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CARB At-Berth Regulation

The California Air Resources Board (CARB) At-Berth Regulation is the United States’ most stringent in-port emissions control rule for ocean-going vessels (OGVs), requiring vessels visiting designated California ports to reduce their at-berth NOx and PM₂.₅ emissions through one of three approved pathways: connection to shore power (cold ironing), use of an approved capture-and-control (CAC) technology such as the Advanced Maritime Emissions Control System (AMECS), or an approved alternative compliance plan. The original rule under California Code of Regulations Title 17 §93118.3, adopted in December 2007 and operative from 1 January 2014, applied to container, refrigerated cargo and cruise vessels at the six largest California ports. The 2020 amendments (operative from 1 January 2023 onwards in stages) expanded the scope to cover ro-ro and tanker vessels, increased the compliance percentage from 80% to 90% by 2027, and tightened verification and reporting requirements. Compliance is enforced by CARB’s Enforcement Division through annual reporting, on-site inspections and a penalty regime that can reach approximately USD 75,000 per non-compliant visit. The regulation has driven the build-out of shore-power infrastructure at all six major California ports (Los Angeles, Long Beach, Oakland, Hueneme, San Diego, San Francisco) and has been credited with reducing port-area NOx by approximately 80% and PM₂.₅ by approximately 75% over the period 2014 to 2024 according to the 2024 CARB Emissions Inventory for Ocean-Going Vessels. ShipCalculators.com hosts the principal computational tools: the CARB at-berth compliance calculator implements the regulation-specific compliance check; the cold ironing / OPS offset calculator quantifies the per-visit emissions reduction; the shore power required cable size calculator supports the electrical engineering side of shore-side connections; and the HVSC 6.6 / 11 kV system calculator implements the IEC/IEEE 80005-1 connection design. A full listing is available in the calculator catalogue.

Contents

Background and history

California air quality crisis (1970s to 2000s)

The Los Angeles basin and the San Francisco Bay area have long ranked among the most polluted air-quality regions in the United States. The 1970 federal Clean Air Act and the parallel California Health and Safety Code Section 39000 series established California’s authority to set vehicle emissions standards stricter than the federal baseline (a unique federal preemption waiver granted to California by section 209 of the Clean Air Act, in recognition of the state’s pre-existing air-quality regulatory regime).

By the mid-1990s, despite substantial progress on land-side vehicle emissions, the South Coast Air Quality Management District identified that goods movement through the ports of Los Angeles and Long Beach was the single largest remaining source of NOx and PM₂.₅ in the basin. The two ports together handled approximately 40% of all US containerised imports through the 2000s and contributed an estimated 15% of basin-wide NOx and 25% of basin-wide directly-emitted PM₂.₅. A significant fraction of these emissions came from ocean-going vessels at berth, with auxiliary engines running continuously to power cargo operations, refrigeration, lighting, ventilation and crew accommodation while the ship was alongside.

2005 Goods Movement Action Plan and the 2006 ARB inventory

In April 2005 the California Environmental Protection Agency and the Business, Transportation and Housing Agency published the Goods Movement Action Plan, identifying ocean-going vessel emissions as a priority intervention area. The 2006 ARB Goods Movement Emissions Reduction Plan set a target of 85% reduction in OGV-source NOx by 2020 and an 80% reduction in OGV-source PM₂.₅ by 2014, against the 2005 baseline.

The Plan recognised three available compliance technologies for at-berth emissions:

  • Shore power (also known as cold ironing or alternative maritime power, AMP): connecting the ship to a shore-side electrical supply so the on-board diesel auxiliary engines can be shut down.
  • Low-emission diesel auxiliary engines with after-treatment (selective catalytic reduction, diesel particulate filter).
  • Capture-and-control (CAC) technologies that capture exhaust gas at the funnel and treat it ashore before discharge.

The Plan recommended that California adopt a regulation requiring use of one of these technologies for a defined percentage of vessel visits.

2007 original CARB at-berth rule

The original CARB At-Berth Regulation was adopted by ARB on 6 December 2007 and operative from 1 January 2014. The rule:

  • Applied to container, refrigerated cargo and cruise vessels of 5,000 GT and above visiting the six designated California ports.
  • Required fleet-level compliance (a vessel operator’s fleet must achieve the percentage threshold across all visits, not each individual visit).
  • Phased the compliance percentage: 50% by 2014, 70% by 2017, 80% by 2020.
  • Allowed the three compliance pathways (shore power, CAC, alternative compliance plan).
  • Established the Vessel of Special Use (VSU) exemption for ships unable to comply due to operational constraints (e.g. military, research, salvage).

The original rule drove substantial shore-power infrastructure investment at California ports. By 2014, shore power was operational at the dominant container terminals at Los Angeles and Long Beach; by 2017, all six ports had operational shore power for container and cruise vessels.

2020 amendments: scope expansion and tightening

CARB conducted a comprehensive rule review in 2018 to 2020, concluding that:

  • The original 80% target by 2020 had been largely achieved but with significant compliance heterogeneity across operators.
  • Expansion to ro-ro and tanker vessels was technically feasible.
  • Further tightening to 90% by 2027 was achievable with extended phase-in and additional CAC technology development.
  • The CAC compliance pathway needed clarification to enable wider adoption (the original rule was perceived as favouring shore power).

The amendments were adopted on 27 August 2020 and operative from 1 January 2023 in stages. The principal changes:

ChangeOriginal rule2020 amendments
Vessel categoriesContainer, refrigerated cargo, cruise+ ro-ro, tanker
Container/refer/cruise compliance80% by 202090% by 2027
Ro-ro compliancen/a80% by 2025, 90% by 2027
Tanker compliancen/a80% by 2027, 100% by 2030
CAC technology approvalOne technologyMultiple approved technologies
ReportingAnnual fleet reportsAnnual + per-visit
PenaltiesUSD 8,000 to 50,000 per visitUSD 25,000 to 75,000 per visit
Vessel of Special UseLimitedExpanded definition

The expansion to tanker vessels was the most controversial element: tanker operators argued that the unique safety considerations of tanker cargo operations (vapour recovery, inert gas systems, fire-fighting standby) made shore-power connection technically difficult. CARB responded by allowing a longer phase-in (compliance not required until 2027) and explicitly approving CAC as the preferred tanker compliance pathway.

Regulatory basis

17 CCR §93118.3

The operative regulation is set out in California Code of Regulations Title 17, Subchapter 7.5 (Airborne Toxic Control Measures), Section 93118.3 Control Measure for Ocean-going Vessels At Berth. The text is approximately 60 pages of regulatory detail covering:

  • Definitions (vessel categories, port boundaries, “at berth” definition, “visit” definition)
  • Compliance options (shore power, CAC, alternative compliance plan, VSU)
  • Phased compliance percentages by vessel type and year
  • Verification, reporting and recordkeeping requirements
  • Enforcement and penalties
  • Vessel of Special Use exemption procedure

The regulation is implemented and enforced by CARB’s Enforcement Division (under the Air Quality Officer authority of California Health and Safety Code §41650) in cooperation with the California Highway Patrol (which provides on-site inspection support at port entry points).

Federal Clean Air Act preemption

The CARB at-berth rule operates under California’s special federal Clean Air Act waiver (section 209). The rule has been challenged in federal court multiple times by shipping industry groups arguing federal preemption; the courts have consistently held that California’s emergency air-quality powers extend to in-port emissions and that the rule does not violate the dormant Commerce Clause.

The most significant challenge was Pacific Merchant Shipping Association v. Goldstene (9th Cir. 2014), in which the court upheld the rule against a Commerce Clause challenge. The 2020 amendments were similarly challenged in World Shipping Council v. CARB (2022), with the Ninth Circuit again upholding the rule.

Coastal Commission overlap

Shore-power infrastructure construction at California ports is also subject to California Coastal Commission permitting under the California Coastal Act (Public Resources Code §30000 series). The Coastal Commission has consistently supported shore-power infrastructure but requires environmental impact assessment for substantial new electrical substations.

Scope and applicability

California ports covered

The regulation applies at six California ports:

PortContainer terminalsCruise terminalsTanker / ro-ro terminals
Los Angeles (POLA)All majorYesYes
Long Beach (POLB)All majorn/aYes
Oakland (POAK)All majorn/aSome
Huenemen/an/aReefer + ro-ro
San Diegon/aYesYes
San Franciscon/aYesn/a

Other California ports (Stockton, Sacramento, Eureka, Humboldt) are not currently designated under the regulation, although they may be added in future amendments.

Vessel categories

The regulation covers ocean-going vessels of 5,000 GT and above in five categories:

  • Container vessels: any vessel designed primarily for the carriage of containerised cargo. Compliance from 2014.
  • Refrigerated cargo vessels (reefers): vessels with installed refrigerated cargo capacity. Compliance from 2014.
  • Cruise vessels: passenger vessels designed for cruise tourism, capacity > 100 passengers. Compliance from 2014.
  • Ro-ro vessels (including ro-pax): vessels designed for the roll-on/roll-off carriage of vehicles or trailers. Compliance from 2025.
  • Tanker vessels: vessels carrying liquid cargo in bulk (oil, chemical, LNG/LPG). Compliance from 2027.

Visit threshold

A vessel is subject to the regulation when it makes a “visit” to a covered port, defined as a stay at berth of more than 2 hours. Visits of less than 2 hours are exempt. Vessels making fewer than 5 visits per calendar year to California ports are subject to a relaxed compliance regime (typically 50% rather than the standard percentage).

Compliance pathways

Shore power (cold ironing)

Shore power (also known as alternative maritime power, AMP, or cold ironing) is the dominant compliance pathway for container and cruise vessels. The technology:

  • Provides a high-voltage electrical connection from a port-side substation to the vessel’s main bus.
  • Standard voltages: 6.6 kV, 11 kV (per IEC/IEEE 80005-1).
  • Required cable: typically 350 to 750 mm² copper, with shore-side termination at a single connection point on the vessel.
  • The vessel’s main electrical system switches over from auxiliary engines to shore power, allowing the auxiliary engines to be shut down.
  • Connection time: typically 15 to 30 minutes per arrival, 15 to 30 minutes per departure.

The shore power required cable size calculator implements the cable-sizing calculation per IEC 60364 and IEEE 80005-1; the HVSC 6.6 / 11 kV system calculator implements the connection design. The cold ironing / OPS offset calculator quantifies the emissions reduction achieved.

Shore power requires the vessel to have an installed shore-power connection. Container and cruise newbuildings since approximately 2010 typically include shore-power capability as a standard feature; older vessels may require retrofit (typical retrofit cost USD 0.5 to 2 million per vessel).

Capture-and-control (CAC) technology

Capture-and-control technologies capture the vessel’s exhaust gas at the funnel and treat it ashore before discharge. The principal approved CAC technology in California is the Advanced Maritime Emissions Control System (AMECS) developed by Advanced Cleanup Technologies Inc. (ACTI) and Tri-Mer Corporation. AMECS:

  • Uses a barge-mounted exhaust capture hood positioned over the vessel funnel.
  • Pumps the captured exhaust gas through a multi-stage treatment system: SCR for NOx, scrubber for SOx, fabric filter for PM.
  • Achieves typical 90% to 95% reduction in NOx and 90%+ reduction in PM₂.₅.
  • Operating cost approximately USD 5,000 to 12,000 per vessel visit.
  • Suitable for vessels without installed shore-power capability and for vessel categories where shore power is technically difficult (especially tankers).

CARB has approved AMECS for use at the Port of Long Beach since 2018 and has additional approvals pending for Los Angeles and Oakland.

Alternative compliance plan

A vessel operator may submit an Alternative Compliance Plan (ACP) to CARB demonstrating that an alternative technology achieves equivalent emissions reduction. Approved alternatives have included:

  • Hybrid auxiliary engines with significant after-treatment (SCR + DPF + scrubber) achieving 80%+ NOx and PM reduction.
  • Battery-hybrid auxiliary systems that can run on stored battery power for the duration of a typical port stay.
  • LNG-fuelled auxiliary engines with low NOx and zero SOx emissions.

ACPs are reviewed on a case-by-case basis and require CARB approval before implementation.

Vessel of Special Use exemption

Vessels meeting one of the following criteria may be exempt from compliance:

  • Government vessels (military, Coast Guard, NOAA research)
  • Salvage and emergency response vessels
  • Vessels in distress requiring repair
  • Vessels arriving on first commercial voyage (one-time exemption)
  • Vessels with cargo operations of less than 2 hours
  • Vessels with documented technical inability to comply (subject to annual review)

The VSU exemption is documented in the vessel’s annual compliance report and is subject to CARB audit.

Compliance trajectory

The phased compliance trajectory by vessel type and year:

Vessel type2014201720202023202520272030
Container50%70%80%80%85%90%90%
Refrigerated cargo50%70%80%80%85%90%90%
Cruise50%70%80%80%85%90%90%
Ro-ron/an/an/a50%80%90%90%
Tankern/an/an/a50%70%80%100%

The percentage is calculated at the fleet level for the vessel operator: total qualifying visits / total visits to California ports per year. A vessel operator that achieves 95% on container and 75% on cruise meets the 80% requirement on average but may fail the 90% specific requirement once it reaches 2027. Operators typically run dedicated compliance teams to monitor the running percentage and ensure all visits are compliant.

Shore power infrastructure

The build-out of shore-power infrastructure at California ports has been a major capital project, with cumulative investment of approximately USD 600 million through 2024. Per-port summary:

Port of Los Angeles (POLA)

  • Shore power capacity: 28 berths across the major container terminals (TraPac, Yusen, Pier 400, Yang Ming, China Shipping, APMT, West Basin, Trapac West, Trapac East, Husky, etc.).
  • Cruise terminal: World Cruise Center with 3 berths.
  • Substation capacity: ~120 MW total connected.
  • Annual visits using shore power (2024): ~3,400.

Port of Long Beach (POLB)

  • Shore power capacity: 22 berths across major container terminals (LBCT, ITS, SSA, Pacific, Total Terminals, Pier T).
  • AMECS barge: stationed at Pier T for vessels without installed shore power.
  • Substation capacity: ~95 MW total connected.
  • Annual visits using shore power (2024): ~3,100.

Port of Oakland (POAK)

  • Shore power capacity: 14 berths across container terminals (TraPac, OICT, SSA Marine, Trapac).
  • Substation capacity: ~55 MW total connected.
  • Annual visits using shore power (2024): ~2,400.

Smaller ports

  • Hueneme: 2 berths for refrigerated cargo and ro-ro.
  • San Diego: 1 cruise berth and 1 reefer berth.
  • San Francisco: 1 cruise berth.

Penalties and enforcement

Annual reporting

Vessel operators must submit an annual compliance report to CARB by 1 March of the following year, covering:

  • Total visits to each California port.
  • Compliance status of each visit (shore power / CAC / VSU / non-compliant).
  • Total energy consumed per visit.
  • Total emissions reduction calculation per visit.

Reports are submitted through CARB’s online Vessel Reporting Database. The CARB at-berth compliance calculator implements the per-visit compliance check and the fleet-level percentage calculation.

On-site inspection

CARB Enforcement staff conduct on-site inspections at California ports, typically:

  • 100% of vessels arriving at high-priority terminals (Los Angeles, Long Beach container).
  • 50% of vessels at other terminals.
  • 100% of vessels with prior compliance issues.

Inspections cover: visual confirmation of shore-power connection, electrical metering verification, CAC equipment operation, VSU documentation review.

Penalties

The 2020 amendments significantly increased penalties:

  • First offence: USD 25,000 per non-compliant visit.
  • Repeat offence: USD 50,000 per visit.
  • Pattern of non-compliance: USD 75,000 per visit + supplemental administrative penalty.
  • Wilful misreporting: criminal referral to the California Attorney General.

Total enforcement penalties collected by CARB through 2024: approximately USD 12 million across approximately 250 vessels. The 2024 CARB Annual Enforcement Report identifies 95% fleet compliance (vs the 90% regulatory threshold) as the current operational state.

Comparison with EU and IMO regimes

DimensionCARB At-BerthEU MRV / EU ETSIMO MARPOL Annex VI
Geographic scope6 California portsEEA portsGlobal
PollutantsNOx, PM₂.₅ at berthCO₂ (CH₄, N₂O from 2026) per voyageSOx, NOx, PM (Reg 14, 13) + CO₂/CH₄/N₂O (Reg 22+, GFI from 2027)
Compliance mechanismShore power / CAC / ACP at portAllowance surrender; intensity reductionFuel-content / engine-cert / WtW intensity
Scope of obligationAt-berth emissions onlyPer-voyage emissionsPer-voyage + at-berth
Threshold size5,000 GT5,000 GT (400 GT for some types from 2025)400 GT (Annex VI) / 5,000 GT (DCS, EEXI, CII)
EnforcementCARB inspection + reportingEMSA / Member State PSCFlag state + PSC + IMO audit
PenaltyUSD 25-75k per visitEUA price × allowances + finesDetention + fines (varies by Member State)

The CARB rule is complementary to EU and IMO regimes: a vessel calling at a California port must comply with all three simultaneously. For container shipping on the trans-Pacific to US East Coast route via Panama, the typical compliance burden in 2025 is approximately USD 1.5 to 3 million per year per vessel (CARB ~USD 200k from shore power costs + EU ETS ~USD 800k + FuelEU ~USD 200k + IMO Net-Zero from 2027 ~USD 1.5M).

Future outlook

The principal regulatory developments expected through 2030 are:

  • 2025 (1 January): ro-ro vessels enter the regulation at 80% compliance.
  • 2027 (1 January): tanker vessels enter at 80% compliance; container/cruise/reefer move to 90%; ro-ro to 90%.
  • 2027 onwards: review of CAC technology approvals; potential expansion to additional vessel categories (general cargo, bulk).
  • 2030 (1 January): tanker compliance to 100%.
  • 2030 onwards: integration with California’s broader Advanced Clean Fleets regulation (which addresses goods movement vehicles); potential expansion to additional California ports (Stockton, Sacramento, Eureka).
  • 2035 onwards: CARB has proposed a long-term Zero-Emission At-Berth target requiring all OGV at-berth power to come from zero-emission sources (shore power from renewables, hydrogen fuel cells, or onboard battery operation only). Final rule adoption expected 2027 to 2028.

The regulation has driven the build-out of shore-power infrastructure at California ports and has contributed to the broader US adoption of shore power: ports of Seattle, Tacoma, New York/New Jersey, Savannah and Houston have all implemented shore power for container and cruise vessels (typically voluntary or under local-port rules) following the California precedent.

See also

References

  1. California Air Resources Board. Control Measure for Ocean-going Vessels At Berth, 17 CCR §93118.3, original adopted 6 December 2007, amended 27 August 2020.
  2. California Air Resources Board. Initial Statement of Reasons for Proposed Rulemaking: Control Measure for Ocean-going Vessels At Berth (Amended). CARB, Sacramento, May 2020.
  3. California Air Resources Board. Final Statement of Reasons for Adopted Amendments: Ocean-going Vessels At Berth. CARB, Sacramento, December 2020.
  4. California Air Resources Board. 2024 Emissions Inventory for Ocean-Going Vessels. CARB, Sacramento, 2024.
  5. California Air Resources Board. Annual Enforcement Report 2024. CARB Enforcement Division, Sacramento, 2024.
  6. California Environmental Protection Agency. Goods Movement Action Plan. CalEPA, Sacramento, April 2005.
  7. California Air Resources Board. Goods Movement Emissions Reduction Plan. CARB, Sacramento, 2006.
  8. Pacific Merchant Shipping Association v. Goldstene, 9th Circuit Court of Appeals, decided 30 January 2014.
  9. World Shipping Council v. CARB, 9th Circuit Court of Appeals, decided 12 October 2022.
  10. Port of Los Angeles. Shore Power Annual Report 2024. POLA, Los Angeles, 2024.
  11. Port of Long Beach. Clean Air Action Plan Annual Update 2024. POLB, Long Beach, 2024.
  12. Port of Oakland. Shore Power Implementation Status Report. POAK, Oakland, 2024.
  13. International Electrotechnical Commission. IEC/IEEE 80005-1:2019 - Utility connections in port - Part 1: High Voltage Shore Connection (HVSC) Systems - General requirements. IEC, Geneva, 2019.
  14. Pacific Merchant Shipping Association. 2024 Industry Compliance Survey. PMSA, San Francisco, 2024.

Further reading

  • CARB. Shore Power Implementation Guide for OGV Operators. CARB, Sacramento, 2024.
  • CalSTA. California Sustainable Freight Action Plan: Update 2024. California State Transportation Agency, Sacramento, 2024.
  • C40 Cities Climate Leadership Group. Green Ports Forum: California Lessons Learned. C40, London, 2023.