Reducing your carbon footprint. It can be a worrisome thought. For the heat-intensive metalcasting industry, the pressure to change how the foundry creates, consumes, and discharges heat is slightly reminiscent of the famous 1977 “Star Wars” trash compactor scene. Walls slowly closing in, no way out, try not to panic, and then, wait, there’s a tentacle-waving slime monster in there, too? 

Yes, the heat is on—both from customers demanding sustainability from their suppliers, and eventually from government regulation—but the situation is far from hopeless, and far, far less desperate than the cinematic machinations of George Lucas. In fact, some proactive foundries have already faced the “monster” and disarmed the threat of the unknown by mapping realistic goals and achieving big wins in energy efficiencies.

The decarbonization of the industrial sector is the object of increasing scrutiny, but sustainably-generated electrification and elimination of carbon production won’t happen overnight—there’s simply too great a dependence on the combustion of fossil fuel, which releases carbon dioxide into the atmosphere. In 2018, 100 quadrillion (15 zeros) BTUs were consumed in the U.S., and 81% of the energy sources comprised the burning of petroleum, natural gas, and coal. The industrial sector used slightly more than one-quarter of the total energy consumption, and transportation took another 28%. 

What will bring meaningful benefit to the foundry in its pursuit of carbon reduction is energy efficiency, according to Mike Stowe, senior energy engineer at Advanced Energy. In other words, making more with less is strategically essential. 

“Energy adds value to your product—you’ve paid for all that natural gas and electricity, and you bring it into your process, whether it’s melting or casting or machining or some other type of process, but you want to reduce energy loss as much as possible,” Stowe said. “There always will be losses, you can’t have it 100% perfect, but you want to get as close as possible. And managing your energy consumption is one of the best ways to manage your carbon because you consume electricity or you burn natural gas or propane or fuel oil—that’s impacting your carbon footprint. If you become more efficient and reduce that energy from losses, you have a lower carbon footprint.” 

Understanding ‘Scopes’

According to the “Inventory of U.S. Greenhouse Gas Emissions and Sinks 1920–2020,” over three-fourths of greenhouse gases are emitted from carbon dioxide directly from combustion; in the foundry, that’s from furnaces, ovens, cupolas, and anything that’s burning coke or natural gas, for example. Currently, electricity generation is a huge source of carbon, he said, because both coal and natural gas are burned to make electricity. The power generation industry is responsible for creating one-fourth of the country’s greenhouse gas emissions. 

When it comes to evaluating the foundry’s own carbon footprint, the big picture of emissions has to be considered, not just the CO2 coming straight from the foundry’s own physical production processes. To fully understand one’s contribution to the carbon emissions problem, the totality of emissions sources has to be appreciated. Hence the term “scope” is employed to recognize all the sources of CO2 emissions tied to one’s own production. See the illustration above. 

• Scope 1 Emissions––come directed from company activity, such as fuel combustion.

• Scope 2 Emissions––are driven by what a factory consumes, like CO2 from electricity that’s generated offsite but used onsite.

• Scope 3 Emissions––includes other emissions embedded in raw materials, logistics, or waste management. 

Before getting lost in the weeds of evaluation and CO2-reduction planning, foundry management can turn to a range of readily available resources including AFS’s partnership with APPI Energy to provide free consulting and guidance; the ISO body of standards and ISO 50001 certification; and U.S. DOE and EPA, which provide free resources to help companies understand their carbon, energy efficiency, and relevant technology.

Foundry Journey No. 1

AFS Corporate Member Dotson Iron Castings in Mankato, Minnesota, has kept its entry into decarbonization fairly simple with a project-by-project approach. The ductile iron, green sand foundry produces medium-volume castings in the 2- to 50-lb. range and uses electric induction melt while also focusing on green sand reclamation to core sand from both its own facilities and from other foundries. 

“We don’t have specific carbon reduction goals; rather, our overall is to get more efficient, and as we get more efficient, carbon [reduction] will come along for the ride,” said Eric Nelson, vice president at Dotson.

Ten years ago, the company joined a Minnesota program jointly funded by electric and natural gas suppliers and became a Process Efficiency Program Customer, which helped the foundry establish an energy baseline, identify improvement projects, evaluate results, and earn rebates, which then fund the next project. For larger, more significant projects where additional data is needed, the program has funded additional research at Dotson. 

Between 2012 and 2022, Dotson tackled key projects and realized major energy efficiencies: 

1) The foundry changed its melt system, which reduced electricity consumption by 14%. (Peripheral projects that yielded significant electricity reduction included changing processes for compressed air, lighting, and HVAC.) 

2) Dotson was able to use the waste heat from its induction furnaces to achieve a 49% reduction in its natural gas consumption––it heats about 5 million BTUs per hour at its facility. Part of the savings also came from reclaiming waste heat to: heat the plant in winter, dry its scrap metal, and become makeup air. 

3) A resource-saving initiative unrelated to energy but of great importance nonetheless resulted in a 72% reduction in water consumption. Dotson achieved the milestone by switching from evaporative coolers to adiabatic coolers. While efficient, evaporative cooling towers require significant amounts of water. A simple change yielded substantial improvement. 

4) For Scope 2 impact, Dotson reduced 150 loads of incoming sand and bond material per year by implementing a reclamation process. Upstream activities of trucking and mining are therefore decreased, and material that formerly went to landfills as cover or to a cement plant as feedstock now remains in-house as reusable, recycled products.  

Foundry Journey No. 2

For AFS Corporate Member Waupaca Foundry, headquartered in Waupaca, Wisconsin, energy efficiency is viewed as a strategic maneuver to remain a strong, agile competitor. The company operates four facilities: Plant 1 in Waupaca, with 600 employees, pours 250,000 tons of gray iron per year; Plant 2/3 also in Waupaca, with 900 employees, pours 470,000 tons of gray iron per year; Plant 4 in Marinette, Wisconsin, with 750 employees, pours 200,000 tons of ductile iron per year; and Plant 5 in Tell City, Indiana, with 1,000 employees, pours both gray and ductile iron totaling 450,000 tons per year. 

In 2004, the company became intentional about making energy improvements on a project-to-project basis, addressing air compressors, improving lighting, and installing high-efficiency motors, much of which was off-the-shelf technology, said Bryant Esch, director of environmental engineering at Waupaca Foundry. Capitalizing and implementing made for a challenging six years, he added, but by 2010 Waupaca was ready to go to the next level and entered a voluntary Department of Energy program called the Save Energy Now Leader Program, which is today known as the Better Plants initiative. The gist of the commitment is to reduce energy intensity by 25% over a 10-year period, and in 2020, Waupaca was nearly there with 23.5%—though they hit a 6-point setback during the pandemic.

A natural byproduct of Waupaca’s focus on reducing energy consumption is the coinciding benefit of cutting CO2 emissions. It hasn’t come easily; however, while encountering many struggles to complete larger and more complex projects, the company has found that each has paid off.

“If you can get engineering to put together a justification so management can see what the potential will be, I think you’ll find that these energy efficiency products will stand up very competitively with other capital improvement projects in the foundry,” said Esch.  

To maintain both its course and pace, Waupaca Foundry eventually formalized the management of its sustainability initiatives. 

“Like many foundries, we were already doing quality management— we had ISO 14001 Environmental Management,” said Esch. “Then one day we had an epiphany: Energy management fits right into ISO 14001, so we started doing it that way. Eventually that evolved to 50001, and today we do have one facility that’s certified ISO 50001, and we’re working on rolling the others out, too. It has been very helpful to get energy management more business integrated.
Esch summarized three key initiatives Waupaca Foundry has achieved:

1) Waste Heat Recovery System—A closed-loop heat recovery system provides building heat during winter and hot water year-round. Since December 2008, Plant 1 has used the heat from its cupola iron-melting process to provide 70% of the plant’s space heating requirements.

Project Benefit: Helps to offset annual heating costs. Reduces 4,600 metric tons of carbon dioxide emissions annually.

2) Cupola Blast Air Dehumidification System—A cupola dehumidification system to reduce the introduction of humidity to the cupola blast air during summer months and year-round.

The project involved installation of two dehumidification systems (Plant 2 and 5) comprised of desiccant wheels reactivated with cupola waste heat to provide a steady supply of dry blast air.

Project Benefit: Reduction of coke demand by 2.5% and associated emissions of 4,900 tons of carbon dioxide annually.

3) Industrial Carbon Capture—The company is in the process of determining the feasibility of fast-growing cyanobacteria (microalgae) to capture carbon emissions for conversion to fuels and beneficial co-products. They have installed pilot growth units to capture melting process carbon emissions for algal biomass production. Waupaca Foundry cupola emissions and WWTP media were utilized to test the growth and yield of the fastest-growing microalgae on earth (with less than four-hour doubling times). Project Benefit: Trial and advance cutting-edge carbon sequestration technology.

Less Carbon, More Customers?

The 800-lb. gorilla in the room is the question of whether lowering the foundry’s carbon footprint will result in acquiring and/or retaining more business. Sources confirm the answer is a resounding “yes.”

Bob Baird, energy sustainment manager at General Motors, says his company and the auto manufacturing sector in general is promoting reductions in CO2 in the products they buy. GM asks its suppliers to prove they have low-carbon initiatives in place. Similarly, Jeff Krause, director of EHS at HA International, reports their largest U.S. customer recently communicated a new requirement, which he described as: “You are going to put in an entire corporate social responsibility program and make firm carbon reduction—and ultimately neutrality commitments globally—or you’re not going to be a qualified supplier to us.” In addition, some companies are going a step further, asking their own suppliers to require evidence of carbon reduction programs from their suppliers, too. 

Esch at Waupaca affirmed the trend that’s appearing up and down the supply chain. And yet, while many are trying to demonstrate their supply base is operating sustainably, some hold back on CO2-reducing innovations for an age-old reason.

“There’s no doubt that there are a lot of requests and pressure coming down right now,” he said. “It seems like we get a lot of questions and interest. In these cases, we may have opportunities that we present to the customer [to reduce carbon in their products]. These decarbonization and energy-reduction initiatives pose a challenge for Waupaca—and presumably any other casting supplier—in managing the carbon reduction targets against the cost.”    

As a whole, sources agree the metalcasting industry should expect an increase in customers and suppliers requiring corporate sustainability documentation. To keep from being a scene from “Star Wars,” the sooner the foundry begins to address energy consumption, their business better off it will be. 

Click here to view the column in the June 2023 Modern Casting digital edition.