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California’s new ZEV rule introduces the BEVx; ARB staff expects these vehicles to play a longer-term role than plug-in hybrids

On Friday 27 January, the California Air Resources Board (ARB) adopted the new Advanced Clean Cars (ACC) package that sets out the regulatory emissions and technology requirements for light-duty automobiles through model year 2025. (Earlier post.) The Zero Emission Vehicle (ZEV) regulation—one of the three main regulatory packages that constitute ACC—introduces a new regulatory vehicle category: the BEVx, or a battery-electric vehicle with a small “limp-home” range extending engine or APU (auxiliary power unit)—i.e., not a series-hybrid type vehicle such as the Chevrolet Volt equipped with a full-capability engine.

Under the ACC, ARB will award BEVx credits on the same basis as BEVs—i.e., on zero-emission miles (the simplified ZEV credit scheme under the ACC is a linear one based on those zero-emission miles). BEVx vehicles can provide up to 50% of the pure ZEV requirement for manufacturers, and so they may emerge as a significant vehicle type.

In the Initial Statement of Reasons (ISOR) published prior to the Board meeting, ARB staff noted that “some manufacturers” proposed this new class of advanced vehicles for separate treatment as part of the ZEV program. (During the public hearing on the ACC rule package, comments from ARB staff and the Board indicated that BMW was particularly interested in this classification.)

The basic rationale, according to ARB staff, is that such a vehicle has the potential to expand the BEV market beyond current market estimates by giving interested customers an extra measure of confidence about range, and if successful, would add substantial zero-emission vehicle miles traveled (VMT) to the overall California fleet.

It was suggested during the hearing that such a vehicle might even deliver more all-electric miles than a battery-only electric vehicle, as the availability of the range-extending engine could preclude drivers reserving battery charge to ensure they actually make it home.

The BEVx would have reduced performance while operating in APU (auxiliary power unit) mode—i.e., while using the range extender to find a charging location. Most of these vehicles are expected to have a zero-emission range of 80 miles or greater.

This vehicle has substantially more range than currently announced PHEVs, ARB staff noted, with electric range comparable to full function BEVs and will probably require ground-up BEV design.

Manufacturers believe that the APU will be a relatively high-cost option on top of an existing, full function (100+ mile), BEV. BEVs are expected to play an important role in ARB’s long-term emissions reduction strategy, but the market for current technology BEVs might be limited.

While the APU within the vehicle may evolve during this transition, from gasoline to advanced biofuels to hydrogen, it is reasonable to believe that this proposed vehicle may help meet ARB’s long-term GHG and criteria pollutant emissions reduction goals.

Staff expects BEVxs to play a longer-term role than TZEVs [ transitional zero emission vehicle; most commonly a plug-in hybrid PHEV] because of their improved zero emission mileage potential. These vehicles would be particularly well suited to use of low upstream GHG fuels that might be more expensive, since the predominant operating cost would be offset by relatively low-cost electricity. In addition to potential for emerging alternative fuel use, there is an opportunity to explore engine technologies that are advantageous but otherwise unsuitable for application in conventional vehicles.

Engine technology applied to existing PHEVs is derived from small conventional production gasoline engines, but highly specialized APUs for BEVxs may eventually spin off and evolve in completely different directions. Future BEVxs with highly specialized engine and fuel technologies could be optimized to drive cost, weight, size, and emissions down and make these specialized BEVx APUs suitable for more affordable and therefore more widespread application. Lotus Engineering and other automotive design firms have been developing hybrid-specific APUs and have several unique concepts under development already.


ARB staff suggested that the BEVx market may appeal to drivers who would not otherwise consider a BEV with the same range. Since staff considers these vehicles full function BEVs with short range APUs, it stressed the importance of having the minimum range for eligibility be equivalent to full function BEVs in the marketplace.

Basic criteria for these vehicle include:

  1. the APU range is equal to or less than the all-electric range;

  2. engine operation cannot occur until the battery charge has been depleted to the charge-sustaining lower limit;

  3. a minimum 80 miles electric range; and

  4. super ultra low emission vehicle (SULEV) and zero evaporative emissions compliant and TZEV warranty requirements on the battery system.

ARB expects—but is not at this point requiring— manufacturers to incorporate further performance limits on charge-sustaining APU mode operation, including speed restrictions.

For the 2012 through 2017 model years, BEVxs will be referred to as Type I.5x and Type IIx vehicles, to fit in with the pre-2018 nomenclature for ZEVs. Type I.5x and Type IIx vehicles will receive the same credits as Type I.5 and Type II ZEVs: 2.5 and 3 credits, respectively. Up to 50% of the portion of the ZEV requirement that must be met with pure ZEVs may be met with these Type I.5x and Type IIx vehicles.

ARB staff has committed to studying PHEV and BEVx user-behavior to find a more refined attribute-based methodology that can better correlate with desirable zero-emission VMT (vehicle miles traveled) and emissions reductions.


  • ARB Staff Report: Initial Statement Of Reasons Advanced Clean Cars 2012 Proposed Amendments To The California Zero Emission Vehicle Program Regulations



The lack of this sort of category is why CARB's original ZEV scheme failed.

CARB may be about to do it again with a minimum BEV range. The current sticking point with BEVs is the cost of the battery. There will be more all-electric miles with two vehicles with 40 miles of AER than one vehicle with 80 miles AER, and the sticker price will be a lot lower too. Last, the increased number of vehicles on the road means higher demand for chargers where people park, making that roll out faster also.


Maybe the Chevy Volt approach is the way to go for now. Of course they need to cut the size and weight in half and go to an all electric drive train. (Just like I said ten years ago).


The Th!ink car is small, light and all electric, but has not sold well. Maybe the market could and should decide this. If the marketing people were better at figuring out what the people really want and need, there would be less guess work.


Lack of imagination ...


It is the market driven idea, where the market is actually offered what it wants, a novel concept. Some might say YOU should buy an EV, but they won't. Once people realize that they can commute with an EV and save a lot of money, it could catch on.


There is definitely some portion of the population who would consider an BEV if they weren't worried about range anxiety.

This allows a whole new group to consider a BEV.

And it could also help a great deal in the cost for the short term. An 80 mile BEV is a lot cheaper than a 120 BEV. AT todays prices, that could save $4,000 on the price of the car making the BEV more affordable.


Cal. failed because most other States are too far behind and/or Cal. is too far ahead of the pack.


IMO ZEV and the EV failed in 2000 because Bush took the White House. GM realized that Bush would not support ZEV, they crushed the EV1s and sold off the batteries.

Once people see that they can commute with an EV and save a lot of money, they might say that we should have done this long ago. This is the realization by a large part of our population that will be necessary to put it over the top.


What is the point having 80 miles AER instead of 40 miles for BEx? In case you have charger at work place it will make no difference for electric miles driven. I think minimum for BEx qualiification should be carefully measured. IMHO the advantage BEx over EREV should be manufacturing cost due to lower complexity.


If someone could build a car like a Leaf with 20-25 Kw ICE range extender, you would have it.

It would be great as an EV and workable as an ICE. As long as you can cruise on the motorways at roughly the legal speed limit, you have it.

You could also reduce the battery size (say to 80 miles range) to save weight and cost (and make space for the generator, fuel, radiator etc.).


That makes sense to me, 8 kWh of batteries instead of 32 kWh. You save an extra 24 kWh, which is 6 cubic feet, 600 pounds. $12,000 and 80 miles extra range for a range extender of 2 cubic feet, 200 pounds, $4000 for an extended range of more than 400 miles.


SJC...the car you described is (almost exactly) the 2012/2013 Toyota-Prius PHEV. A very good interim solution, at least until such time (2020?) as batteries performances have doubled or tripled and the KWh price has dropped 3 times or so. The Prius 2012/2013 PHEV will serve you well till 2020+. Alternatively, a Camry or Lexus PHEV, with similar specs, will offer more room and comfort for an extra $10K to $25K or so.


I like the new Fusion hybrid, 40 mpg and mid sized. There are lots of good choices coming along. Now if we fill the tanks with synthetic fuel made from biomass, we will be way ahead of the game.


i think the government limits on range extenders is a mistake. the cost of running on electricity will be about one fourth of running on gasoline, so people will naturally run on electricity as much as possible. for the occasional trip that requires driving 250 or so miles, people will want the flexibility to do that, even if that happens once or less each month.


so basically a BEVx is an 80 mile range Volt, sulev rated but with only about 2 gallons of liquid fuel?.. even the Leaf is rated at 73 miles so it will need a slightly bigger pack.

I really dont see the point, the Volt's 40 mile range fits the need of a large majority of people and you dont have to fill up the gas tank if you dont want to. GM recommends you dont.

Someone explain the purpose behind this nonsense limitation..


What they're trying to do is avoid the cost, complexity and weight associated with the Volt.

Get rid of the highly complex planetary gear box, the relatively big 4 banger engine and anything that would add cost. Things like this:

They are hoping to find a way to make pure BEVs more acceptable by putting a very simple, very cheap charger on board.

I don't have a problem with their intent as it's not taking anything away from the Volt or Prius Plug-in. They have their own category in the CARB scheme so they are just creating yet another category they think may have value.

Whether they are right and whether it should be 40-50 mile AER vs 80 mile is another question.


You would have to ask them to explain, I do not think it is the responsibility for anyone on here to explain for these people.


I'm thinking that this may yet be another way to promote H2.. a mandated short range of only 80 miles on the low power range extender sounds like a small tank of H2 and a small fuel cell.


The cost of the fuel cell and hydrogen storage apparatus becomes even more ridiculously impractical if it is only used a fraction of the time. More batteries looks like a bargain by comparison.

An all-climate BEVx with something like a 2-cylinder opposed range extender burning LPG or DME (for zero evaporative emissions) would have unlimited range regardless of weather and be cheap to produce. Tubular fuel tankage could double as frame members.


I think that is more the idea. The range extender can be the 24 kW to 30 kW capacity and not the larger type for towing or climbing.

Drivers carry a lot of power that they probably do not need 99% of the time. That adds weight, complexity and cost. What they seem to be saying is a practical vehicle meets 99% of your requirements and you should reevaluate the other 1%.


People should have the choice to use much smaller, lighter on-board (genset) to extend the range of their PHEV to meet their limited needs. Whoever does not have to tow a trailer should not have to buy a vehicle (PHEV) that is built to do it.

Many small light weight PHEVs could go from A to Z with a smaller 7 to 10Kwh battery and a 10 KW genset.

Many mid-size lighter weight PHEVs could also to it with 10 to 15 Kwh battery and a 15 KW genset.


Micro, sub compact, compact, mid sized and even full sized could have a solution that would burn less fuel and create less pollution.

They have just created a category that allows car makers to consider this. If the market says sure, then they might just take a look at it. Once people make up their minds, the car makers will probably respond.

They certainly have choices, with all the makes and models available. There was a survey on CBS and 1/3 of the respondents said that they are considering buying a new car in 2012. That is a high number and if even close it would make a banner year for car sales coming up.


Mr Red Rose120

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