Fuel CellElectric Vehicles,part 2

EV-310b

This course is presented as part of Evannex Universitya free, open learning environment that presents concise, video-based mini-courses for those who have interest in electric vehicles (EVs)

Comparing the TechAny comparison of two important technologies can be debated endlesslyWell compare BEVs and FCEVs in four broad categories:technologyvehicle characteristicsrefueling requirementsenvironmental impact

BEVvs.FCEV

>> Any comparison of two important technologies can be debated endlessly with opponents of one approach arguing against the other and vis versa. Having said that, well give you our take in part two of this EVU mini-course.

>> Well compare BEVs and FCEVs in four broad categories:>> technology>> vehicle characteristics>> refueling requirements>> environmental impact

The graphics presented were prepared by EVannex as an infographic in 2014. Ill update the numbers where appropriate.

FCEV vs. BEV

BEVFCEV

Our comparison of fuel cell technology and battery electric vehicles begins with consideration of technology. Information about BEVs is shown in red on each of the figures that follow, while information about fuel cell vehicles is shown in gray. Well consider five technology subcategories, beginning with the power source for each vehicle.

For the BV, the power source is the grid Its ubiquitous, efficient, and highly reliable. For the fuel cell vehicle, power is derived from hydrogena commodity that is created as part of an industrial process, shipped to a fueling station, and then stored on-board an FCEV.

For BEVs, power storage is achieved with a lithium-ion battery. A fuel cell and a battery serve as power storage for a FCEV.

Power conversion takes the path shown in the central column. For BEVs, power flows from the grid to the battery and on to the electric motor. For FCEVs it flows from the hydrogen fueling station, into on-board tanks and then to the fuel cellFrom there, it flows into a battery or directly to an electric motor.

The energy capacity of a fuel cell is significantly higher than the best BEV batteries available on the market today. For example, for the Toyota Miraian FCEV available from Toyota in very limited quantitiesenergy capacity is 114 kWh, almost 40 percent greater than the Tesla Model S 85 kWh battery.

Finally, the overall energy efficiency is dependent on grid quality for BEVs and Hydrogen extraction technology for FCEVs.

FCEV vs. BEV

BEVFCEVToyotaMiraiTeslaModel S

As a representative comparison of BEV and FCEV vehicles, well use the Tesla Model S (jndicated in red) and the Toyota Mirai (indicated in grey). This is slightly unfair because the Model S represents the top-end of the BEV marketplace, but its also an indication of what many BEVs could become in the future.

In the performance category, the Model S is the clear winner, with performance specs that would be the envy of any car.Its acceleration and hp far outstrip the Toyota Marai.

The Model S BEV also comes out on top for fuel efficiency, but has a range that is about 10 percent lower than the Marai FCEV.

Both vehicles are heavy with the extra weight of the Model S likely attributable to the large battery. The unique battery design of the Model S provides interior volume that far outstrips the Marai, and both cars are relatively large.

The Marai is significantly less expensive, but is not inexpensive, costing $57,500.

Finally, and significantly, Toyota projects that only 3000 of its FCEVs will be on the road by 2017 while Tesla Motors will have at least 160,000 BEVs sold by that time.

FCEV vs. BEV

BEVFCEV

BEVs have a distinct fuel cost advantage over FCEVs, although costs for hydrogen are indicative of the rarity of the fuel today and will undoubtedly come down as the number of fueling stations grows and production techniques improve.

As gasoline prices decreased throughout 2014, the fuel cost saving provided by BEVs, although still significant, have been reduced somewhat.The 15% number shown in the first column is had grown closer to 20 - 25 percent

One of the curiosities of the push for FCEVs is the continuation of a vehicle fueling paradigm that is not home-based. The ability to refuel a BEV at home offers distinct cost and time savings. In addition, unlike gas stations, it highly unlikely that hydrogen refueling stations will be located on every other corner, meaning that they will be placed strategically on well-traveled routes just like BEV charging stations today.

Today, BEV chargers outnumber hydrogen fuel stations by a wide margin, in fact, three orders of magnitude. Also a quick update, the number of Tesla superchargers now in operation in the United States is well over 200 and growing.

FCEV refueling occurs quickly, offering a distinct time advantage over BEVs. However, that is only true with the current BEV recharging paradigm. Tesla Motors has begun a pilot program of battery swaps that will enable a BEV to obtain a fully charged battery in about 5 minutes. If it succeeds and is adopted more widely, the FCEV refueling time advantage will be negated.

FCEV vs. BEV

BEVFCEV

Both FCEVs and BEV produce zero emissions and can therefore be considered environmentally friendly. However, there is discussion about the so-called well-to-wheel environmental costs for each technology.

The well-to-wheel cost for FCEVs depends on the degree to which the hydrogen extraction and delivery process uses energy and produces pollutants. Liquid hydrogen must be transported from the production facility to the hydrogen fueling stationexpending energy along the way.It must then be maintained at minus 250 deg C, requiring energy input to maintain that temperature.

The well-to-wheel cost for BEVs is a function of the energy source producing electricity. For example, hydro power has very low environmental cost while coal has high cost. The efficiency of the grid also comes into play.

On balance it can be argued that the well-to-wheel environmental cost for BEV is considerably lower that the cost for FCEVs. A quantitative indication for green house gases is shown in the far right hand column of the graphic.

a free study guide for all EVU mini-courses is available for download from our website For a complete list of mini-courses and the study guide, visit: www.evannex.com

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