Report on the Field Demonstration of Battery-Powered Excavators
Kajima Corporation:
Tobu Railway Isesaki Line Elevation Construction near Tokyo Skytree Station
Hitachi Construction Machinery conducted a field demonstration of electric construction machinery in collaboration with Kajima Corporation. The goal was to operate Hitachi’s battery-powered excavator at a construction site in Tokyo to gain essential know-how for using electric construction machinery and to identify any unknown challenges. We spoke with Mr. Takafumi Matsumoto of Kajima Corporation, responsible for construction management at the site, about his evaluation and the challenges encountered after actually operating the battery-powered excavator.
Hitachi Construction Machinery’s battery-powered excavator was introduced for field demonstrations to remove ballast (crushed stone for the roadbed) from the relocated track bed resulting from the elevation construction.
The photo shows the 8-ton class ZE85 battery-powered excavator. A 13-ton class ZE135 excavator was also used for the demonstration.
| Project Overview and Battery-Powered Excavator Field Demonstration Summary |
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| Project Name | Civil Engineering Works for the Elevation Construction near Tokyo Skytree Station on the Tobu Railway Isesaki Line (Section I) |
| Client | Tobu Railway Co., Ltd. |
| Contractor | Kajima - Tobu Yachida - Totetsu Joint Venture |
| Demonstration Period | June 9, 2025 – June 17, 2025 |
| Demonstration Purpose | Operating time prediction, proposals for the timing/equipment of charging, measurement of CO2 emission reduction effects, etc. |
| Construction Machinery Introduced | ZE85 and ZE135 |
Expected Contribution to Reducing CO2 Emissions at Construction Sites
Highly Rated for Performance and Operability — Advance Charging Planning is Key
Takafumi Matsumoto
Construction Manager
Tokyo Skytree Station Elevation Construction Section I
JV Construction Office
Kajima - Tobu Yachida - Totetsu Joint Venture
Kajima Corporation has set the goal of achieving net-zero CO2 emissions across its entire supply chain by FY2050, as well as switching to sustainable alternatives for all procured materials. As part of this effort, the company is working to reduce CO2 emissions at construction sites.
One such initiative is the electrification of construction machinery. This time, in collaboration with Hitachi Construction Machinery, which is connected to our Environmental Headquarters, we introduced two battery-powered excavators for a field demonstration. Our goal was to evaluate not only the performance and operability of the battery-powered excavators compared to engine-powered hydraulic excavators, but also to verify their actual operating time and the usability of their charging equipment through hands-on use.
I have primarily been responsible for construction management at civil engineering sites, but I had never worked with electric construction machinery before. When the battery-powered excavator was delivered to the site, my first impression was, “Wow, that’s huge.” It probably looked larger than engine-powered hydraulic excavators in the same class because it was equipped with a battery.
Then, I noticed the drive noise. Since it has an electric motor, the sound it made was incredibly quiet. Both the site staff and the workers were seeing a battery-powered excavator for the first time, so they were all very curious. They were especially impressed by how quiet it was.
Performance is Satisfactory, Plus the Benefits of Battery Power
We had already confirmed the specifications and functions of the battery-powered excavator at the field demonstration. When we operated it, we found its performance to be equivalent to that of conventional engine-powered machines. The difference lies in operational aspects, such as operating time and charging time. Compared to engine-powered machines, the battery-powered excavator has a shorter operating time. Therefore, even if it is fully charged before work, it requires recharging during breaks.
We used the lunch break to charge the equipment at this site, but since the cable connecting the charging equipment to the battery-powered excavator has limited length, we had to move the excavator close to the charging equipment. If the area near the charging equipment is being excavated, we can’t get close. Therefore, we have to be careful about the daily excavation schedule. Since this was not a large site, it wasn’t too much of an issue. However, on larger sites, careful planning may be required regarding the placement and number of charging equipment units, as well as work procedures.
In terms of performance and usability, battery-powered excavators are high-performing pieces of construction machinery. They are quiet, produce no exhaust emissions, and are popular with operators. Their ability to work in residential areas and tight spaces in urban areas is a significant advantage. On the other hand, challenges have emerged regarding operational aspects, such as operating time and the timing/method of charging. Fortunately, we are receiving proactive proposals and support from Hitachi Construction Machinery, and we are collaborating to identify optimal operational methods.
Reducing CO2 emissions at construction sites is one of the challenges facing the construction industry. However, the solution is not limited to introducing electric construction machinery. For instance, our company has begun testing carbon-neutral fuels, such as RD fuel. Furthermore, it is essential to focus not only on the construction machinery itself, but also on improving work efficiency and productivity. We expect construction machinery manufacturers to provide us with solutions from these various perspectives.
| Operator’s Voice |
Chihiro, Co., Ltd.
This was my first time operating a battery-powered excavator. I thought it might feel different from conventional engine-powered machines, but the controls felt the same. It has plenty of power, and the movements are smoother. Another notable feature is how quiet it is. Even when operating from the cab, you can hear sounds outside the vehicle. You can clearly hear the voices of other operators, too. Since you can talk without raising your voice, I think the low noise level is important for site safety.
REMCO. Co. Ltd.
As you might expect, riding in a battery-powered excavator, you immediately notice the absence of exhaust emissions. You also won’t feel heat building up inside the cabin. This is obviously good for the environment, and it’s ideal for indoor work. It’s not awkward to operate. In fact, I was surprised by how light and smooth the lever is. This time, we charged it during our lunch break, so we had to go back to the charging equipment by then. We’ll need to adjust the morning work schedule accordingly.
Hitachi Construction Machinery’s Road to 2050 
