For heavy foundation equipment this poses a particular challenge. Vibratory hammers, impact hammers, rotary heads and dredging pumps require high hydraulic power and robust, reliable energy supply. Fully replacing existing diesel-driven fleets with new all-electric tools would be technically possible, but economically unrealistic for most contractors.

Dieseko Group’s Electric Hydraulic Power Unit (EHPU) range is designed as a pragmatic answer to this dilemma. The electric-hydraulic powerpacks provide zero-emission hydraulic power while allowing contractors to continue using their existing hydraulic foundation equipment. In practice this means a contractor can connect an EHPU to the grid or an external battery container and operate the same vibratory hammers that would otherwise be powered by a diesel power pack.

This article outlines why the EHPU range was developed, how the concept has evolved, which problems it solves on site, who it is intended for, how the different models compare, and what the likely future developments will be.

First, regulation.

National and local governments are increasingly defining zero-emission requirements in their tenders, particularly for inner-city and infrastructure works. Large cities introduce or expand zero-emission zones where diesel equipment is heavily restricted or prohibited. Foundation work in these areas can only continue if the equipment complies with strict emission rules.

Second, client demand.

Public and private asset owners have set ambitious sustainability targets. They expect contractors to demonstrate concrete reductions in CO₂ and local emissions, without compromising safety or schedule. In procurement procedures, the ability to carry out works with zero-emission equipment is becoming a differentiator.

Third, the technical reality on site.

Heavy foundation tools require high hydraulic power and long operating hours. A straightforward replacement of diesel powerpacks by machines with integrated batteries would quickly run into limits of energy density, charging times and total cost of ownership. In addition, contractors often own a broad fleet of hydraulic tools with a remaining technical lifetime of decades. Scrapping these tools long before the end of their life is neither economically nor environmentally attractive.

Electric Hydraulic Power Units offer a different route. Instead of electrifying every individual tool, the power generation is electrified. The EHPU supplies oil flow and pressure to the existing hydraulic circuit, but its prime mover is an electric motor rather than a diesel engine. The unit can be supplied from the grid when a sufficiently strong connection is available, or from external battery containers, biogas generators or hydrogen-based power units when grid capacity is limited.

In short, EHPUs enable contractors to work towards zero emissions today, without having to replace their hydraulic fleets overnight.

Technically the concept worked, but the overall system proved complex and expensive. High-end components had long lead times and required specialist knowledge for maintenance. For a market that was still exploring electrification and had only limited zero-emission obligations, the threshold for wider adoption was simply too high.

A few years later Dieseko took a strategic step back and redefined the concept. Instead of focusing on bespoke, high-end solutions for individual customers, the company decided to develop a standardized range of Electric Hydraulic Power Units that would be suitable for rental fleets and a broad group of contractors. The design philosophy was to find a golden mean between performance, cost and serviceability.

The result is the current EHPU range: the 250e, 400e and 700e units based on robust air-cooled asynchronous motors with soft starters, and the larger 1100e high-end solution  based on permanent magnet motors with advanced inverters and liquid cooling. All units share a modular, “block-building” architecture that remains familiar to mechanics used to conventional hydraulic powerpacks.

A notable design choice is that the EHPUs do not contain integrated batteries. Instead they are powered by standardized 400 V AC connections from the grid or from external battery containers and alternative power sources. This keeps the powerpacks compact and avoids tying their lifetime to the rapid innovation cycle of battery technology. It also means that specialist battery suppliers can focus on energy storage, while Dieseko concentrates on delivering reliable hydraulic power.