Transit Leading the Way toward Heavy-Duty Electrification

November 20, 2017

Heavy-duty transportation is proving to be fertile ground for fleets’ efforts toward electrification, most notably among transit agencies – many of which have already begun shifting their complement of buses to all-electric and hybrid-electric options.

Indeed, heavy-duty EV technology is catching up with fleets’ emphasis on fuel- and maintenance-cost savings, as well as compliance with mandates for cleaner air. No longer exclusively the realm of light-duty vehicles, transit fleets are the epicenter of activity illustrating how electrification is viable for all spots on the transportation spectrum.

Genevieve Cullen, president of the Electric Drive Transportation Association (EDTA), notes that in terms of EV technology and deployment, the medium- and heavy-duty sectors are “a couple steps behind light-duty,” but the gap is closing.

Historically, the main challenges were the cost of vehicle acquisition (tied largely to the cost of batteries), the vehicles’ range, and unknowns related to how EVs would perform in diverse bus duty cycles.

To some extent, those hindrances have been surmounted: A number of early adopters have proven that electric buses perform just as well – if not better – than their diesel counterparts. Moreover, battery costs have decreased in recent years – making the purchase price of electric buses more palatable – and advancements in storage capacity and charging technology have helped fleets meet the needs of their revenue routes. Market competition is also having an effect on vehicle availability and cost.

“All manufacturers are taking a fresh look,” Cullen says, with various OEMs rolling out new and expanded bus platforms in both battery-electric and hybrid-electric configurations.

In turn, more transit fleets are deploying EVs, and the rate of return is improving substantially.

A handful of transit organizations have been on the bleeding edge of electrification for years and paved the way toward strong rates of return and decreasing total costs of ownership. Among them is the San Francisco Municipal Transportation Agency (SFMTA), which has been moving people around the Bay Area via electric-powered transportation “for decades,” says SFMTA’s Paul Rose.

“Electric trolley buses carry our heaviest loads on some of our most demanding routes,” he remarks. These trolleys are powered by overhead lines – a technology that has been in use for more than 100 years.

Fast-forward to the 21st century, and SFMTA remains committed to electrification. By 2019, the agency will have replaced its entire rubber-tire fleet with 278 electric trolleys and 536 hybrid-electric vehicles. Those hybrid-electric buses – manufactured by New Flyer – combine an electric drivetrain with a diesel engine that runs on B20 biodiesel blend.

By 2035, the agency’s entire fleet – cable cars, buses, street cars, light rail vehicles and trolleys – will be all electric.

To edge toward these goals, SFMTA will soon be issuing a request for proposals “to test dozens of electric buses on some of our smaller community routes,” Rose says.

“The technology is just getting started,” he notes. “When electric technology is ready, we can upgrade buses within our new electric hybrid bus fleet to run completely on battery power.”

Just south of SFMTA territory, the Santa Clara Valley Transportation Authority (VTA) is following a similar path. The agency already has 246 hybrid buses in its fleet, and that number is expected to rise to 302 by the end of this year. Twenty-nine are New Flyer articulated hybrids using BAE’s hybrid-drive system and Cummins ISL engines; 135 are Gillig 40-foot hybrids with BAE drives and Cummins ISB engines; and 138 are Gillig 40- and 30-foot hybrids with Cummins ISB engines and Allison hybrid-drive systems.

This December, VTA is taking delivery of a demonstration Proterra all-electric bus. A total of 10 units will be delivered and placed into regular service in 2018.

VTA’s Linh Hoang explains that these battery-electric buses could be the tip of the iceberg, but cautious optimism is the sentiment.

“The long-term target for our electrified fleet will be heavily dependent on actual electric bus performance,” she says. “The range in actual service is a concern. For operational flexibility, they will need to be dependable to over 200 miles.”

VTA will take these buses through their paces next year. If they perform according to projections, the agency will receive 25 additional Proterra buses in stages through 2021.

“If all is trending as anticipated, with improved range and dependability, an additional 70 electric buses will be included in our next major procurement, come 2024,” Hoang says.

“If batteries continue to improve at the rate they have for the last five years, then 250-mile-range electric buses will be available by 2025 and, at that point, diesel and hybrid buses will become the ‘specialty service,’ used only for the longest routes. It is anticipated that all new buses will be electric after 2028,” she notes.

Across the country, the Southeastern Pennsylvania Transportation Authority (SEPTA) is also in the midst of a shift to electrified transit that has been many years in the making. Erik Johanson, SEPTA’s director of business innovation, says 800 of its 1,400 buses are currently hybrid-electric. That number is projected to increase to 1,300 of 1,400 by 2021.

Notably, the agency has not purchased a traditional diesel bus since 2005.

In addition to the huge proportion of hybrids, SEPTA is also beginning the deployment of New Flyer trackless trolleys, as well as all-electric buses: The first of 25 Proterra battery-electric units will come online soon. Each bus costs about $800,000 (compared to $700,000 for the hybrid-electrics) and is expected to require full battery replacement once during its projected 18-year lifespan, at an additional cost of approximately $75,000.

SEPTA’s forecasts indicate that the capital costs (vehicle acquisition plus infrastructure costs, including incentives) of battery-electric buses will exceed those of hybrid-electric buses: $2.87 per mile versus $1.73 per mile. However, battery-electric buses edge out hybrids in operations and maintenance costs (infrastructure and vehicle maintenance costs plus the cost of fuel/power): $1.81 per mile versus $2.94 per mile.

So, in terms of total lifecycle costs, it’s a dead heat between all-electric and hybrid-electric: $4.68 per mile versus $4.67 per mile.

For SEPTA, it will be a matter of weighing the pros and cons. The main advantages of all-electric buses are their substantially lower operating and maintenance costs, along with zero tailpipe emissions and a practically silent ride.

One of the disadvantages of all-electric – an as-yet unproven vehicle range over a bus’s useful life – will be partly tested during the pilot stage of SEPTA’s battery-electric rollout. The other primary disadvantage – the costs associated with recharging infrastructure, such as the need to build a new substation – is largely unavoidable.

Other early adopters of battery-electric buses are also cautiously optimistic. Richard Tree, transit manager for the City of Porterville, Calif., says his agency’s board of directors made a commitment in 2015 to begin shifting to emissions-free transportation – but doing so wracked the nerves a bit.

“We had a lot of fears of being an early adopter,” he says, noting that being a small agency with a small fleet (18 buses on nine fixed routes) wouldn’t leave much room for error.

With funding in place – mainly $9.5 million from the California Air Resources Board, along with some federal and local dollars – the City of Porterville ultimately pursued a contract with GreenPower Motor Co. Inc. to buy 10 of its 40-foot EV350 all-electric buses. (GreenPower is also providing one additional bus in-kind.) Two of the buses are currently being built at GreenPower’s factory in China and are scheduled to be delivered in December. Thereafter, sets of three buses will be delivered every 45 to 60 days.

Tree says the EV350s that are coming online feature re-engineered battery systems (460 kWh) that will give the agency the 250-mile range it needs right out of the gate. The city runs routes over relatively long distances and time frames (6 a.m. to 11 p.m.), necessitating the high operating range.

North of the border, the City of St. Albert, Alberta, is also at the early stages of pilot testing of BYD all-electric buses. Three have been in revenue service since the summer, and four more are on order and scheduled for delivery in December or early 2018. This deployment is quite a swing for the city – from 60 all-diesel buses to 100% electric.

Kevin Bamber, director of St. Albert Transit (StAT), notes that the agency first trialed BYD’s all-electric bus in 2014 and continued to test newer generations of the product into 2015. In real-world conditions, the bus consistently achieved about 1 kWh of energy consumption per kilometer, which was in line with the range StAT required between charges.

The agency’s first three battery-electric units have cumulatively run about 50,000 km over the last four months. These buses have shown even better performance: about 0.8 kWh per kilometer. Bamber says the longest run that one of these vehicles completed was 290 km (180 miles), and that bus returned to the yard with about 18% charge remaining: performance that exceeded StAT’s expectations.

Moreover, the fuel-cost savings have been substantial. StAT’s diesel buses cost $0.45 to $0.50 per km; the new battery-electric units are averaging about $0.09 per km.

Between this kind of fuel-cost savings and the buses’ additional benefits – reduced maintenance costs prime among them – StAT is hoping the case can be made to city planners to continue plowing forward with the transition to all-electric transit.