Since its creation in 1967, the California Air Resources Board (CARB) has been at the forefront of U.S. air quality regulation, pioneering standards that protect public health and drive innovation across industries. What began as a response to smog and polluted air in Los Angeles has grown into one of the world’s most influential environmental regulatory agencies, shaping emissions rules not just in California, but nationwide.
A Brief History: Why CARB Was Created
California’s unique geography, booming population, and early smog episodes in the 1940s pushed leaders to seek stronger air pollution controls. In 1967, Governor Ronald Reagan signed the Mulford-Carrell Air Resources Act, unifying the Bureau of Air Sanitation and the Motor Vehicle Pollution Control Board into a single body now known as CARB. This gave the state authority, backed by the federal Clean Air Act, to establish more stringent air quality regulations than those at the national level.
Over the decades, CARB has implemented groundbreaking programs, from the first tailpipe emission standards to catalytic converter requirements and advanced clean car regulations.
What CARB Does: Mission & Function
CARB defines its mission is to “…to promote and protect public health, welfare, and ecological resources through effective reduction of air pollutants while recognizing and considering effects on the economy.” It does this through:
- Setting emissions standards for vehicles, engines, fuels, and consumer products.
- Developing and enforcing regulations limiting criteria pollutants (like NOx, CO, PM), toxic air contaminants, and greenhouse gases.
- Monitoring air quality and emissions inventories, such as through models like EMFAC.
- Certifying products and technologies to ensure they meet strict environmental criteria before they can be sold or used in California.
CARB also engages in incentive programs, technical research, and partnerships with federal, state, and local agencies to further clean air goals.
Industries and Products Affected by CARB
CARB has a vast regulatory reach affecting many economic sectors:
- Vehicles & Engines. Automakers must secure CARB certification for passenger cars, heavy-duty vehicles, motorcycles, and off-road equipment to prove they meet emissions standards (including greenhouse gases and smog-forming pollutants).
- Off-Road and Small Engines. Engines in lawnmowers, portable generators, and construction equipment are regulated, and many must be certified to meet emissions and evaporative standards.
- Consumer Products and Industrial Goods. Products that emit volatile organic compounds (VOCs) or other air pollutants fall under CARB’s purview. Examples include adhesives, paints, cleaning products, air cleaning devices, and composite wood products, often with specific emission limits or certification requirements.
- Aftermarket Parts and Accessories. Components that affect vehicle emissions (e.g., catalytic converters or engine control modules) require special verification and an Executive Order (EO) from CARB before legal sale or installation.
More recently, in June 2025 the federal government ended CARB’s EPA waiver enabling California to institute stricter emissions standards than federal limits. The action is focused on heavy-duty truck vehicles, zero emission vehicle requirements, and the Advanced Clean Cars II initiative, which would “…require that 100% of new passenger vehicles meet zero-emission standards (including plug-in hybrids) by the 2035 model year.”
CARB Certification: What It Means & Why It Matters
A CARB certification confirms that a product meets California’s strict emissions and performance standards before it can be sold or used in the state. Without this approval:
- Products cannot be legally offered or shipped into California (online or in stores).
- Businesses risk enforcement actions, including fines and forced product removal.
- Consumers may see advisories warning that products do not meet California requirements.
For example, portable and in-duct air cleaners sold in California must be CARB-certified for electrical safety and ozone emissions limits (≤50 ppb ozone), and products must bear a “Meets California ozone emissions limit: CARB certified” label.
How Companies Obtain CARB Certification for Products and Technologies
While specific requirements vary by product category, a typical certification process includes:
- Determine Applicability. Companies must first determine if their product falls under CARB’s regulations. For some categories, this involves product determination requests.
- Register or Pre-Apply. Many programs require manufacturers to register with CARB as a manufacturer and submit pre-application documentation.
- Testing. Products are tested to applicable standards (e.g., emission tests, safety checks) by CARB-approved or recognized laboratories. For air cleaners, for example, this means electrical safety and ozone testing.
- Submit Application & Documentation. Complete applications include test reports, labels, manuals, and detailed product information. CARB then reviews and issues certification or Executive Orders upon approval.
- Labeling and Recordkeeping. Once certified, products must be appropriately labeled and records maintained for compliance audits.
Each product category (like heavy-duty engines, consumer goods, vehicles) has its own detailed certification steps and ongoing reporting requirements.
If it wasn’t obvious already, suffice to say that CARB’s impact is far-reaching and comprehensive.
CARB and Behind-The-Meter in California
Businesses and commercial facilities in California are increasingly evaluating Behind-the-Meter (BTM) strategies for several reasons, including:
- Insultation from high and volatile energy costs. California ranks among the highest electricity prices in the U.S. TOU pricing and demand charges make costs unpredictable — and punishing for energy-intensive operations.
- Grid reliability gaps. Electricity and gas prices are unpredictable. Facilities with no on-site generation absorb every rate spike with no hedge.
- Electrification load growth. Operations tied entirely to the grid are vulnerable to outages and capacity constraints during peak demand.
- Emissions and permit pressure. CARB and local air districts impose strict emissions standards.
- Interconnection backlogs. New utility service or capacity upgrades can take 18–24 months or more in California. BTM generation bypasses interconnection queues entirely.
- Expansion constraints. Growing facilities waiting on utility upgrades lose competitive ground. BTM power scales on your timeline, not the utility’s.
For any one or combination of these reasons, BTM is becoming a more attractive alternative than grid reliance.
Futureproofing Your BTM Strategy
Additionally, BTM planners need to be cognizant of how future regulations impact their BTM options. Two rulemaking processes having implications for BTM strategies include:
- Tier 5 rulemaking. For example, CARB is currently drafting potential changes to the off-road diesel engine standards, which they call Tier 5 rulemaking. Tier 5 rulemaking would tighten NOx and particulate matter (PM) emission limits for new off-road compression-ignition (CI) engines beyond what current Tier 4 Final standards allow.
- SB 253/261 GHG disclosure. SB-253 requires companies subject to California’s new greenhouse gas disclosure rules are required to annually disclose their scope 1, 2, and 3 GHG emissions for the prior fiscal year. Companies subject to SB-261 will require companies to publish biennial climate-related financial risk reports. Both programs are currently under development by CARB.
Organizations considering BTM options are advised to stay current with these developing rules, as they may have implications for their facilities. For example, Tier 5 engine requirements may require BTM power systems to replace diesel backup generators with lower-emission alternatives.
READ MORE: FlexEnergy Solutions Secures CARB Recertification of GT333S Flex Turbine
FlexEnergy Natural Gas Turbines Are CARB Certified and Thrive in California
Given the complexity of California’s air quality and climate laws, it’s important to choose a partner knowledgeable and experienced working in the state. That’s where FlexEnergy comes in.
The Flex Turbine® is CARB Certified. CARB does not “certify” natural gas turbine engines as a sector but does regulate their emissions pursuant to distributed generation (DG) technologies via Executive Order (EO).
The GT333S Flex Turbine recently gained recertification by CARB in 2025 (EO DG-045). This milestone marks ten consecutive years of emissions compliance under California’s stringent distributed generation standards. This ensures that the GT333S continues to be fully eligible for installation and operation in California.
California Behind-the-Meter Case Studies
One of Hollywood’s Original Studio Saves $20,000 a Day in Energy Costs. One of Hollywood’s original film studios was running a 24/7 production operation across a sprawling Los Angeles campus — with energy bills to match. California’s peak-demand pricing was making grid power the production’s most unpredictable cost. The studio needed reliable on-site power that could support continuous production schedules without interruption or surprise charges.
CASE STUDY | Hollywood Studio: On-Site Power Generation Saves Hollywood Studio $20,000 Daily
Applied Medical Resources Goes Behind-The-Meter for Precision Manufacturing. Applied Medical Resources manufactures precision medical devices in Orange County — a process where power quality is as critical as power availability. Even brief voltage fluctuations can damage sensitive equipment or disrupt sterile manufacturing environments. With California’s grid becoming less predictable, AMR turned to FlexEnergy Solutions for on-site generation that matched the precision of their manufacturing process.
CASE STUDY | Applied Medical Resources: High-Reliability Power with Low Environmental Impact
Final Thoughts on CARB Compliant Power
CARB is a powerful force in environmental regulation, shaping how products are designed, manufactured, and used, not only in California but across the U.S. Its certification programs are essential checkpoints for companies in regulated industries.
Whether you are planning a Behind-the-Meter or Combined Heat & Power (CHP) system for reliable and clean manufacturing, facility heating and cooling, district power, or commercial building applications in California, understanding CARB is critical to successfully operating in the state. Top of Form
The good news is that FlexEnergy Solutions has CARB certified solutions ready to meet your power and CHP needs.
If your facility operates in California, or plans to, now is the time to evaluate BTM and CHP solutions already proven under CARB’s strict standards. Talk with FlexEnergy Solutions to see how a CARB-certified Flex Turbine powered system can reduce emissions, cut energy costs, and deliver dependable on-site power without long grid delays.