The California Air Resources Board (CARB) is near to codifying the Advanced Clean Fleets (ACF) Regulation, which CARB Board Members have described as perhaps the most prescriptive, far-reaching regulation put forward in its history. Essentially, the ACF regulation requires a swift and complete shift from conventional vehicles to Zero-Emission Vehicles (ZEV). This transition raises several significant questions for water agencies, and other fleet operators. Are there affordable vehicle options that will meet the varied needs of the fleet? What are the cost implications for the charging equipment and electricity that will be needed? What kinds of changes will need to be implemented in operating and maintaining these ZEVs? Are there funding sources and programs that can support fleets in making this transition? In this brief article, we will summarize this new proposed regulation, and address some of the key implications for water agencies and their fleets.

CARB’s Proposed Advanced Clean Fleet Regulation

Beginning in January of 2024, CARB’s proposed ACF regulation will require that 50% of all newly acquired fleet vehicles be zero-emission, with few exceptions. Beginning in 2027, all newly acquired vehicles must be zero-emission. And by the 2040 model year, all new sales medium and heavy-duty vehicles must be zero-emission. Exceptions generally relate to the operational purpose and availability of the vehicle itself and fueling infrastructure. Several exception categories are defined, but precise criteria are not defined. Each request for exception will be evaluated and decided by the CARB on a case-by-case basis.

To establish a baseline that CARB can effectively monitor, fleet managers will be required to provide a complete list and description of all vehicles in the current fleet by April of 2024. In accordance with CARB’s new “reporting and recordkeeping” requirements, reports must be submitted annually. Proceedings regarding the ACF regulation are still underway. A hearing was conducted October 27, 2022. Hundreds of written and verbal comments have been collected and are currently under consideration by the Board. Although a final vote by CARB on the proposed regulation isn’t scheduled, it is expected that regulation will be approved by early next year. The latest version of the proposed regulation can be found here.

Implications for Water Agencies

Assuming the proposed regulation is codified as proposed, water agencies (and other fleet operators) will need to begin reporting to CARB by January of 2024. Agencies will need to be prepared to comply with the 50% ZEV purchase requirement beginning in 2024 and the 100% ZEV purchase requirement by 2027. In preparation for this transition, a detailed assessment of several items will be necessary:

  • Your Current Fleet – What are the current vehicle functional categories and duty- and drive-cycles of your agency’s vehicle fleet, and how much energy do they consume during typical drive cycles? How far out are vehicles expected to be replaced? How soon will additional vehicles be needed?
  • Available ZEV Vehicle Options – What options are currently available to meet both the vehicle and ancillary equipment needs of your current fleet? What are the costs?
  • Charging Needs – How much energy will your electrified fleet need, and at what power level? What kind of charging infrastructure will be needed, how many will you need and where should they be installed? How much will the equipment and the electricity cost?
  • Funding Sources – What kinds of incentives and programs are available to support agencies as they make this transition?

TerraVerde Can Support Your Agency With Developing A Compliance Plan

TerraVerde Energy is an independent energy consulting firm proudly supporting California public agencies since 2009 and serves as ACWA’s Preferred Provider for fleet electrification planning services. As your agency looks to identify the path forward, TerraVerde can provide your agency with a clear, actionable assessment of your options, costs, challenges, and opportunities; enabling your team to take an intelligent, risk-mitigated approach to fleet electrification. We would welcome the opportunity to meet with your team and discuss your fleet electrification planning needs. Write to us at to get started today.

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