Advanced Structural Technology (AST) in Oxnard, California, an industry leading manufacturer of forged and spin/flow formed products for the automotive, defense, aerospace and alternative energy markets, approached MJC Engineering (MJC) to replace a spindle-drive on an existing machine. Carl Lorentzen, president of MJC, noticed the aging and outdated Hydraulic Power Unit (HPU) powering the machine. The unit was a conventional 75 kilowatt power pack that was a 30-plus years old unit. Lorentzen recommended a new technology using Variable Speed Drive equipped HPU by his recently established company, Green Hydraulic Power, Inc. (GHP).

MJC is a custom machine tool builder in Huntington Beach, California, specializing in metal-spinning machines for such applications as sheet spinning, flow forming, wheel spinning and rotary forging. The company’s machines are found worldwide, producing end products such as car wheels, aircraft engine housings, spacecraft fuel tanks, seamless gas cylinders and more. MJC machines typically utilize very large volumes of hydraulic power in operation.

MJC created a turnkey solution that includes system integration, engineering, software technology, and programming under the Green Hydraulic Power (GHP) label. The system incorporates a variable speed drive powering an internal-gear hydraulic pump. GHP claims up to 80 percent energy savings over conventional hydraulic systems, as well as noise reduction by 20 dBA, less heat generation, lower cooling requirements, less oil volume, and a smaller footprint.

AST expressed an interest in having a new system quoted. GHP proceeded with configuring a new power pack downsizing the motor from 75 kilowatt to 45 kilowatt. Pumps and motors in conventional hydraulic power units often are oversized to meet maximum duty-cycle demands. By contrast, a variable-frequency drive or servo drive can manage an electric motor’s operating torque and speed more efficiently. Instead of running continuously at full speed, the motor rotates only fast enough to meet system demand at any given time.

The proposal was accepted by AST and GHP proceeded to build the new HPU.

An Established Solution

Soren Rasmussen of GHP had been working with Southern California Edison (SCE) to establish a solution code for this technology.

“The AST unit was our opportunity to have SCE compare conventional HPUs with VSD equipped HPUs,” said Rasmussen. “We worked with the Department for Emerging Technologies at SCE and they agreed to perform an energy audit at AST to establish if GHPs energy saving prediction was true.”

SCE installed equipment on the existing conventional HPU leaving it on for two months to collect as much data as possible, and to better understand the exact duty cycle of the material handling. As soon as SCE completed the energy audit on the existing machine, GHP initiated installation of the new Hydraulic Power Unit.

Exceeding Expectations

GHP had been given a three-day window for installation to insure minimal production downtime.

“Production downtime is a big concern in manufacturing,” said Rasmussen. “We were able to complete the installation and implementation in one day exceeding everyone’s expectations.”

After a successful installation, SCE was contacted to initiate the energy audit on the new HPU by GHP. Another two months of data collecting passed, and the onsite energy audit was complete. Next, SCE compared all the before and after data making sure that each sequence of material handling was identically measured. These results surpassed expectations with energy savings of 78 percent. An actual summary from SCE reveals savings far beyond what had been expected.

“One big factor in saving energy for this client is the peak penalty fee,” adds Rasmussen. “By lowering the peak energy use considerably paired with a large energy use reduction, the monthly energy saving was $4,288.00, and the ROI for this unit was 11 months.”

Positive Impact

Based on the AST energy audit, SCE has initiated incentive programs that financially assist manufacturing facilities to invest in this technology. Green Hydraulic Power, Inc. will pursue other power utility companies now that Edison has provided a solution code. By bringing more awareness to this emerging technology, the hope is, as one power utility company validates the technology, the rest will follow.

“The solution code is the third-party validation we have been looking for,” says Rasmussen. “Southern California Edison customers now have a tested and proven energy saving solution.”

The GHP line is available in two styles: one with a VFD asynchronous motor and internal gear pump, and the other with a servo inverter, synchronous servo motor, and internal gear pump.

Currently, machines with this Green Hydraulic unit are in operation at such industry giants as Meritor, SpaceX, Worthington and multiple plants of GKN Aerospace. All have been in use for more than two years without performance issues.

Owing to the widely varying duty cycles involved, Lorentzen states, “We can say with high certainty our customers are experiencing up to 80 percent energy savings, plus the quieter operation and reduced carbon footprint as additional positives. I’m certainly glad I read what others were doing with servo-pump technology, as it’s made a big and very positive impact on our company.”

Southern California Edison customers can find out more about the Drive Controlled Variable Speed Hydraulic Power Unit solution code by visiting


  • Rob Melsness, CEO of AST
    “We plan on acquiring GHPs for all future HPU system replacements when incentive plans are made available by Southern California Edison.”
  • Soren Rasmussen of Green Hydraulic Power
    “As with many of GHPs previous installations, we get very excited about the tremendous energy savings but feedback from most of our clients reflects upon the noise reduction when applying VSD technology.”
  • John Stewart of GKN
    “You can operate this new machine without that constant deafening roar of the hydraulic unit. In fact, no hearing protection is necessary while working on or around the equipment. In contrast, the inescapable noise while working on our other machines is quite disappointing now.”
  • Sean Ptazek, Senior Design and Manufacturing Engineer of AST
    “While monitoring the oil temperature we never reconnected the water cooling, testing if GHPs claim that no cooling was necessary for this application. The system was running flawlessly with no overheating.
    However, since plumbing from the cooling towers was readily available, we reconnected just to play it safe.”
  • Paul Delaney of SCEs Emerging Technology Department
    “We are constantly looking for new ways to lower energy consumption, applications for LED lights and HVAC are running low. This technology is a nice addition to the list of Solution Codes available to incentivize our customers to save energy.”

For more information on this story, please contact:

15401 Assembly Lane
Huntington Beach, CA 92649
P: 714-333-7367
Attention: Sean Rasmussen, Managing Director


15401 Assembly Lane
Huntington Beach, CA 92649
P: (714)890-0618
F: (714) 895-3561
Attention: Carl Lorentzen, President