LANCASTER, CALIF.—One single diesel transit bus consumes the equivalent of 10,440 gallons of gasoline a year, according to the Federal Highway Administration. Replacing that diesel-burning transit bus with an electric bus has some obvious benefits. Electric buses improve local air quality, because the particulates that come from burning diesel don't exist. And, according to the Union of Concerned Scientists, an electric bus runs cleaner than a diesel bus no matter where you plug it in on the US grid, even if you're plugging into a grid fed by fossil fuels.

In the desert north of Los Angeles, a Chinese company called BYD (short for "Build Your Dreams") is banking on transit managers realizing this. BYD offered Ars a tour of its Lancaster facility in July, and we found a bustling factory floor filled with 900 workers who were building, welding, shaping, and painting about 90 buses in various stages of completion. The company's workforce, recently unionized, is expected to grow to 1,200 in the near future.

So far, BYD has put more than 250 electric buses on US roads, and, as of mid-July, the company had more than 400 orders in the pipeline. That's a significant number of buses in this nascent industry: last December, Reuters estimated that only 300 public buses on US roads were electric. Of course, BYD's numbers include publicly and privately owned electric buses, while Reuters' statistic only tallies public buses. Still, the numbers show just how aggressively the electric bus industry is growing, considering the size of the market just six months ago.

BYD isn't the only company making electric buses for North America: companies like Proterra and New Flyer Industries have also been churning out their fair share of battery-operated vehicles. As cities, counties, companies, and colleges try to move away from diesel, factories like BYD's stand to grow quickly.

Let’s build a bus

Megan Geuss

Megan Geuss

Megan Geuss

On the face of it, buses seem like prime candidates for battery technology. Buses generally move slowly, with no real need to go faster than 65mph. They have set routes, so "range anxiety" isn't an issue. They frequent dense urban areas where the quiet squeal of a battery is preferable to the rumble of an engine.

The downsides of swapping a diesel bus fleet for a battery-electric one is that bus routes may need to be reorganized to allow for one bus to take over while another one charges.

Electric buses aren't cheap up front, either (they can run between $100,000 to $300,000 more than their diesel competitors), but they also require less maintenance.

BYD has made some interesting choices to meet the early demand for electric buses, down to the battery chemistry. The company uses lithium iron phosphate batteries instead of the automotive industry's preferred lithium cobalt-based batteries. Iron-phosphate batteries are less volatile, so for a while, BYD didn't build them with a cooling system (although that's now not the case). Iron-phosphate batteries are lower voltage than comparable cobalt-based batteries, but there's also less of a concern about disposal. As BYD Senior Project Manager David Trimble told Ars, "you can crush 'em, burn 'em, stab 'em, sit 'em in the heat, and nothing happens. We’ve tested this out ourselves: throw 'em in a fire; they’re not volatile."

For a municipality looking for the safest way to transport thousands of citizens a day, that's a big benefit.

Putting together the bones of the bus

In our tour of the BYD factory, Trimble walked us through exactly how a bus gets made. BYD's smallest bus is 30 feet long, and its largest is an articulated 60-foot bus (that is, it has an accordion-like section in the middle so the bus can take corners more easily).

Megan Geuss

Megan Geuss

Megan Geuss

Megan Geuss

Megan Geuss

Megan Geuss

Megan Geuss

Megan Geuss

Megan Geuss

Megan Geuss

Megan Geuss

Megan Geuss

Paint and interior

Every city has its own bus design, so BYD's work is necessarily very customized. Trimble calls it the "West Coast Customs" of buses. When a bus order is placed, typically the orderer will work with an in-house designer to get the look right. Sales people and designers work in offices above the factory floor.

Another thing that ends up getting tailored to the customer is range. BYD's buses and trucks usually have 150 to 250 miles of range, although longer ranges are possible, Trimble told Ars. "Some customers want all these crazy electronics, and that does shorten the range," he said.

"The good thing about electric buses, or electric vehicles in general, is the technology is always growing," Trimble added. "So let's say we have a bus now that does 250 miles, pretty much a year from now that’s gonna be obsolete." Transit agencies that really need long distances might not be able to place orders now, but in a year, they will be, Trimble was certain.

The bus batteries, it should be noted, are made down the road in Lancaster at a separate factory owned by BYD Energy.

Megan Geuss

Megan Geuss

Megan Geuss

Megan Geuss

After the bus is painted, it moves to the chassis line. On an electric bus, there's less machinery than you would find on a diesel. No transmission, no driveshaft. That's part of what makes electric motors easily maintained. Instead, the chassis line is where the motor control unit, the cooling systems for the control unit, and the low-voltage battery to power the bus' auxiliary systems get put in.

The most important component on an electric bus is arguably the battery, which BYD covers with a 12-year warranty. Those 12 years are "basically the life of the bus," Trimble said, and in the interim, if a transit agency's maintenance crew finds an issue with the bus related to the battery, BYD comes out and swaps the battery for free.

The horsepower on a BYD bus is also a customizable thing, and Trimble said one of their models has 215hp, which is not unusual for a bus.

As we mentioned above, BYD just started adding cooling systems to their batteries. The purpose isn't to prevent fire, but to keep the battery at an optimal temperature while it works.

Final assembly

Final assembly is the line that makes the bus look like a bus. This stage is usually very unique to the bus that's being ordered, so it can take the longest to finish.

Megan Geuss

Megan Geuss

Megan Geuss

Test test

Before the buses are sent off to their buyers, they're charged, tested, and sent through quality control.

On the floor at the time of our tour were a number of buses bound for Stanford University, Martha's Vineyard in Massachusetts, and BYD's hometown, Lancaster.

Buses in Lancaster are managed by the Antelope Valley Transit Authority (AVTA), and while that may be a completely unknown bus system to someone who lives outside of Southern California, AVTA is on the verge of historical mention. According to BYD's Public Relations contact, Pam Clark, AVTA will likely become the first major metropolitan transit agency to transition its bus system to be completely electric.

AVTA ordered 79 buses from BYD and will likely put the final one into operation at the end of this year or in the beginning of 2019. The only competition that AVTA has at this point comes from cities in China. "I think of it like Sputnik, the race against China to go all-electric, and AVTA has been leading that charge now for a while," Clark told Ars.

Megan Geuss



Megan Geuss

Megan Geuss

Megan Geuss

Megan Geuss

Megan Geuss

Megan Geuss

After the buses are tested, they are sent to their new homes. If the customer is close by, often BYD will simply hire a driver to deliver the bus to its new home.

But what if BYD is delivering across the country? Currently, our national charging infrastructure is barely on the cusp of being able to support long-distance drives for bus deliveries. Smaller buses can be trucked out, if necessary. Additionally, "If there’s any 60-footer that’s gotta go a long way, we’re gonna have a truck and a generator that’s got a hook up," Trimble explained. "And so we’ll drive and follow and charge it and once it gets low we’ll pull off somewhere and charge it again."

It's a complicated circus to deliver a bus, but after the detailed work of building the thing, delivery may be the easiest task.