California ARB Staff Posts New Concept Paper for ZEV Amendments; Encouraging BEVs and PHEVs

10 November 2007

Among the amendments currently proposed by ARB staff is a method for calculating Equivalent All Electric Range to account for a variety of operating strategies for plug-in hybrid electric vehicles. The plot is an example of the application of the new formula. Click to enlarge.

The California Air Resources Board has posted a new concept paper outlining proposed amendments to the zero emission vehicle (ZEV) regulation. (Earlier post.) In developing the new proposals, staff started with the range of proposed amendments heard at the 24 July 2007 workshop, and considered comments received at the workshop and in dozens of subsequent meetings with affected stakeholders.

The new concept paper presents six, more refined amendment proposals—particularly in the area of plug-in hybrid electric vehicles (PHEVs)—as a starting point for further discussions with interested stakeholders and in preparation of the Initial Statement of Reasons and proposed amendments for the ZEV regulation.

The amendments cover: the Alternative Path to the ZEV requirement; the use of battery electric vehicles (BEVs) after 2008; hybrid electric vehicles, including PHEVs; neighborhood electric vehicles (NEV); timelines for intermediate volume manufacturers; and an extension of the travel provision that allows ZEVs placed in any state with the ZEV regulation to count in California.

Alternative Path. In 2003, the Board made its most recent amendments to the ZEV program, increasing the ZEV requirement to 16% in 2018. It also defined an alternative path for automaker compliance with the ZEV regulation that was solely designed to advance the commercialization of fuel-cell vehicles. Also, the credit system was adjusted so that one fuel cell vehicle garnered the same credits as 10 battery-electric vehicles.

Under the Alt Path, automakers are required to produce their sales-weighted market share of a target number of vehicles during four multi-year implementation phases. With fuel-cell vehicle development not proceeding as expected, ARB has been grappling with whether or not to ease the requirements.

Under the proposed amendment outlined in the November concept paper, ARB would maintain the 2,500-unit target for Phase II.

For Phase III, ARB would maintain the 25,000 target; establish a floor of 10% of those vehicles which must be either hydrogen fuel cell or battery electric ZEVS; and allow the remainder of the target to be met with a new category of “silver +” vehicles. Silver + vehicles are defined as high scoring (greater than one credit per vehicle) AT PZEVs that utilize fuel that can be used in a ZEV—e.g., plug-in hybrid electric vehicles (PHEV) and hydrogen internal combustion engine vehicles.

For Phase IV, the fuel cell/BEV floor would be set at 50% of the target of 50,000 ZEVs, and silver + vehicles would be allowed to fulfill the remaining 50 percent of the target.

ARB staff views the silver + vehicles as a more significant technology bridge to ZEVs than conventional AT PZEVs.

The requirement that they make use of a ZEV fuel significantly shifts the user towards the ultimate goal of electric drive using either batteries recharged from the grid or hydrogen. This is not an easy offset option for automakers. For most automakers it means an entirely new product that has not yet been demonstrated. In this sense, the silver+ option is highly technology forcing and at the same time incrementally more valuable as a bridge to pure ZEVs than silver vehicles.

A second proposal in this amendment area combines the Alternative and Base Paths into a “New Path” for Phase III and beyond that maintains the vehicle numbers. Staff is making this proposal to simplify the regulation, which most stakeholders, including staff and Board Members, are saying has become too complicated.

The New Path would return the compliance calculation to an annual percentage requirement for ZEVs with options to comply with percentages of PZEVs, AT PZEVs and a new AT PZEV plus or “silver+” category.

Battery Electric Vehicles. Another proposed amendment adjusts the credit ratio between full-function BEVs and hydrogen fuel cell vehicles. Rather than the existing 10:1 ratio, ARB staff is proposing a 1.33:1 ratio.

Hybrids and PHEVs. ARB staff is proposing several modifications to the hybrid electric vehicle (HEV) AT PZEV requirements, mostly to address plug in HEVs (PHEVs).

When the regulators first considered plug-in hybrids, they assumed that the vehicle would run in all-electric charge-depleting mode until the battery state of charge reached the designated threshold of depletion, and that the vehicle would then transition to operation on the engine and charge-sustaining mode.

Under a blended operating strategy, however, the engine may turn on before the depletion of the battery is complete—to assist with acceleration, top speeds or peak power requirements, for example. ARB staff is proposing retaining the same 10-mile minimum all electric range (AER)—now to be called Equivalent AER, EAER) for blended mode plug-ins as in the existing regulation.

The EAER takes the miles driven by the PHEV in charge-depleting mode and then adjusts those miles by the percentage of those miles operated electrically (Equivalent Electric Range Fraction or EERF). Staff further proposes that the EAER credit allowance be adjusted by a utility factor related to miles driven by consumers that normalizes the credit allowance to a maximum of the credit earned by a city electric vehicle. The proposed equations to govern calculation of the EAER credit allowance are:

EAER = R_cd * EERF

Allowance_AER = (EAER/ 50) * [(1-UF_Rcd)/ (1-UF₅₀)] * 1.45

Where:

• R_cd is the range of the PHEV in Charge Depleting mode
• EERF is the Equivalent Electric Range Fraction
• [(1-UF_Rcd)/ (1-UF₅₀)] adjusts for the lower probability that the blended PHEV will be driven far enough to make use of its stored electric energy and is from the 0-100 mile 4th order curve fit from SAE’s J1711, March 1999, page 52 which plots the likelihood of a vehicle being used to travel a daily range in miles,
• (EAER/ 50) normalizes the range allowance to a 50 mile range, the same as the minimum range for a Type I or City EV, and
• 1.45 is the assigned AER credit allowance because this is what a Type I ZEV would earn [2 credits – (0.2 PZEV base) – (0.35 Advanced Componentry allowance)] ≈ 1.45 AER allowance @ 50 miles.

ARB staff is also proposing to add a new, higher-power Type F HEV category that would meet a peak power requirement of 100 kW, or alternatively, when installed on AER-type PHEVs, would demonstrate sufficient power capability to propel an HEV through the entire UDDS driving test cycle on electric power alone.

The Type F HEV category is intended to encourage the deployment of HEV drive systems interchangeable with those deployed in full function ZEVs.

Staff is also proposing the elimination proposes to eliminate the low fuel-cycle emissions (LFCE) allowance for PHEVs and to increase the credit for AER PHEVs under the advanced componentry provision by at least 0.15 credits to recognize and compensate for the LFCE benefits of electric fuel. As a result of this proposed change, now only dedicated LFCE-fueled vehicles (e.g., compressed natural gas and hydrogen, depending on the source) will be eligible for AT-PZEV LFCE allowance.

Neighborhood Electric Vehicles. Staff proposes to increase the credit for neighborhood electric vehicles to 0.30 credits per vehicle, reflecting the vehicle’s positive benefits but limited functionality compared with full function battery electric or fuel cell electric vehicles.

ARB is encouraging stakeholders to meet with them between now and 28 November 2007 to further discuss these proposed amendments. Stakeholders may also provide comments on these topics in writing.

ARB plans the public release of the staff report on 11 January 2008, followed by a Board hearing in Sacramento 28-29 February 2008.

Resources

• ZEV Concept Paper November 2007