• 12/5/2022
  • By Doosan Infracore North America LLC

Doosan DX20ZE-7 Electric Mini Excavator on display at tradeshow.

Electric energy, also known as green energy, is a high priority in many industries, especially construction.

Now an effort is underway for equipment manufacturers to design and produce electric earthmoving equipment, especially mini excavators. In fact, several equipment manufacturers have displayed prototype or pilot machines powered by batteries on the jobsite or at construction equipment trade shows.

While we don’t know for sure when manufacturers will move from diesel to battery power, industry advancements are signaling that the move toward electrification isn’t slowing down anytime soon. New innovations in construction equipment have reduced toxic emissions and the reliance on after-treatment devices.

To explore why electrification in compact construction equipment is gaining momentum, we spoke to Thomas Lee, director of product management at Doosan Infracore North America.

 

What Spurred the Shift to Electric Heavy Equipment?

For many years, the U.S. Environmental Protection Agency has pushed for stricter emissions standards for off-highway (non-road) diesel engines, especially those used in construction equipment, using a tiered approach to reduce emissions.

Tier 4 Final is the most recent standard in North America and limits new diesel engines to near-zero levels for nitrogen oxides and particulate matter. To meet these standards, there has been an effort by manufacturers to design construction equipment with fewer emissions, particularly compact models that are easier to manufacture and power.

Concern for contractor safety is one important reason that manufacturers are developing zero-emission equipment. Since smaller construction equipment is typically used indoors or close to homes or buildings, noise and emissions can be a concern for operators.

Operating a conventional diesel machine in a confined, enclosed space, such as for indoor demolition, can be detrimental to the operator’s health or safety. Instead of putting themselves at potential risk, many choose to use less efficient hand labor instead of machinery.

Electric machines have a great advantage over their diesel counterparts due to less noise and no emissions.

“Compact equipment has a higher tendency to be used in cities and residential areas where it works in close proximity to other equipment and operators,” says Lee.

“Running a machine with green energy or zero emissions can help operators maintain their typical work practices without worrying about their health or safety. With the global trend toward carbon neutrality and considering the tremendous growth of the electric vehicle industry, we can also expect high growth in electrified construction equipment.”

 

What Electric Advancements Do Manufacturers Need To Adopt?

The goal of construction equipment manufacturers is to build productive and efficient machines. In the next five to 10 years, it will be possible for customers to choose between a diesel and an electric-powered mini or compact excavator.

“We foresee a faster shift to electrification as battery technology develops and lower costs are driven by mass production,” Lee says. “Within the last 20 years, technology has made advancements when it comes to electric machines. Most of the current electrified excavators are electric/hydraulic machines.”

To make the shift to electric worthwhile, the machine needs to be as similar to its diesel counterpart as possible, specifically when it comes to performance features like lift capacity, breakout force and swing torque. However, electric machines have clear differences.

“These machines have a battery pack and electric motor instead of a fuel tank and diesel engine,” Lee says. “On all-electric machines, the hydraulic cylinders are replaced with electric actuators, eliminating the need for hydraulic components.”

Since electric machines are smaller and have relatively light duty cycle requirements, many can take on a typical eight-hour workday when equipped with a lithium-ion battery (less than 50 kWh) and electric motor (less than 20 kW).

Maintenance and performance are other considerations for manufacturers.

“The simplified design of electric and hybrid machines is appealing because maintenance costs tend to be lower,” Lee says.

 

What Are the Next Steps for Electric Construction Equipment?

There are many potential advantages for electric-powered construction equipment, such as operator safety and fuel savings, as well as maintenance and performance improvements. However, there are still issues to address before widespread adoption on jobsites, including the need for charging facilities.

“Charging facilities with a stable source of power need to be close to the jobsite,” Lee says. “Fast-charging, plugless power charging technologies developed by the electric vehicle industry can also make an impact on the construction equipment industry.”

Other considerations are the battery size and the costs associated with electric machines.

“One of the focus areas is to find a sweet spot for the battery capacity, as it has a major influence over the machine uptime,” Lee says.

“Designing a battery pack and deciding the capacity were the most important steps of producing an electrified mini excavator. Electrified machines have a higher initial price due to the excessive cost of the battery pack. Government support is critical to the long-term success of electric compact equipment.”

There is much potential for electric power and electric innovation in compact equipment, which will likely carry through to larger earthmoving machines as the technology advances.

 

What Is Doosan Doing To Move Toward Electric Power?

Doosan displayed its first electric-powered mini excavator at CONEXPO-CON/AGG in 2020, and has continued refining the design and technology. The next iteration — the new DX20ZE-7 mini excavator — will be the company’s second electric-powered compact excavator and will be displayed at CONEXPO in 2023.

Looking into the future, Doosan has announced plans to offer up to four electric-powered mini excavators in North America by Q2 2024. These electric models will complement the company’s diesel-powered mini excavators, and both configurations will be offered for dealers and customers in the United States and Canada.

No matter where the industry goes, innovation is rapid and there are many possibilities for electric power and electric innovation in construction equipment.

We foresee a faster shift to electrification as battery technology develops and lower costs are driven by mass production,” Lee says. “Within the last 20 years, technology has made advancements when it comes to electric machines. Most of the current electrified excavators are electric/hydraulic machines. "
Thomas Lee, director of product management at Doosan Infracore North America