Proposed Catenary System for I-710 Zero-Emissions Corridor (Source: Siemens Mobility).
[ It makes sense to electrify trucks since fuel from oil, coal, and natural gas is finite and unsustainable, and biomass doesn’t scale up (and probably has a negative EROI or at best, is close to break-even). Sustainable electricity generation is impossible without trucks. For example, trucks are needed from start to finish in the life cycle of wind turbines — from the trucks needed to carry the 8,000 components from dozens of factories world-wide to the factory where it is assembled, to the cement and other trucks that prepare the wind turbine site and take the wind turbine to its destination, and to build and maintain the roads the wind turbine arrives on, as well as the transmission lines and towers that connect wind turbines to the grid.
Since without trucks, civilization shuts down within a week, there is no higher priority than keeping trucks running. So it is very important to see if trucks can be electrified, or if a 100% renewable electric is even possible, or there’s no point in using the remaining fossil energy to build windmills, solar PV, nuclear, and other electricity generating installations. If trucks can’t be electrified and/or a 100% renewable grid isn’t possible, the remaining fossil energy would be better spent on energy conservation, insulation, conversion of industrial farms to organic agriculture, smaller and more widely spread grain storage facilities,passive solar homes and buildings, lower speed limits, and so on.
Although trolley buses run on overhead wires in several cities, there are usually only a few hundred or less running 15 minutes apart. Scaling that up to 20,000 heavy-duty freight trucks that run just seconds apart, if that is even possible (we don’t know yet), is so energy-intensive that very few stretches of roads could be electrified.
Catenary electric trucks are proposed for zero-emissions, certainly not energy conservation or efficiency!
The ports of Los Angeles and Long Beach are trying to reduce the pollution of diesel drayage trucks hauling containers between the ports and inland warehouses. Currently the I-710 has 10,000 drayage trucks making 3 to 5 round-trips a day between the ports and inland destinations.
One solution being investigated are dual-mode catenary trucks running on 24-miles of overhead wires along the I-710 corridor. After leaving the wires to pick-up or deliver containers, catenary trucks would switch to another energy mode, either a battery, compressed natural gas, hydrogen fuel cell, or diesel. This prevents the highway from turning into a giant parking when the power goes out, allows trucks to pass one another, and catenary wires won’t be needed within the round-trip range of the other mode of power to thousands of destinations and pickup locations within the ports.
According to Calstart 2013, “This is a new situation; transit applications obviously use catenary, but those uses have headway times of 10 minutes or more. Current traffic models have truck headways of five seconds or less in the I-710 corridor, which significantly increases power demands and complicates the distribution of power to the catenary wires.”
And consider the scale. If there are 16,349 catenary trucks in 2020 (SCAG 2013), that’s orders of magnitude more than San Francisco’s MUNI catenary vehicles: 311 trolley buses and 151 light-rail cars. And heavy-duty trucks are heavy. They can weigh twice as much as a trolley bus and require more power to move.
Catenary trucks are far from commercial. There is a one mile pilot-demonstration project catenary system under construction in Carson, California. In 2015 when I wrote “When trucks stop running” this $13.5 million project was expected to start in 2015 (Calstart 2013), but since then the date has slipped to 2017 and $4.5 million more dollars. A similar project in Sweden finished in mid-2016.
In California, four demonstration trucks are planned: a battery-electric truck that can go for 10 miles after coming off the wires (ARB SEP 2014), a diesel truck, and two compressed natural gas trucks (Hsu 2016). Whether this is enough trucks to find out if it is possible to scale up to tens of thousands of trucks and what the power requirement and distribution of electricity remains to be seen.
It will be hard to build dual-mode trucks that can match the performance of today’s diesel drayage trucks, which go 400 miles between refueling, last 604,000 miles, haul up to 44,000 pounds, operate at temperatures from 23 to 113 degrees F, go up 6% grades, and travel 10 to 14 hours a day. Diesel drayage trucks are also far less expensive — a used one can cost as little as $3,000, a new one $104,360 (Calstart 2013). A Battery Electric truck (BEV) truck costs $307,890 (ICCT 2013), a hydrogen fuel cell truck $1.3 million (ARB 2015), and a natural gas catenary truck $282,000 (GNA 2012).
Why use dual-mode catenary trucks rather than plain old battery electric or fuel cell?
Battery electric trucks (BEV) may never work out. Even if 5 to 10 times as much battery energy density (Wh/kg) were achieved and other technical issues solved, they’d still weigh too much: 2 to 4 tonnes (4400 to 8800 pounds) in a 40 tonne truck. Today’s batteries are 5 to 10 times heavier than 2 to 4 tonnes (ICCT 2013). This is why the Ports of Los Angeles and Long Beach ruled out Battery-electric (BEV) trucks, which need a 7,700 pound battery that cuts too much into payload, and only goes 100 miles, half as far as required, and are out of service too long and too often, recharging for 4 hours every 120 miles (Calstart 2013b).
Siemens, which is building both the California and Sweden catenary systems points out that “With today’s technology, driving a semi-truck 500 miles would require a 23-ton (46,000 pound) lithium-ion battery, half the weight of the truck itself. [Hydrogen] Fuel cells would need a massive, $2 million hydrogen fuel tank to go the distance (Coren 2016).
And it’s not just batteries that are heavy — CNG tanks and hydrogen fuel cells (hydrogen tank alone 2166 pounds) are heavy as well, and require new fuel distribution systems and fueling stations that each cost $1 million or more. I never found a good reference for what CNG tanks and systems would weigh, the best I could find was this: “It is not practical to get 300 gallons of diesel equivalent in CNG on-board a truck — the combined weight of the gas and the system is over 10,000. If you work the weight of the fuel, 300 gallons of diesel = 1,140 gallons of CNG, which weighs 1.81 pounds per gallon, for a total of 2,072 pounds. Add another 1,800 pounds for the CNG tanks, and about 1,300 pounds for the racks and protective plates, and the fully loaded CNG system weighs in at over 5,172 pounds, 141 percent heavier than the full 300-gallon diesel tanks” (Schneider 2014).
Another disadvantage of BEV trucks is the need for twice as many (32,968) as dual-mode catenary/battery (C/B) trucks (16,349) because the battery on the C/B truck can be continually charged from the overhead wires. Nor would battery swapping solve the BEV problem, since it would be too expensive to carry multiple batteries for each truck (SCAG 2013) and build expensive battery-swapping stations (Berman 2011).
Another zero-emission solution rejected by the ports was a fixed guideway system, because over 20 years it would cost 14 times more than a dual-mode catenary system (GNA 2012 page 18).
Fixed guideway system. Source: Klinski, J. 2015. LEVX intermodal freight transport system. Port of Hueneme. California sustainable freight action plan. Magna Force, Inc.
Question: How much power would catenary trucks on 24 miles of wires along I-710 need?
Answer: from .29% (ICF 2014) to 1% (my calculation) of all the electricity generated in California for a year. That means just 2,400 to 8,275 of California’s 175,000 miles of roads would use all of California’s electricity.
My assumptions for I-710 catenary:
- 16,349 hybrid catenary trucks I-710 in 2020 (SCAG 2013)
- 3 round-trips per day per truck (Calstart 2013. On good days 4 to 5 trips are made)
- 48 miles per round trip (24 * 2 miles of catenary wires on I-710)
- 313 days of drayage deliveries (ports are closed on Sundays)
- 3.5 kWh/mile (2.21 kWh/kilometer) due to the inefficiency of the dynamic loading on catenary wires, with a 10% efficiency loss assumed (ICCT 2013).
- California produces 250,561 GWh of power a year (ICF 2014)
Calculations:
- 2579 GWh needed by all catenary trucks per year = 16,349 trucks * 3 round-trips * 48 miles per trip round-trip * 313 days per year * 3.5 kWh/mile (3,438,783,264 kWh)
- 1% of all generated California electricity used per year = 2579 GWh / 250,561 GWh per year California
- 100% / 1% * 24 miles = 2,400 miles of roads would use all of California’s electricity
- .16 GWh per truck per year = 2579 GWh per year / 16,249 trucks
But ICF 2014 estimates .29% of annual power. That’s still a lot!
ICF 2014 “Aggressive Adoption” by 2030 (all trucks electrified) assumptions for I-710
- .29% of all generated California electrity used per year = 722 GWh all trucks/year (table 13) / 250,561 GWh per year California
- Consume 3 kWh/mile (page 87). Using 3 kWh lowers my calculation to 2211 GWh/year, .88% of California electricity, still 3 times more than .29%
- 36,100 trucks = 722/.02 .02 GWh/year/truck (table 33), all trucks 722 GWh/year.
- 241,000,000 total miles all trucks a year (Table 12). Therefore, every day all trucks drive 769,968 miles collectively (241,000,000 / 313 working days).
- 100% / .29% * 24 miles = 8,275 miles of roads would use all of California’s electricity
- Just 21 miles/day on catenary = 769,968 miles a day all trucks / 36,100 trucks. In my calculation each truck goes 144 miles a day, and then 56+ miles using the other mode, since the specs call for 200 miles a day. If just 21 miles, the other mode must go 180 miles a day. That can’t be right!
Conclusion
Even if the ICF 2014 estimate of .29% of all California electricity is correct, that’s an awful lot of electricity. Just 8,275 miles of California’s 175,000 miles of roads would use all of California’s electricity– think how much power America’s 10 million trucks would need over 4 million miles of roads.
Since fossil fuels are finite and global production has peaked, or will soon (i.e., oil, coal, natural gas), it makes sense to try to run transportation on 100% renewable electricity. But is an 80 to 100% renewable electricity system even possible? I make a case in “When trucks stop running” that it isn’t.
And catenary doesn’t solve the main problem, which is keeping tractors and harvesters running so they can plant and harvest food. How would you string overhead wires across millions of acres of cropland?
Catenary also locks in a very expensive infrastructure on a road that may not be heavily used in the future. Will the ports continue to move as many goods if the unreformed financial system crashes again and trade drops in the consequent depression, or when energy becomes too expensive or too scarce a component of the supply chain? It’s more likely globalization will decline and more goods made locally in the future.
I was very upset that the father in “Angela’s ashes” spent money on booze rather than food for his children. So is a goal of zero-emissions rather than energy efficiency the best way to spend our remaining energy when no commercially viable way of replacing oil is even in sight, and it takes 50 years to make an energy transition (Smil 2010)?
References
ARB. September 2, 2014. Heavy-duty hybrid vehicles technology assessment. California environmental protection agency, Air Resources Board.
ARB. 2015. Technology assessment: Medium- and Heavy-duty fuel cell electric vehicles.
Berman, B. 2011. Plug-and-play batteries: Trying out a quick-swap station for E.V.’s. New York Times.
Calstart. 2013. I-710 project zero-emission truck commercialization study. Calstart for Los Angeles County Metropolitan Transportation Authority. 4.7.
Coren, M.J. June 23, 2016. Siemens says it can power unlimited-range electric trucks using a 150-year-old technology. QZ.
Edelstein. July 10, 2016. Road for electric trucks with trolley-like catenary opens in Sweden. greencarcongress.
GNA. March 8, 2012. Zero-emission catenary hybrid truck market study. Gladsteni, Neandross & Associates.
Hirsch, R. L., et al. 2005. Peaking of world oil production: impacts, mitigation, & risk management. Department of energy.
Hoffert, et al 2002 Advanced Technology Paths to Global Climate Stability: Energy for a Greenhouse Planet, Science. Vol 298.
Hsu, T. July 18, 2016. 100-Year-Old Street trolley technology could completely change trucking. trucks.com. CNG: Kenworth Trucks , BAE Systems and TransPower.
ICCT. July 2013. Zero emissions trucks. An overview of state-of-the-art technologies and their potential. International Council for Clean Transportation.
ICF. September 2014. California transportation electrification assessment. Phase 1: final report. ICF International.
SCAG. February 2013. On the Move. Southern California delivers the goods. Final report. Southern California Association of Governments.
Schneider, D. February 10, 2014. The fuel alternatives: CNG & LNG part 1. wearethepractitioners.com
Smil, Vaclav. 2010. Energy Transitions: History, Requirements, Prospects. Praeger.
