The Drive Toward Emissions-Free Construction
The construction industry is transforming as sustainability goals and stricter emission regulations push for electrification in off-road machinery. The focus is expanding from electrifying traction systems to work functions such as hydraulics, steering, braking, and auxiliary systems. This shift is driven by urban zero-emissions mandates in cities like London, Berlin, and Paris, with contractors increasingly winning or losing bids based on emissions data.
Performance Demands vs. Battery Limitations
Electrified work functions face unique challenges due to the high-power, continuous-duty requirements of construction equipment. Smaller machines like mini excavators operate efficiently on lithium-ion power, but medium and heavy-duty machines struggle to meet their demands with batteries alone. Current battery technologies are improving, but they still cannot match the power requirements for large equipment that work long hours with substantial hydraulic loads.
Addressing Energy Loss in Hydraulic Systems
Hydraulic systems powered by internal combustion engines (ICEs) are highly inefficient, with less than 15% of fuel energy converted into useful work. The remaining energy is lost to friction, fluid throttling, and component inefficiencies. In contrast, electrified systems can optimize energy use by applying power only when needed, reducing idle losses and extending battery life.
Electrification Solutions: EHPs vs. EHAs
Electric hydraulic pumps (EHPs) are commonly used for electrifying work functions. Early systems used fixed-speed motors to replicate combustion engines, but newer EHPs now use power-on-demand principles and variable-speed motors, offering improved efficiency. Electric hydraulic actuators (EHAs) eliminate the need for central hydraulic circuits, providing greater energy performance, control, and modularity. While more complex and expensive, EHAs are beneficial for many OEMs, especially in hybrid systems that combine EHPs with conventional actuators for a balance of performance and cost.
Thermal Management in Electric Machines
Thermal management is a critical aspect of electrification. Unlike diesel engines, which generate substantial waste heat, electric machines require cooling systems for their batteries, inverters, motors, and controllers. The cooling requirements vary depending on machine type. For example, excavators require two separate cooling loops: one for the drivetrain and another for the hydraulic motor and inverter.
Surface drilling machines, with their tall booms, face additional pressure and control demands for cooling fluid.
Voltage Considerations and Cooling Systems
Cooling systems can be low- or high-voltage, with high-voltage systems offering better efficiency and airflow but requiring specialized cabling and insulation. Low-voltage systems are simpler and less space-consuming but deliver lower performance, making them more suitable for localized applications. Engineers must evaluate each machine's specific cooling needs, size constraints, and safety requirements to determine the best option.
Hydrogen’s Role in Heavy-Duty Equipment
While lithium-ion batteries are suitable for smaller machines, hydrogen is becoming a promising solution for heavy-duty construction equipment. Hydrogen-powered internal combustion engines (ICEs) or fuel cells provide higher energy density than batteries, making them suitable for larger machines with long-duty cycles. Hydrogen fuel cells are already being tested in excavators, forklifts, and articulated haulers. However, the limited hydrogen infrastructure remains a major barrier to widespread adoption, though increasing demand could help drive infrastructure development.
Digitalization and Smart Systems
Alongside hardware advancements, digital technologies are playing a key role in electrifying construction equipment. Modern machines are increasingly equipped with sensors that monitor pressure, torque, temperature, and mechanical stress. These sensors improve machine performance, enable predictive maintenance, and ensure compliance with emerging functional safety standards. For example, steer-by-wire and brake-by-wire technologies replace hydraulic systems with electronic inputs, enhancing control and enabling automation.
Smart Controls for Greater Efficiency
Digital platforms like Parker’s IQAN allow engineers to design and test custom control logic that ensures compliance with safety and performance standards. These platforms also enable cloud diagnostics, which optimize service schedules and reduce downtime. The integration of sensors and digital controls ensures that machines are more efficient, with maintenance driven by actual conditions rather than fixed intervals.
Conclusion: Designing for Sustainability
The future of electrified work functions relies on rethinking machine architecture. Performance gains come from integrating smart controls, optimizing thermal systems, and selecting the right energy sources for each application. Whether through batteries, hydrogen, or hybrid systems, the goal is to create machines that are cleaner, quieter, and more productive, without sacrificing the performance needed in the toughest construction environments.
As electrification continues to evolve, engineers and designers must navigate this complex transition, working with solution providers to build the foundation for cleaner, smarter job sites.
About Parker Hannifin
Parker Hannifin is a global leader in motion and control technologies. For over 100 years, the company has been enabling engineering breakthroughs that lead to a better tomorrow. Learn more at www.parker.com.