By Andrea Watts
In a press release on March 31, 2021, British Columbia-based Mosaic announced their partnership with EcoWest Driven to use Tesla electric semi-trucks on a trial basis, an arrangement billed as the world’s first.
“We are committed to achieving carbon neutrality by 2035, and electrifying our log hauling fleet is a significant step in that direction,” said Jeff Zweig, president and CEO of Mosaic Forest Management. “BC is a global centre [sic] of excellence in forestry, and we are proud to work with our local partner, EcoWest Driven, on this important project.”
What will it take to see electric logging trucks in the U.S.? In 2018, Oregon State University (OSU) professors John Sessions and Kevin Lyons published Harvesting Elevation Potential from Mountain Forests, in the International Journal of Forest Engineering (https://tinyurl.com/295brjp5). Their paper explored the feasibility of using electric logging trucks on a British Columbia haul route that connects the southwest slopes of Blanshard Peak to a sort yard at the junction of the Stave and Fraser rivers.
To explore the real-world application of their research for contractors, following is an interview with Lyons and Sessions edited for length and clarity.
When did you take notice that electric trucks could be an option for the logging industry?
Sessions: Tesla had proposed the release of their heavy truck, what we call a Class 8 truck, in 2017. We started to look at its application in forestry in the Northwest. If electric trucks are going to work anywhere, they have a good chance of working in the mountainous region of the Northwest. The trucks go up the hill empty and once loaded, come down the hill; we can regenerate some of the energy that’s used in braking the vehicle back into the battery for use to go back up the hill. We also have low electricity rates through hydroelectric power, which is renewable.
Was Tesla the first company to explore the use of electric trucks? What about Peterbilt or Mack?
Sessions: Tesla started in passenger vehicles to replace conventional gasoline engine motor vehicles, and then they saw an opening for heavy trucks. But there are other competitors using other options. Tesla uses a battery to store the energy, while the competing powertrains, some which predate Tesla, are evaluating hydrogen fuel cells to provide the electricity. Kenworth offers a shorter distance battery powered electric Class 8 truck now. Volvo Group, including Mack, has been developing a fuel cell model.
Lyons: Mack at one point was developing a battery-driven drivetrain. Their idea was to run a separate high-efficient diesel turbine that would run continuously and power the battery. This application was applicable for the no-emissions zones around some of the larger ports down in California. The driver would shut off the turbine when going through the no-emissions zone and run off the battery, and then fire up the turbine when the vehicle is out of the zone to continue charging.
For your research paper, how did you develop the hypothetical scenario to model?
Lyons: We picked a haul route on the south coast of British Columbia from the forest to the sort yard. It was about the advantage of having this mass at a higher elevation and zone at a lower elevation and how that affected the size of the battery. We also looked at if haul routes didn’t have as big of elevation gain or if there were a longer highway haul.
How could you extrapolate this hypothetical situation to a useful business model for a contractor?
Sessions: Let’s start with the ideal model. For example, there’s a mining operation in Switzerland where an off-highway dump truck goes up empty and comes down the hill loaded. It never gets any external recharge; all it needs is enough energy to initially get the truck up the hill once. Coming down the hill, the truck regenerates enough energy to go back up the hill. You might say it is a perpetual motion machine.
Other situations require some amount of external energy input due to the haul route. A logging truck going up the hill without a load weighs about 25,000-30,000 pounds. When the truck comes down the hill loaded, it’s somewhere between 80,000 and 85,000 pounds. The downhill trip allows you to capture potential energy and convert it into electric energy to store in the battery. However, since not all of the haul route is in the mountains, some external energy input is needed.
For the haul route profile that we used in the paper, a driver could probably save about 35-40 percent of the amount of charge required if the driver was unable to recapture that energy coming down the hill. To recycle the energy, the downward slope gradient has to be larger than about 2 or 3 percent to overcome rolling resistance and air resistance.
What are considerations for recharging?
Sessions: If you want to recharge once a day, you are going to need a larger battery than if you want to recharge twice per day. These batteries are heavy; to last all day a battery could weigh as much as six tons, which displaces part of the log load you could be carrying, even after the weight savings from eliminating the diesel engine, transmission, and fuel tanks.
Batteries are not cheap. A battery sized to run all day could cost in excess of $60,000-$80,000. If you only need a battery half that size, it would be $30,000-$40,000. The tradeoff is the smaller the battery, the less it’s going to cost, plus the less weight is going to be subtracted from your payload, but you are going to recharge more often.
That’s where hydrogen fuel cells are a competing model. They can be fueled in about the same time as a diesel truck, they don’t have a heavy battery, and they can go a longer distance. The downside is that hydrogen is expensive, and it currently comes from natural gas.
How much does it currently cost to purchase an electric truck?
Sessions: We don’t know what the agreement is between Tesla and Mosaic. All I can say is what Elon Musk said when he was pitching the Tesla Semi that it was in the $200,000 range, including the battery. He wasn’t specific about the size of the battery, but I think it was a battery capable of providing about 600 kilowatt hours. It could be used for logging, depending on the situation, but you might need a larger battery or charge more than once per day.
Would switching to electric make forestry even more sustainable since the carbon emissions from transportation would be further reduced?
Sessions: Running on renewable power in the Northwest and being able to regenerate energy would reduce carbon emissions, but there are other factors for electric log trucks. First, they are easier to drive, because there’s no transmission so a driver doesn’t shift (although the Kenworth electric truck has a two-gear transmission). There’s the thought that they’re going to help attract a younger labor force.
Electric logging trucks have the potential of lower maintenance costs — the electric motor has one moving part. If we look at the electric motors in other sectors, the maintenance cost seems to be 30-40 percent lower than an internal combustion powertrain. And you avoid buying diesel, diesel exhaust fluid, and oil changes.
Lyons: Maybe the question for a company looking at switching to electric logging trucks is, ‘Why am I doing this?’ Is it purely because of costs? Is there a social aspect? Is it regulated?
The reason why Mack developed the high-efficient diesel turbine was because of regulations around the no-emissions port zone. I don’t know what the end motivator is going to be in forestry, but the “why” is going to play a big role in the business model.
Sessions: When people talk about some of the cost and social aspects of an electric logging truck, a diesel truck in our region is using about 15,000 gallons of diesel a year. If diesel goes to $3.50 a gallon, that’s more than $50,000 per year, and the electricity would only be, depending upon where you live, about $20,000.
The savings to the environment depends. Here in the mountainous Northwest it’s more clear because the electricity comes from hydropower, and we have regeneration possibilities, but if you get electricity burning coal or natural gas, and you are in flat terrain, it’s not as clear.
What would it take for a contractor in the Pacific Northwest to pilot the use of an electric logging truck?
Lyons: What makes somebody jump? Well, you have the example of Mosaic that’s a pretty big company. They’ve got some routes that might actually work. They’re partnering with Tesla, and socially it works with them.
Another model is purely cost driven. If the cost savings of switching to electric were a game changer, then companies would have to switch or become uncompetitive. Consider the example of switching from dozers and line shovels for building roads to hydraulic excavators.
Forestry is full of innovators and sometimes an individual will get an idea (for example an electric log truck), and they’ll just decide they’re going to try it.
Sessions: In general, it’s the larger companies, whether they’re trucking companies or firms, who buy new trucks. Another consideration is the price of electricity. The cost of electricity in Washington and Oregon is quite low, at the commercial level, compared to California. Electricity here is one third the cost in California, so if you ask is an electric vehicle going to make it in California, well there’d have to be a social or regulatory reason because the cost model will be tougher.
Which brings us to another point. Generally, the business model is that you’re going to need a high-voltage, high-amp charger to be able to charge in a short time; we’re not talking about charging a vehicle like this in your garage. Mosaic is teaming up with a provider in BC that is providing charging stations. A switch to battery electric is going to take infrastructure, whether that infrastructure is built at a sort yard or at a mill, and it may cost several hundred thousand dollars.
To develop the infrastructure, will all industry players need to be part of the discussion and solution?
Lyons: That depends on the solution that’s picked. Some of these models don’t require the same integration. They can run independently, but some do require a high degree of integration. Mosaic has sort yards and forests. Some places in Oregon won’t have that same integration. Maybe that changes the model of the electric truck in the end.
The simplest case is playing with the battery. Taking the next step, maybe it’s the hybrid truck that Mack originally produced, or it could be using hydrogen fuel cells. Integration is a good thing to point at, but we might not change the integration part of the problem so the solution might have to adapt.
Sessions: The Northwest has several advantages. We have low cost, renewable electric power and we also have this elevation potential in forestry. It’s really a very interesting story.
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