December 11, 2020

Solar power generation using the walls of the road?
Shortening the Construction Period with Kaizen

Toyota’s Frontier Research Center is involved in various research projects. Among them is the research of a system that uses solar panel to generate renewable energy. The advantage of this system is that by adding the function of solar panels to a sound barrier on a highway, for example, it enables energy to be produced and consumed locally, even in urban areas where the area available for power generation is small, so it can be supplied to the equipment that needs it. This can be done even when the external power supply is cut off, such as during a disaster.
We covered the “Kaizen” (improvement) process during the installation of the panels during the trial of this system.

  • Project members check the completed solar panel

What is a system that utilizes renewable energy?

Fukunaga:Why is Toyota researching a system that utilizes renewable energy in the first place?

Ito:Toyota aims to realize a sustainable society through mobility. As part of this, we have selected sound barriers as a new location for installing solar panels in urban areas and studied a renewable energy system to reduce enviromental impact.

Project Leader Yuji Ito

Previously, he was responsible for mechanical design of automobile manufacturing equipment and partner robots.
Currently in charge of research on infrastructure systems related to mobility.

Interviewer Daiki Fukunaga

Previously, he was responsible for mechanical design of Toyota’s medical machine “Welwalk”.
Currently in charge of research for the realization of a better mobility society.

Fukunaga:What kind of system is the renewable energy system that uses sound barriers?

Ito:It is the system (fig.1) that installs solar panels in a narrow space such as a sound barrier on a highway and carries out a series of cycles to “creating, storing, and using” renewable energy. This system has the advantage of being able to supply power to machines that require power even when the power supply from the outside is cut off. Generally, solar panels are placed perpendicular to the angle of incidence of sunlight to increase power generation efficiency, but we have confirmed that the solar panels installed vertically on both sides of sound barrier can achieve almost the same power generation efficiency when compared to a ground installation.
In February 2018, the Metropolitan Expressway Co. called for joint research on this system on the road, and Toyota raised its hand and started research, thinking that it was an opportunity to contribute to a sustainable society1.

  • Fig.1 Overall View of the Renewable Energy System on the Road

Fukunaga:In this demonstration experiment, I heard that you developed the solar panels jointly with Obayashi Corporation (Obayashi) that was in charge of the installation work. How did you get started?

Ito:Obayashi, who is in charge of construction, told me that “we are looking for ways to further shorten the construction time because occupying the road for construction will cause inconvenience to customers during that period.” They immediately made a full-scale model of the conventional construction method and showed it to us. However, the workers were struggling with repeatedly adjusting the position of the large solar panels in high places. Therefore, we started working on this issue with Obayashi Corporation to find a way to make the installation easier and quicker, and to reduce the burden on workers and the inconvenience caused by regulations on road users.

Utilizing the monozukuri (manufacturing) power of vehicles even in road construction

Fukunaga:You tried to solve the problem jointly, didn’t you? How did you proceed with Kaizen?

Ito:We applied the Kaizen that Toyota has cultivated on the production line to the installation of solar panels. Since this project involved installing 140 panels (280 meters worth), we thought that a way of safely and efficiently assembling parts on the car production line could be utilized.
First, we took a video of the conventional panel installation work, observed it over and over again, and thoroughly analyzed where there was waste. As a result, we found out that we have to redo the process of moving the panel from the truck bed to the mounting position because the distant crane operator and the operator at the mounting position are coordinating to adjust the position to the millimeter. Therefore, as shown in figure 2, we proposed to Obayashi a machine2 that would stop the panel mounting with a crane and allow the same worker to complete the panel movement and mounting work on a single truck bed.
Obayashi suggested that we should consider the expressways, and we produced a prototype.

  • Fig2. Panel Construction Before and After Kaizen
  • Introduction of Panel Mounting Machine After Kaizen

Fukunaga:You created a machine by combining the strengths of both companies. How was the ease of use of the machine?

Ito:Unfortunately, it didn’t work at first. Therefore, we carefully reviewed the problems including the rigidity of the entire machine and the slippage of the rail pulleys, and dealt with the problems speedily. In addition, about 60 additional Kaizen items were performed to complete the equipment.
Finally, we were able to reduce the installation time per panel from 30 minutes to 4.5 minutes. By Introducing this machine, not only are sevral heavy machines unnecessary for each panel installation, but the work needed for 6 people can be performed by only 3 people. The trouble of adjusting with a crane is also eliminated. Namely, this Kaizen leads to reduction of human load safely.

  • A comment from Construction Supervisor Mr. Takahiro Kanemaru (Obayashi Corporation)

Our Challenge Continues

Fukunaga:It was enlightening to hear the story behind the project to use solar panels as a sound barrier.
Finally, please tell us about your future prospects.

Ito:The renewable energy system is currently undergoing a demonstration experiment at the Tokyo Metropolitan Expressway, and at the end of October next year, we will find out whether the entire system is useful or not.
Toyota will continue to dive into issues that have never been challenged before, in order to create a society where our descendants can live happily in the future, and will work with various people and companies to solve them.

Fukunaga:I learned a lot today. I also would like to apply Kaizen work in various ways. Thank you very much.

Friends who Worked on the Project Together
Related release on Tokyo Metropolitan Expressway (Japanese Only)
Related release on Obayashi Corporation (Japanese Only)