challenging us to make this happen,” says Rod Pierson, Senior Vice President and General Manager of POET Design and Construction. “We looked at it again and realized how much this would reduce our carbon intensity. It was a different type of project for us to implement, but it gave us an opportunity to learn and to use this technology in other areas as well.”
As far as the technology goes, POET’s boilers produced medium-pressure steam, which is what the bioprocessing plant requires in its ethanol production process. Engineers then increased the pressure those boilers produced, and routed that high-pressure steam to turn the new turbines, which then spin a shaft that creates electricity through a generator. After it is used to turn those rotors, the steam exits the turbine and is captured and channeled back into the system. The lower-pressure steam is then able to be used for the ethanol-making process.
The actual equipment for one type of turbine used at POET plants — which is housed in a room added next to the existing steam boilers — is approximately the size of a semitrailer.
Those generators produce an average of roughly three megawatts of electricity per plant. That’s enough electricity to power one-half of one bioprocessing facility — or approximately 2,000 houses — for a year.
“Essentially, all we did was increase our working pressure of our existing boilers in order to turn the turbine, and then we still use the same amount of heat energy,” says Bentzen. “We found another way to take energy that was being wasted and use it to create electricity.”
For Chris Dickman, POET’s Biofuels Regulatory Program Manager, the turbine project “made too much sense not to implement. There are so many synergies here,” says Dickman. “We already had equipment generating steam, and we’re simply adding equipment to generate electricity from that steam. We know we have to keep searching for these kinds of advantages.”
At POET Biorefining – Chancellor in Chancellor, S.D., they have taken sustainability a step further. They burn methane captured from the Sioux Falls city landfill in the driers used to make dried distillers grains. Their turbine is powered by a solid fuel boiler that burns 400 tons of wood chips — created from local landscaping waste, waste trees, waste pallets and even discarded target boards from a local ax-throwing company — every day.
“Ethanol is a clean-burning, renewable fuel, and we think it’s important to also use clean renewable fuels as our fuel source to run our facility,” says Rachel Kloos, Plant Manager. “The impact of climate change is really important to POET, and we want to get away from the use of fossil fuels in our facilities.”
Since its founding, POET has continued to search for — and discover — creative and cost-effective ways to use every bit of starch, oil, protein and fiber from every bushel of corn. They produce a product that allows asphalt manufacturers to use more recycled asphalt, making their product less expensive and better for the environment. They refine corn oil into feed additives and biodiesel and industrial lubricants. They convert leftover solids into products ranging from syrups to animal feed. Recently, POET discovered a process to convert corn kernel fiber — that’s essentially the skin on the outside of the kernel — into cellulosic ethanol.
And the continued search for greater energy efficiency inside POET’s bioprocessing plants is nothing new, either.
The steam-to-energy-turbines — and operations like the sharing of heat between processes such as distillation and evaporation — fall into the “Combined Heat and Power” system, one of POET’s Four Key Environmental Stewardship Practices. These four keys are designed to create the smallest possible environmental footprint at each of the company’s facilities.
The other practices include BPX Technology (POET’s patented plant-wide process that converts starch to sugar with enzymes instead of heat); carbon capture (they capture carbon dioxide, a natural byproduct of ethanol production, for use in everything from fire extinguishers to carbonated beverages); and Total Water Recovery (every POET bioprocessing center continuously recycles its water and eliminates liquid discharge).
“Overall, across the company, we’re looking at a general queue of projects that focus on continuous improvement,” says Dickman. “Especially those that have benefits in terms of electrical cost savings and greenhouse gas reduction. The turbine project offered both, so once we were successful in terms of implementation and installation, then it just made sense to keep hammering them out.”
And they did.
Just three months after the completion at the initial plant in Portland, the turbine at the North Manchester, Ind., was up and running. Within two years, POET has installed 14 turbines in 13 plants across five states.
“We’re reducing our use of electricity, reusing our own energy more efficiently, reducing greenhouse gas emissions and cutting down on our carbon footprint,” says Pierson. “It’s everything we’re about.”
Like all of POET’s projects, each success — and even each failure — keeps the team moving toward the ideal of energy self-sustainability. It’s a “reduce, reuse, recycle” attitude that dates back to the opening of POET’s first commercial-scale ethanol plant in Scotland, S.D., in 1987, when the Broin family designed and built and painted most everything themselves. When they needed equipment, they searched out defunct ethanol plants and closed creameries. When they heard the Schlitz Brewery was going out of business, they drove to Milwaukee to buy parts, demonstrating yet again a resourcefulness mindset.
“This is another project that gets us closer to cutting the cord and being completely self-sufficient,” says Dickman. “It’s another step that makes us wonder where all this could eventually lead. Zero electricity input? No reliance on outside energy? This is what we think about. It’s what we do here. We all understand that we can’t be stagnant and we’ve got to always be working to find that next improvement. Sometimes, it’s not the easy thing to do. But it’s the right thing to do.”