Reducing CO₂ in Car Production: High School Students Investigate Mazda’s Manufacturing Efforts

A simple email sparked a two-day tour at Mazda. When four Hiroshima high school students reached out to learn more about the environmental impact of the car industry, we were eager to welcome them to our Hiroshima Plant, and answer their burning questions about our environmental initiatives.

 

In part two of this series, we follow the students on their tour as we try to answer one of those questions: How does Mazda perceive the impact of cars on the global environment, and what solutions do Mazda propose? From the in-house power plant to the paint shop and assembly lines, the students experience firsthand how Mazda is facing the challenge of achieving carbon neutrality.

Ensuring a Future of Carefree Driving: Reducing CO₂ emissions in the car manufacturing process

After attending Sustainable Brands Tokyo in February 2024, four students from Hiroshima’s AICJ High School became curious about Mazda’s environmental efforts. Yutaka Kawasaki from the Corporate Strategy Division, who met the students at the event, greets the group to continue the tour.

The tour of Mazda’s Head Office had a special meaning for Hiroshima’s AICJ High School student Haruka Takahashi. Inspired by her father, Takahashi is a huge fan of Mazda cars and dreams of one day driving her own sports car. This has inspired her to find a way to reconcile her passion for cars with her concerns about their environmental impact.

“The impact of cars on the environment is twofold,” Takahashi says. “There’re the greenhouse gas emissions when they’re on the road, and the CO₂ released during the manufacturing process. As we all become more aware of our environmental impact, I can’t help but wonder if by the time I get my license and can afford to buy a car, the days of carefree driving will be long gone.”

Haruka Takahashi.

Fellow student Minato Hashimoto echoes Haruka’s concerns, while questioning Mazda’s approach.

“Across the world, everywhere seems to be shifting to electric vehicles, yet Mazda doesn’t appear to be investing much energy into this technology,” says Hashimoto. “But, I’ve also heard that EV battery production emits CO2, so I’m no longer sure which is better. That’s why I’m especially keen to learn more about Mazda’s approach.”

Minato Hashimoto.

The four students visited the Mazda Museum where they learned about Mazda’s 100-year journey to the present, and our environmental initiatives.

Kawasaki kicked off the tour by sharing Mazda’s approach and philosophy for environmental challenges.

“Right now, we’re united as a global community in our goal to achieve carbon neutrality for a sustainable planet,” Kawasaki begins. “For cars, this means shifting from traditional fossil fuels to a clean energy free of CO₂ emissions. Electric cars are one potential solution, but as Takahashi pointed out, a huge amount of the electricity powering these vehicles is generated through fossil fuel power plants—which in turn emit CO₂. In other words, unless we make the electricity carbon neutral, a widespread adoption of electric vehicles will not be enough to completely reduce CO₂.”

Kawasaki continues, “And then there’s the issue of car manufacturing, which also produces a significant amount of CO₂. Everything from the production of steel, plastic, and other raw materials for car components, to assembly and painting consumes substantial amounts of electricity and heat.

 

“We also need to consider the broader picture. Things like transporting vehicles to dealerships, plastic burned when the vehicle is disposed of, all of this adds to the carbon footprint. That’s why it’s so important for us to focus on reducing the environmental impact at every stage: from raw material procurement, manufacturing, and driving, through to disposal and recycling. We call this approach Life Cycle Assessment (LCA), a method for evaluating the whole lifecycle of a vehicle. It's an approach that informs what we do at Mazda.”


Mazda’s LCA approach to carbon neutrality.


The students’ expressions turn serious as they learn about the CO₂ emissions at every stage of car production.

Powering the Plant with Cleaner Energy:Transitioning from coal to carbon-neutral sources at the Energy Center, our in-house power plant

Mazda is implementing various approaches to actively reduce its environmental impact at each stage of a vehicle’s lifecycle.

 

One standout example is the Energy Center: Mazda are the only car manufacturer in Japan to have a large-scale power plant located onsite. The Energy Center produces 80% of the electricity used at the Hiroshima Plant, and Mazda are already considering ways to transition to carbon-neutral fuel alternatives. If successfully implemented, Mazda can make a significant reduction in CO₂ emissions on the production line.

Energy Center at Mazda’s Hiroshima Plant. Mazda’s Hofu Plant in Yamaguchi also has an onsite power plant, generating a significant portion of the electricity required for the plant’s operations. 


Jun Kawano, responsible for operations at Mazda’s Energy Center.


Jun Kawano, responsible for operations at the Energy Center, shares some of their initiatives with the students.

“At Mazda, our goal is to achieve carbon neutrality at all Mazda plants globally by 2035. To make this a reality, we need to move away from coal as a fuel source at the Energy Center. The main contender at this stage is ammonia—a fuel that doesn’t emit CO₂ when burned. We’re currently developing plans for an ammonia-based power plant right here onsite.

“Our aim is to gradually shift away from coal and eventually transition to 100% ammonia-powered energy. It’s not just the fuel. Using the technology and energy-saving knowhow we’ve built over the years from operating thermal power plants, we’ll be able to run these new facilities even more efficiently.

“We’re always looking for ways to streamline our processes,” continues Kawano. “Take something as routine as a daily equipment inspection, for example. We now use drones to check for malfunctions in the smokestacks and boilers, and have installed sensors throughout the facility to monitor wear and tear. This not only improves efficiency but keeps workers out of potentially hazardous situations.”

A drone inspects the Hiroshima Plant.

At the Hiroshima Plant, Mazda is also repurposing the vast amounts of steam produced by the thermal power plant. Steam is piped through to heat buildings, and used in the paint shop as thermal energy to dry the vehicles after they’ve been painted, using resources to their full potential. 

Energy efficiency at Mazda: Coal combustion generates steam to drive turbines for electricity production. The steam is repurposed within the plant, maximizing resource efficiency.

Major Energy Savings Without Sacrificing Paint Finish: Paint shop innovations to reduce energy consumption while maintaining quality

The next stop on the tour was the Ujina Plant. This facility houses production lines for painting and assembly, and is supplied with power and steam from the Energy Center.

The tour begins at the paint line. In addition to reducing energy consumption by repurposing steam in the drying process, Mazda has also been developing painting technologies that improve efficiency without sacrificing finish quality. One example is Mazda’s Aqua-tech Paint System, renowned for its world-class environmental performance. Kosuke Maeda, an employee in the painting process department at Ujina Plant No. 1, explains.

“Mazda’s Aqua-tech Paint System uses a water-based paint that can reduce emissions of VOCs (Volatile Organic Compounds) and CO₂. We launched this system in 2009, and it’s used in our plants worldwide, including here at Ujina.

“In 2024, we introduced a new high-efficiency painting machine. Compared to conventional machines, this new machine significantly reduces both VOCs and CO₂. We’ve begun using it for the clear coat step in the painting process, and plan to gradually expand its use.”

Maeda explains the paint line process to the four students.

Under Maeda’s guidance, the students observe the difference in painting between the conventional machine and the new, more efficient model.

Maeda challenges the students to a quiz.

“When applying the clear coat, both the current machine and the new machine use a robotic arm, but the way the paint is applied is different. Can you tell how?” 

As the other students consider, Hashimoto tentatively steps forward.

“Is it to do with the distance between the paint nozzle and the car body?” ventures Hashimoto. “The standard machine sprays from further away, causing the paint to disperse over a wider area. But the new machine comes in closer for more targeted painting.”

“Correct!” responds Maeda. “With the current model, a lot of paint is wasted as it disperses in the air. This is called ‘overspray’, a term to describe paint that splatters and doesn’t adhere to the intended surface. With the new high-efficiency machine, we’ve improved the air nozzle to reduce overspray, which means using less paint overall. Next question: How can using less paint benefit the environment?”

This time, Takahashi attempts an answer. “Is it because using less paint means you can produce less, leading to a reduction of CO₂ in the paint manufacturing process?”

“That’s certainly one advantage,” says Maeda, “but there’s a much more significant benefit. Paint particles floating in the air not only represent inefficiency, but are also harmful to human health, and can cause various other problems too. That’s why we need to continuously ventilate with ceiling fans: We have to keep clearing the air to prevent paint particles collecting in the booth. As you can imagine, this requires a lot of energy. By reducing the amount of paint particles in the air, we can reduce the volume of air we need to circulate. This leads to a lower power consumption and significant energy saving.”

In addition to an improved robotic arm air nozzle, technology was also developed to control static electricity, reducing the risk of sparks even when the nozzle is positioned closer to the vehicle and allowing for safer operation.

Since introducing the new machine, paint usage has been reduced by 17%. VOC emissions have also been successfully reduced by 17%. As Mazda extends this technology to steps beyond clear coating, we envisage even greater reductions, and with the booth ventilation burden also lessened, we anticipate a significant drop in CO₂ emissions.

At Mazda, we’re continuing to explore ways to make the paint line even more energy efficient. Small actions like this add up to big impact, and are paving the way towards our goal of achieving carbon neutrality across all Mazda plants globally by 2035.

Mazda’s exceptional paint finish is due to a meticulous attention to detail in painting technology and technique. Mazda continues to value the expertise of master painters, and even today a part of the painting process is completed by hand.


The students watch the painting process and share their impressions.

Small Actions for Big Impact: Making major gains in efficiency and energy consumption from minor changes in assembly and final inspection

The last stop on the tour was the plant for assembly and final inspection, at the Ujina Plant No. 2 (U2 Plant). Here, components are attached to the painted car body to transform it into the finished vehicle. After assembly, the vehicles move directly to final inspection. If no issues are found, the car is officially signed off as complete.

When it comes to incorporating energy-saving techniques and improving work efficiency, this plant is no exception. U2 Plant manager, Takashi Morihara, talks through some of the initiatives with the students.

“At Mazda plants, we manufacture different types of cars on a single production line. In other words, with different car models coming down the same line, we need to quickly and accurately assemble the necessary parts for each model.

“But relying solely on an individual employee’s judgement on which parts to use can inevitably lead to mistakes. That’s why at Mazda we use a kit supply system. We pre-select the parts for each car and place them in a box which travels alongside the car being assembled on an automated guided vehicle.”

Morihara describes the role of the plant used for assembly and final inspection.

But improvements at the plant are not only through large-scale changes to production methods and systems. The plant has also implemented many clever little innovations proposed by the employees.

Morihara explains, “We have around 400 employees working at the U2 Plant. Each employee is encouraged to consider how they can improve the workflow to reduce errors, and work more efficiently with less effort. We call this mindset, karakuri kaizen

“A great example of a karakuri kaizen innovation is the ‘Quick Quota Counter.’ Let’s say a job requires five nuts. Even for skilled workers, it’s hard to quickly and accurately pick out the exact number of nuts from a pile. But with the Quick Quota Counter, you simply push a lever and the required number of bolts falls into your hand. It’s made a huge impact on efficiency and accuracy.”

The Quick Quota Counter. Moving the lever dispenses the right number of parts. It was invented by an employee who had been working at Mazda for eleven years.

Morihara continues, “At the assembly plant, we use over 700,000 nuts and bolts a day. When you add that up, it’s a lot of time spent counting. That’s why small changes like this can have such a big impact. The Quick Quota Counter is just one example. We’ve made improvements to almost every process.” 

‘Cat’s Hand’ is another example of a karakuri kaizen innovation. The name is based on the Japanese proverb, “I’d even borrow a cat’s paw,” used when you’re so busy, you’d appreciate the help of anyone, even a cat.

Employees not only propose the ideas for karakuri kaizen innovations, they also design, test and refine until these innovations work as intended.

Taken individually, these innovations appear as only minor improvements. However, viewed as a whole, the impact on efficiency is substantial. Karakuri kaizen innovations are also notable for being low-tech solutions, contributing further to the overall energy efficiency of the factory.

“There are around 1,000 processes involved in the assembly of a single car,” says Morihara. “Imagine the combined impact of shortening each process by just one second, or the cost by one yen. When you add that up, it leads to a big increase in productivity, and huge savings in energy. That’s why we keep looking for ways to shave off even one second from the process.”

Once assembly is complete, the vehicle moves on to final inspection where it undergoes various quality checks including inspections of body panels under bright lights, and driving to check performance.

Carbon-Neutral Car Lifecycle

To achieve carbon neutrality as a car manufacturer, CO₂ emissions must be reduced at each stage of the car’s lifecycle. In this part of the tour, the focus was on the most important stage of that cycle: the manufacturing process. After the tour, the students shared their impressions.

“At first I thought that Mazda lacked environmental awareness, because they didn’t seem to be actively involved in electric vehicle production,” shares Hashimoto. “But now I understand that for Mazda, electric vehicles are only part of the solution. Learning about LCA and all the different ways Mazda is approaching the issue has left me feeling a lot more reassured.”

Takahashi adds, “It was quite unnerving to learn about the true impact of production on the environment, not just car manufacturing but industry in general. At the same time, I was encouraged by how many different initiatives Mazda has put in place, and I’m feeling more hopeful about the future. If the efforts we’ve seen today bear fruit, they’ll come a future when I can drive a sports car without worrying about the impact, and I hope Mazda continues what they’re doing.”

After the students expressed their renewed impression of Mazda and expectations for future initiatives, Kawasaki closed this part of the tour with these final words. “Just like Takahashi, we at Mazda want a future where people can experience the freedom and joy of mobility in the cars they love. That’s what drives us forward to achieve our goals and why I’m committed to doing what I can to contribute to these initiatives at Mazda.”




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Reducing CO₂ in Car Production: Mazda’s Manufacturing Efforts  

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