Volvo Construction Equipment is at the forefront of global efforts toward electrification and non-diesel alternatives for mobile machines, and the company aims to reach net-zero greenhouse gas emissions by 2040. It has offered battery-electric wheel loaders and mini excavators for several years and will soon launch an electric road asphalt compactor and an electric version of its 24-ton EC320 excavator. We asked Dr. Ray Gallant, Vice President Sustainability and Productivity Services, about Volvo CE’s ongoing efforts toward creating a carbon-free future for off-road equipment.
FPW: Many experts agree that a transition to non-traditional machines like battery-electric construction equipment will require technological innovations across the board. How are those efforts progressing?
Ray Gallant: We’re only in the beginning stages of this journey. If you step back and look at what we’re doing, the key to success is going to be energy management — not only on machines, but on work sites. The goal is doing only value-added work and doing it in the most efficient way possible. Getting more out of our hydraulics, more out the machines, more out of every kilowatt is going to be key to making this successful.
With diesel, you can live with an inefficient hydraulic system because nobody notices it. Now, with electrification, it’s a big deal because you need more batteries that you have to carry around all day, and they’re heavy and expensive.
If we are wasteful with the energy, then we’re not going to have the duty cycles we want. We’re not going to have the efficiency and the productivity gains that we envision these technologies could bring to the table. So to me, hydraulics is a critical technology. Hydraulic efficiency advancements, and electrical and powertrain enhancements, are keys to making this work and getting our energy efficiency much, much higher.
FPW: What are you doing to make hydraulic systems more efficient?
Ray Gallant: Of course, we work with our suppliers to pinpoint losses and maximize the efficiency of all the various components. That’s part of our philosophy, partnering with companies that hold the same ideals that we do from a sustainability point of view. Together, we are collaborating to make the entire operation more efficient, more productive, and safer — whether it involves hydraulics, electrics or whatever.
But the secret really is to start looking at a broader viewpoint and how those components can work together in more-efficient systems. For instance, running a larger hydraulic pump at a lower speed saves a lot of fuel because the engine runs more efficiently at lower rpm. The power requirements and the operation of the machine didn’t change, only the volume of the pump. It’s details like that that we must think about.
The other big part of hydraulics is, of course, most of our motions also entail an opposite motion that’s a total waste of energy. An excavator, for instance, requires power to break out and lift a load. But when the boom lowers back down to dig the next bucket load, the machine consumes additional power to keep the boom from slamming down. Why don’t we capture that energy and put it back into the system, rather than restricting flow and wasting that energy. So recuperation and efficiency are the two sides of it.
A few years Volvo introduced a hydraulic hybrid excavator that uses accumulators to capture energy from the swing motion and then feeds it back to supplement the pumps in other cycles. And our engineers recently won the Volvo Innovation Award for an excavator circuit architecture based on common rail hydraulics. Every time a cylinder extends or retracts, it captures energy from the opposite motion and reuses it. There are a lot of efficiency gains there as well. That’s the hydraulic revolution that I’m talking about, advancing our designs and making them a standard part of the machine.
FPW: Do controls advances play a role?
Ray Gallant: There are also a lot of gains to be made thanks to electronics and the electrical architecture. We’ve moved from mechanical linkages to pilot-operated controls and gained some efficiencies. Now we’re going to electrohydraulics. The benefit: electrohydraulics is very efficient and it enables very precise operations and control. Now, instead of operators overshooting a dig a bit and having to pull through too much ground, which wastes time and energy, they’re able to control that motion with high precision.
Then you add in communication technologies, sensing technologies and artificial intelligence, and you have a very precise machine even in the hands of a novice operator who can work with minimal energy losses.
And it’s important to look at the entire work site. We can literally spend millions of dollars to try to get engines to be 1% or 2% more efficient, and maybe never get there. But you can turn around and look at a site and with a minimal investment, get 15%, 20% more efficiency out of it by changing the machines’ work cycles, loading spots, how fast they travel in a transport cycle. All those little things can add up to a lot of gains. We’re really looking at the entire operation, not just an individual machine or operator.
FPW: So to a certain extent, the future success of mobile hydraulics lies in advancing beyond current practices?
Ray Gallant: I think everybody is realizing that as we move to these new technologies, the status quo is not good enough. We’re simply using too much energy. As I said earlier, we’ve been wasteful, we’ve been spoiled by the availability of energy through diesel. It’s relatively cheap, easy to get, plentiful. Now we’re having to really assess how we use that energy and how we can be more efficient.
Hydraulics is a great technology. But rather than relying on a main pump that sends oil all through a machine, perhaps you move to decentralized sources closer to the actuators. Maybe in some cases you go to electric actuators because power transmission is by wire, which eliminates inefficiencies in a hydraulic circuit with all the various lines and connectors. Those are just a few possibilities that we’re looking at for the future.
FPW: A few manufacturers are dabbling with all-electric construction machines with no hydraulics at all. What’s your opinion of this?
Ray Gallant: I think it’s an excellent idea. We built a fully electric prototype small excavator a few years ago. Our feeling is that the technology and components are not yet ready for commercialization. When you look at the machines with no hydraulics, from an efficiency standpoint it’s obviously better, but from a price standpoint it’s way worse right now. But certainly in the concept stage, absolutely, there’s a place for that.
I don’t think we’ll get rid of hydraulics. There are certain applications where electric-actuator technology is just not there. Either it lacks the power needed, doesn’t have the speed of actuation or, even worse, the package size is so large that the operator can’t see past the actuator. There are a lot of considerations going forward.
FPW: Are battery-electric hydraulic machines the ultimate answer?
Ray Gallant: We look at these in terms of the duty cycle and the power required. And what you see very quickly is when you get up above 150 to 200 horsepower and no more than six to eight hours of battery storage, and it’s probably not a good solution. There are two problems. One is to get enough pure density to store that much energy requires a lot of weight, a lot of cost, and a large volume in batteries. But the second problem: charging and discharging demands a long, long cycle. You discharge it over eight hours, but you don’t want to have to park then for six hours or more to recharge. That really tends to drive towards hydrogen or alternative fuels that can be refilled almost as quickly as with diesel.
And we need to be careful when talking about being fossil-free and carbon-neutral. A lot of people jump right away to the conclusion that we’re getting rid of internal combustion. Well, we might get rid of diesel, we won’t get rid of internal combustion. It just may be different fuels that power it. We really need to consider the application.
Again, when you’re looking at these new technologies, there’s no single answer. There are going to be applications where battery electrics work great, there are other applications where no, it’s just not an efficient way to do it. And that’s the exciting part of this going forward. We don’t rule out any technology. Rather, we ask which one works the best in a specific application.
FPW: Is that Volvo’s plan for the future?
Ray Gallant: Yes, we are definitely on parallel paths. We right now have five commercialized battery electric machines, plus the DD25 compactor coming out this year and the EC320 excavator next year, which gets us into larger machines. We’re testing 600-volt batteries and heavier-class machines. We continue to develop a hydrogen fuel-cell prototype. We’ve got grid-connected machines coming out. There’s a whole raft of products. We will continue to commercialize various models using proven technologies as well as maturing other technologies along the way. And these developments need to happen to parallel. You can’t settle on one solution and say, “That’s the answer,” because that answer may only be good for a few applications.
We’re lucky that many applications are covered by internal combustion today. So that gives us time to mature these new technologies to take over. Now, hopefully, the internal combustion will be with low-emission fuels or renewables and not pure diesel, but certainly, we have that transition period on the path ahead.
Volvo Construction Equipment