The All Day Electric Bus
By Bill Moore
By Bill Moore
Beit Shemesh, Israel - August 2, 2000 -- It's a long way from Israel to Glitter Gulch, otherwise known as Las Vegas, Nevada, the fastest growing little town in America. But for Electric Fuel Corporation, with headquarters in New York and its R&D facilities half a world away it could be either a blind canyon or gateway to the promise land. Before the end of the year, a lone transit bus will make its debut on the jaded streets of the gambling and convention capital of the World.
Lord knows the city needs it... and several hundred more! The population of the once dusty little whistle stop on the Union Pacific railroad line, passed one million some time ago and is growing... no make that sprawling at the fastest rate of any place in America. As we've reported previously in EVWorld, the city fathers and even some of the casinos are experimenting with electric transportation from Bombardier NEVs at McCarran Airport to three electric monorail trains linking several casinos.
What's needed is an efficient mass transit system, at least for the millions of tourists and conventioneers who fly into town every year, if not for the locals. And quiet, pollution-free buses like the one pictured here is just the ticket. That is if it can pass muster in the brutal world of daily transit operations. Enter Electric Fuel Corporation's 40-foot, all electric, zinc-air-powered transit bus. Here is a full-sized city bus that emits no pollution! Zero! Zip! Nada! Zilch! It will not only carry a full complement of passengers in its air-conditioned cabin, but it will do it, according to Yoel gilon, director of EV Technology at Electric Fuel Corporation, "all day" something no other battery electric buses can currently claim.
Pioneering Zinc Air Technology
Founded in Israel, Electric Fuel Corporation is now a publicly trades Nasdaq stock (EFCX) that is now a decade old with some 200 employees, most located in Israel where the firm has its research and zinc air battery manufacturing facilities.
While many have experimented with zinc air batteries over the years, few have progressed to the state of commercial development achieved by Electric Fuel, which ran a demonstration programs with the German Postal Service. But even with successful demonstrations like that in Germany and the run of a 4 ton lorry (commercial) truck between London and Paris the Fall of 1997, the company has had a hard time convincing the powers that be that zinc air technology is a viable power solution for motor vehicles. The problem isn't that the system can't provide the energy needed to propel EVs large or small.
It can... in spades. As Gilon explained, zinc air batteries offer extraordinary energy density levels that are 4-6 times that of lead acid and twice that of lithium ion.
Zinc air batteries operate, in some respects like a fuel cell and in others like a common storage battery. Its zinc electrodes are submersed in an electrolyte. Oxygen in the atmosphere reacts with the zinc and generates electricity and zinc oxide. Once the battery has been discharged, the spent zinc electrodes can be recycled.
While zinc air clearly has an energy storage advantage over other battery technologies, its Achilles heel is that it cannot be recharged, at least in the conventional sense. It is, in effect, what is called a primary battery similar to the type you¹d use in, say a flashlight. Once it has discharged its energy, it has to be replaced with a fresh battery. However, unlike your common D-cell battery, the zinc air battery can be recycled and this is the technology that Electric Fuel Corporation has perfected. The company has developed an automated system to recycle and replenish its large zinc air batteries.
In a theoretical consumer setting, Gilon estimated that a passenger car could have its zinc air batteries swapped out in 10 minutes time, assuming the car manufacturer made them readily accessible. In practical terms, however, few consumers would probably relish weekly trips to the recycling center or service station.
Gilon explained to EVWorld that Electric Fuel Corporation also perfected a way to get the power out of the battery so it could be used in vehicle applications. This is important because cars and trucks will make erratic power demands on a battery when it needs extra energy to accelerate or climb a hill. EFCX's zinc air batteries demonstrated during its German Postal Service program that it could handle the demands of vehicles weighing 4 tons giving them an average range of 200 plus miles. Gilon stated that the postal drivers who used the zinc-air powered trucks found that they had as much or more power than the conventional trucks they were used to.
In day-to-day operation, the German trucks needed to have their zinc air batteries replaced once or twice a week at most. EFCX had set up a recycling facility in German to replenish the batteries, unfortunately with the conclusion of the test, the program was cancelled and the plant taken apart.
While the German Postal demonstration is no longer in operation, Gilon did point out that Italy's largest electric utility has licensed Electric Fuel's technology and is proposing a fleet of 50-100 taxi cabs powered by zinc air batteries in Milan, Italy.
The American Bus Project
We turned our attention to Electric Fuel's current project in America, a 40-foot transit bus powered solely by zinc air batteries. This project is co-funded by the US federal transit administration and BIRD or Bi-national Research and Develop, a cooperative venture between the US government and Israel to promote technology sharing between the two nations. According to Gilon, the project has been two years in development and is about ready to move from Phase One, which was the system integration phase. In Phase Two the bus undergoes testing of its GE-designed energy management system and finally field testing in Clark County, Nevada, whose Regional Transit Authority is also a participant in the project.
Gilon explained that the Las Vegas was chosen as the field test site because of the strong interest and support shown by the US. Senator Harry Reid (D), the Governor and the Secretary of Transportation.
According to Gilon, the bus meets what he calls the Federal Transit Administration's "white book" for transit bus performance including acceleration and climbing. The one shortcoming a zinc air-only battery system is that it cannot take advantage of a regenerative braking system, which is important in recapturing some of the energy lost braking the vehicle, something buses do a great deal.
As a result the bus has a second battery system designed specifically for the regen system. Power from this 20kW NiCad battery system is used for additional acceleration power and to help run the auxiliary systems on the bus. There are plans to eventually replace this battery system in Phase Two with ultra capacitors. Gilon said that this will help reduce the cost of their batteries.
Electric Fuel and its partners have a short list of improvements for the bus, one of the first being the reinstallation of two seats in bus which had to be removed to accommodate the NiCad battery system. "Other than that, this bus is ready for full transit city operation ..." Gilon said.
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