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New UMTRI paper reviews major advantages and disadvantages of battery-electric and fuel-cell vehicles
1 February 2016
A new report from the University of Michigan Transportation Research Institute (UMTRI) reviews the major advantages and disadvantages associated with battery-electric vehicles (BEVs) and fuel-cell vehicles (FCVs). The team of Brandon Schoettle and Dr. Michael Sivak also incudes information for current gasoline-powered internal combustion engines as a baseline comparison.
In addition to reviewing the technical literature, the UMTRI researchers interviewed experts in the automotive and energy sectors regarding their views concerning these issues. Among their findings:
|A note on fuel pricing and cost per mile|
|In their report, Schoettle and Sivak used a national average fuel price for electricity of $0.12/kWh (EPA is now using $0.13 as the average price), resulting in an average effective cost per mile for BEVs of $0.04|
|However, there is a great deal of variability in charging pricing, based on location, time of day, season, and type of charge (i.e., residential, commercial, office). For example, in the San Diego, California territory of SDG&E, optimal time of use residential EV charging rates range from $0.19/kWh to $0.46/kWh depending upon the season and time of day.|
|For commercial, standalone chargers, the rates can be higher. For example, in North County San Diego, a non-member charging at a Blink Level 2 station will pay $0.59/kWh—almost 5 times the average $0.12/kWh cited in the report. On the other hand, a Tesla driver charging at a SuperCharger station pays nothing.|
|For FCVs, Schoettle and Sivak note, the effective cost per mile is currently $0.09. For current gasoline-powered ICE vehicles at an average fuel economy of 23.3 mp and a fuel price of $2.35 per gallon, results in a cost of $0.10 per mile.|
BEVs currently offer the most readily available alternative fuel source via the existing electric grid. Additionally, more BEV models are available to the public (relative to fuel-cell vehicles) and they offer the best fuel economy, resulting in the lowest cost to operate (per mile). BEVs also tend to produce the lowest amount of greenhouse gases (well-to-wheels) per mile.
However, the driving ranges of these vehicles are currently the lowest of any vehicle type, while also requiring the longest time to refuel or recharge.
FCVs have significantly longer driving ranges and lower refueling times than comparable BEVs, and it is also possible for them to use the least amount of petroleum (well-to-wheels) per mile, depending on the type of hydrogen used.
On the other hand, only a small number of vehicle models are available, and only in the most recent model years. Similarly, the hydrogen-refueling infrastructure is practically nonexistent outside of California.
There is a general consensus among the experts that expansion of the hydrogen infrastructure needs to precede the mass introduction of FCVs in order to raise consumer confidence in the availability of hydrogen fuel.
Both alternative fuels and vehicle types require additional training for emergency responders and mechanics, but also generally require lower overall maintenance than a traditional gasoline-powered vehicle.
Based on the average mix of renewable and non-renewable electric power sources in the US, the average well-to-wheels GHG emissions for BEVs is the lowest, at 214 g/mi. Depending on whether gaseous or liquid hydrogen is used, the corresponding values for FCVs range from 260 to 364 g/mi, respectively. Gasoline-powered vehicles produce the most GHGs per mile, ranging from 356 to 409 g/mi, depending on the specific type of ICE (direct versus traditional fuel injection, respectively).
As a comparison baseline for the refueling infrastructure, the UMTRI team noted that there are approximately 114,000 individual gasoline stations covering all 50 states and the District of Columbia. The cost of installing a gasoline station is typically in the range of $1 million to $2 million.
Expansion of the BEV charging network is relatively inexpensive—approximately $1000 for home-based charger installation, and ranging from approximately $10,000 to $100,000 for public stations. Hydrogen refueling stations currently have a relatively high cost for construction and installation, costing approximately $3 million to $5 million for a public station.
|Relevant aspects of vehicle performance for battery-electric vehicles (BEV) and hydrogen fuel-cell vehicles (FCV). (Where appropriate, green = best, yellow = middle, and red = worst.) Source: Schoettle and Sivak. Click to enlarge.|
Brandon Schoettle and Michael Sivak (2016) “The Relative Merits of Battery-Electric Vehicles and Fuel-Cell Vehicles” UMTRI-2016-5