As transportation emissions reach critical levels in 2025, fleet operators are increasingly turning to renewable diesel alternative fuel as the most advanced biofuel solution available. Unlike traditional biodiesel, renewable diesel offers a true drop-in replacement that can transform your entire diesel fleet overnight without sacrificing performance or requiring infrastructure modifications.
This comprehensive guide covers everything you need to know about renewable diesel, from technical specifications and cost analysis to real-world implementation strategies. Whether you’re managing a municipal fleet, commercial trucking operation, or industrial equipment, understanding renewable diesel is crucial for meeting sustainability goals while maintaining operational excellence.
What is Renewable Diesel? Complete Technical Overview
Renewable diesel is a hydrocarbon fuel produced from renewable feedstocks such as vegetable oils, animal fats, and used cooking oil through advanced refining processes. Unlike biodiesel, renewable diesel is chemically identical to petroleum diesel, making it a true “drop-in” fuel that meets ASTM D975 specifications.
Scientific Definition and Chemical Composition
Renewable diesel consists of saturated hydrocarbons with carbon chain lengths typically ranging from C15 to C18. The fuel contains no oxygen molecules, unlike biodiesel, which gives it superior storage stability and cold-weather performance. The molecular structure is virtually identical to petroleum diesel, with the key difference being the renewable carbon source.
ASTM D975 Specification Compliance
Renewable diesel meets all requirements of ASTM D975, the standard specification for diesel fuel oils. Key specifications include:
- Cetane rating: 75-90 (compared to 48-52 for petroleum diesel)
- Sulfur content: Less than 15 ppm (ultra-low sulfur)
- Density: 0.78-0.82 g/cm³
- Flash point: Minimum 52°C
- Cold flow properties: Superior to petroleum diesel
Drop-in Fuel Characteristics and Benefits
The drop-in nature of renewable diesel provides several critical advantages:
- No blending required: Can be used at 100% concentration (R100)
- Infrastructure compatibility: Works with existing fuel systems, pipelines, and storage tanks
- Engine compatibility: Approved by major OEMs without warranty concerns
- Performance enhancement: Higher cetane rating improves combustion efficiency
Renewable Diesel Blend Designations
Renewable diesel blends are designated with an “R” followed by the percentage of renewable content:
- R100: 100% renewable diesel (pure form)
- R20: 20% renewable diesel, 80% petroleum diesel
- R5: 5% renewable diesel, 95% petroleum diesel
- B20R80: 20% biodiesel, 80% renewable diesel (100% biofuel)
Renewable Diesel vs. Biodiesel: The Critical Differences
Understanding the fundamental differences between renewable diesel and biodiesel is crucial for making informed fuel decisions. While both are derived from similar feedstocks, their production processes and resulting characteristics are dramatically different.
Production Process Comparison
| Aspect | Renewable Diesel | Biodiesel |
|---|---|---|
| Production Method | Hydrotreating (hydrogenation) | Transesterification |
| Chemical Structure | Saturated hydrocarbons | Fatty acid methyl esters (FAME) |
| Oxygen Content | 0% (no oxygen) | 10-12% oxygen |
| Energy Content | 96% of petroleum diesel | 93% of petroleum diesel |
Performance Characteristics Comparison
Cold Weather Performance: Renewable diesel maintains fluidity at much lower temperatures than biodiesel. While biodiesel can gel at temperatures as high as 34°F, renewable diesel typically performs well down to -10°F or lower.
Storage Stability: The absence of oxygen in renewable diesel prevents oxidation and extends storage life to over 12 months. Biodiesel, with its oxygen content, is more susceptible to degradation and typically requires use within 6-12 months.
Microbial Growth: Renewable diesel’s hydrocarbon structure makes it less susceptible to microbial contamination compared to biodiesel, which can support bacterial and fungal growth due to its ester composition.
Engine Compatibility and Warranty Coverage
Major engine manufacturers including Caterpillar, Cummins, Detroit Diesel, and Volvo have approved renewable diesel (R100) for use in their engines without voiding warranties. Biodiesel approvals are typically limited to B20 blends or lower, with some manufacturers requiring special maintenance protocols for higher blends.
Production Methods and Feedstocks
Hydrotreating Process Detailed Explanation
The hydrotreating process is the predominant method for renewable diesel production in the United States. This process involves:
- Feedstock Preparation: Raw materials are filtered and pretreated to remove impurities
- Hydrogenation: Feedstock is combined with hydrogen at high temperature (300-400°C) and pressure (30-100 bar)
- Catalytic Conversion: Metal catalysts facilitate the removal of oxygen and conversion to hydrocarbons
- Separation: Products are separated through distillation into renewable diesel, naphtha, and propane
- Finishing: Final treatment ensures fuel meets ASTM D975 specifications
Alternative Production Pathways
Gasification: Biomass is thermally converted to synthesis gas (syngas) and then catalytically converted to liquid hydrocarbons through Fischer-Tropsch synthesis.
Pyrolysis: Organic materials undergo thermal decomposition in the absence of oxygen, producing bio-oil that can be upgraded to renewable diesel.
Biological Sugar Upgrading: Uses engineered microorganisms to convert sugars directly into hydrocarbon molecules.
Feedstock Sources and Sustainability
Primary feedstocks for renewable diesel production include:
- Used Cooking Oil (UCO): 35-40% of total feedstock, collected from restaurants and food processing
- Animal Fats: 25-30%, including tallow from beef processing and poultry fat
- Soybean Oil: 20-25%, both virgin and waste streams
- Canola Oil: 5-10%, primarily from Canadian sources
- Other Oils: Including corn oil, palm oil, and emerging feedstocks like algae
U.S. Production Capacity and Facility Locations
As of 2025, the United States has renewable diesel production capacity of approximately 5.1-5.2 billion gallons annually across multiple operating facilities. Major production centers include:
- California: Multiple facilities with significant capacity from Phillips 66 Rodeo and Marathon Martinez conversions
- Louisiana: Diamond Green Diesel Norco facility with 982 million gallons capacity as the largest in the U.S.
- Texas: Diamond Green Diesel Port Arthur facility
- Other States: Facilities in North Dakota, Wyoming, Kansas, Washington, and Montana
Environmental Impact and Emissions Reduction
Greenhouse Gas Emissions Reduction
Renewable diesel delivers substantial greenhouse gas emissions reductions compared to petroleum diesel:
- Lifecycle GHG reduction: 60-95% depending on feedstock and production pathway
- California LCFS certified average: 65% carbon intensity reduction
- Used cooking oil pathway: Up to 85% GHG reduction
- Animal fat pathway: 75-80% GHG reduction
Air Quality Improvements
Independent testing has demonstrated significant reductions in criteria pollutants:
- Particulate Matter (PM): 34% reduction compared to petroleum diesel
- Nitrogen Oxides (NOx): 10% reduction
- Carbon Monoxide (CO): 12% reduction
- Hydrocarbons: 15% reduction
Lifecycle Carbon Intensity Analysis
The carbon intensity of renewable diesel varies significantly based on feedstock source and production methods:
| Feedstock | Carbon Intensity (gCO2e/MJ) | Reduction vs. Petroleum Diesel |
|---|---|---|
| Used Cooking Oil | 16.85 | 85% |
| Animal Fats | 27.9 | 75% |
| Soybean Oil | 40.2 | 65% |
| Petroleum Diesel | 110.9 | Baseline |
Economic Analysis: Costs, Pricing, and Market Dynamics
Current Pricing by Region (2025)
California Market: Renewable diesel pricing in California typically follows the cost of petroleum diesel, but becomes cost-competitive due to economic incentives provided by the state’s Low Carbon Fuel Standard. The LCFS support has made renewable diesel competitive with or even less expensive than petroleum diesel in many cases.
Outside California: Renewable diesel pricing ranges from $5.85-$6.50 per gallon in markets without Low Carbon Fuel Standard support, representing a $0.60-$1.25 premium over petroleum diesel.
California’s Low Carbon Fuel Standard Impact
California’s LCFS program provides economic incentives that make renewable diesel cost-competitive:
- LCFS Credit Value: $57-$75 per metric ton CO2e (down from previous highs due to oversupply)
- Credit Generation: 0.65 credits per gallon of renewable diesel
- Economic Benefit: $0.35-$0.50 per gallon cost offset
Federal and State Incentives
Renewable Fuel Standard (RFS): Renewable diesel generates D4 and D5 RINs worth approximately $0.70 per gallon depending on feedstock and market conditions.
Federal Tax Credits: The Second Generation Biofuel Producer Credit has been replaced by the 45Z clean fuel production credit starting in 2025, providing support for qualifying renewable diesel production.
State Programs: Oregon’s Clean Fuels Program and Washington’s Clean Fuel Standard provide additional market support in the Pacific Northwest.
Total Cost of Ownership Analysis
For fleet operators, total cost of ownership includes more than fuel price:
- Reduced maintenance: Higher cetane rating and superior lubricity can extend engine life
- DPF regeneration: Cleaner combustion reduces diesel particulate filter maintenance
- Cold weather reliability: Better low-temperature performance reduces operational disruptions
- Sustainability value: Meeting environmental goals without capital investment
Availability and Distribution Infrastructure
Geographic Availability
California Dominance: California consumes the majority of U.S. renewable diesel, with renewable diesel making up nearly 65% of California’s transportation distillate consumption in the third quarter of 2024. The state has over 570 retail fueling stations offering the fuel. The state’s supportive policy environment has created a mature market with reliable supply chains.
Expanding Markets: Other states showing growth include:
- Oregon: Biofuels comprised roughly one-quarter of the transportation distillate fuel used in the third quarter of 2024, with renewable diesel accounting for twice the share of biodiesel
- Washington: Biofuels accounted for 20% of the transportation distillate consumed in the second quarter of 2024, with renewable diesel contributing over 15%
- Idaho: Growing presence, primarily serving commercial fleets
- Montana: Focused on mining and agriculture sectors
Distribution Network and Logistics
Renewable diesel distribution leverages existing petroleum infrastructure:
- Pipeline compatibility: Can be transported through existing petroleum pipelines
- Terminal storage: Compatible with conventional diesel storage systems
- Truck delivery: Standard fuel delivery trucks can transport renewable diesel
- Retail dispensing: Uses existing diesel dispensers without modification
Real-World Fleet Implementation Case Studies
City of Oakland: Municipal Fleet Transformation
The City of Oakland has been using renewable diesel in its entire diesel fleet since fall 2015, making it one of the earliest large-scale adopters.
Implementation Details:
- Fleet Size: 650+ diesel vehicles and equipment
- Fuel Volume: 250,000 gallons annually
- Results: 1,500+ tons GHG reduction annually
- Cost Impact: Cost-neutral to slightly negative compared to petroleum diesel
Key Success Factors:
- Secured reliable local supplier (Golden Gate Petroleum)
- No infrastructure modifications required
- Comprehensive staff training on fuel benefits
- Regular monitoring of vehicle performance
Eugene Water & Electric Board: Utility Fleet Success
EWEB transitioned its entire diesel fleet to renewable diesel after experiencing limitations with biodiesel blends.
Implementation Highlights:
- Fleet Composition: 85 diesel vehicles including bucket trucks and heavy equipment
- Previous Experience: Used B20 biodiesel with cold weather and storage issues
- Transition Timeline: Complete conversion in 6 months
- Performance Results: Eliminated DPF regeneration alerts, improved cold weather reliability
New York City: Large-Scale Fleet Transition
NYC announced plans in 2023 to transition all 12,600+ heavy-duty diesel vehicles to renewable diesel by end of fiscal year 2024.
Program Scope:
- Vehicle Types: Garbage trucks, snow plows, fire apparatus, construction equipment
- Supply Strategy: Multi-vendor approach to ensure supply security
- Environmental Goal: 20% reduction in fleet GHG emissions
- Economic Considerations: Higher fuel costs offset by operational benefits
Private Sector Adoption
UPS: Testing renewable diesel in delivery fleet with positive results on engine performance and emissions reduction.
Major Carriers: Several large trucking companies have begun pilot programs, particularly for California operations where cost competitiveness is favorable.
Technical Specifications and Engine Compatibility
ASTM D975 Compliance Details
Renewable diesel meets or exceeds all ASTM D975 requirements:
| Property | ASTM D975 Requirement | Typical Renewable Diesel |
|---|---|---|
| Cetane Number | 40 minimum | 75-90 |
| Sulfur Content | 15 ppm maximum | Less than 1 ppm |
| Flash Point | 52°C minimum | 65-75°C |
| Cloud Point | Report requirement | -5 to -15°C |
Cetane Rating Advantages
The exceptionally high cetane rating of renewable diesel (75-90) compared to petroleum diesel (48-52) provides several benefits:
- Improved ignition: Shorter ignition delay for smoother combustion
- Reduced engine knock: Better combustion quality reduces stress on engine components
- Cold start performance: Easier starting in cold weather conditions
- Lower emissions: More complete combustion reduces pollutant formation
OEM Approvals and Warranty Coverage
Major engine manufacturers have approved renewable diesel use:
- Caterpillar: Approved R100 for all diesel engines
- Cummins: Full approval for renewable diesel in all applications
- Detroit Diesel: Approved for use without warranty concerns
- Volvo: Endorsed renewable diesel for all diesel engines
- Navistar: Approved R100 use in all diesel engines
Regulatory Landscape and Policy Support
Renewable Fuel Standard (RFS) Compliance
Under the federal RFS program, renewable diesel generates Renewable Identification Numbers (RINs):
- D4 RINs: For renewable diesel from waste feedstocks (used cooking oil, animal fats)
- D5 RINs: For renewable diesel from advanced biofuel feedstocks
- RIN Value: Approximately $0.70 per gallon based on current market conditions
- Compliance Role: Helps obligated parties meet advanced biofuel mandates
State-Level Clean Fuel Standards
California LCFS: The most mature and impactful program, providing credits based on carbon intensity reduction. Credits are tradeable and provide economic incentive for low-carbon fuels.
Oregon Clean Fuels Program: Similar to California’s LCFS, requiring fuel suppliers to reduce carbon intensity of transportation fuels by 20% by 2030.
Washington Clean Fuel Standard: Launched in 2023, targeting 20% carbon intensity reduction by 2034.
Federal Tax Incentives and Credits
45Z Clean Fuel Production Credit: Starting in 2025, this credit replaces previous biofuel tax credits and provides support for renewable diesel production based on carbon intensity reduction.
Alternative Fuel Infrastructure Credit: Supports installation of renewable diesel fueling infrastructure.
USDA Biofuel Infrastructure Partnership: Provides grants for renewable fuel infrastructure development.
Implementation Guide for Fleet Operators
Step-by-Step Transition Planning
Phase 1: Assessment and Planning (Months 1-2)
- Conduct fleet inventory and fuel consumption analysis
- Evaluate local renewable diesel availability and pricing
- Assess current fuel storage and handling infrastructure
- Review OEM warranties and approvals for your equipment
- Develop business case including costs, benefits, and ROI
Phase 2: Supplier Selection and Contracting (Months 2-3)
- Request proposals from multiple renewable diesel suppliers
- Evaluate supply reliability, pricing, and service capabilities
- Negotiate contracts with volume commitments and pricing terms
- Establish delivery schedules and emergency supply procedures
- Confirm fuel quality specifications and testing protocols
Phase 3: Implementation and Training (Months 3-4)
- Train maintenance staff on renewable diesel characteristics
- Educate drivers on fuel benefits and any operational changes
- Implement fuel quality monitoring procedures
- Begin transition with pilot vehicles or equipment
- Monitor performance and gather feedback
Supplier Selection and Contracting
Key Supplier Evaluation Criteria:
- Supply reliability: Consistent availability and delivery capability
- Fuel quality: ASTM D975 compliance and quality assurance programs
- Pricing structure: Competitive rates and transparent pricing mechanisms
- Geographic coverage: Ability to serve all fleet locations
- Technical support: Expertise in renewable diesel applications
Performance Monitoring and Optimization
Key Performance Indicators:
- Fuel economy: Monitor MPG changes compared to petroleum diesel
- Maintenance intervals: Track DPF regeneration frequency and engine maintenance
- Cold weather performance: Document starting reliability and operability
- Emissions tracking: Calculate GHG reduction achievements
- Cost analysis: Total cost of ownership including fuel and maintenance
Troubleshooting Common Issues
Storage and Handling:
- Ensure proper tank cleaning before first renewable diesel delivery
- Monitor fuel quality during extended storage periods
- Implement first-in, first-out inventory management
Cold Weather Operations:
- While renewable diesel has superior cold flow properties, consider fuel additives in extreme conditions
- Monitor cloud point and pour point in your specific climate
- Maintain heated storage where necessary
Future Outlook and Industry Trends
Production Capacity Expansion Plans
The renewable diesel industry is experiencing unprecedented growth:
- 2025 Capacity: 5.1-5.2 billion gallons annually
- 2027 Projected: 8.5 billion gallons with announced projects
- 2030 Target: 12+ billion gallons potential capacity
Major Expansion Projects:
- Diamond Green Diesel Norco expansion: Additional 400 million gallons
- Marathon Martinez conversion: 730 million gallons capacity
- Phillips 66 Rodeo conversion: 800 million gallons capacity
Technological Improvements and Innovations
Advanced Feedstocks: Development of algae-based and waste-to-fuel technologies will diversify feedstock sources and potentially reduce costs.
Process Optimization: Improved catalysts and process efficiency are reducing production costs and increasing yields.
Co-production Opportunities: Integration with sustainable aviation fuel production provides operational flexibility and improved economics.
Market Expansion Beyond California
Several factors are driving renewable diesel adoption outside California:
- State Clean Fuel Standards: Oregon, Washington, and potentially other states
- Corporate Sustainability Goals: Private fleets seeking emissions reductions
- Federal Policy Support: Potential expansion of federal incentives
- Cost Competitiveness: Improving economics as production scales
Long-term Sustainability Considerations
Feedstock Sustainability: Ensuring adequate waste feedstock supplies without competing with food production remains a key challenge.
Lifecycle Optimization: Continued focus on reducing carbon emissions through improved feedstock sourcing and production efficiency.
Market Integration: Better integration with existing fuel distribution systems and retail networks.
Frequently Asked Questions
Performance and Reliability
Q: Will renewable diesel affect my engine warranty?
A: No, renewable diesel is approved by all major engine manufacturers and will not void warranties when used according to specifications.
Q: How does renewable diesel perform in cold weather?
A: Renewable diesel has superior cold weather performance compared to both petroleum diesel and biodiesel, with cloud points typically 10-15°F lower than petroleum diesel.
Q: Do I need to modify my fuel system?
A: No modifications are required. Renewable diesel is compatible with all existing diesel fuel systems, storage tanks, and dispensing equipment.
Cost and Availability
Q: How much does renewable diesel cost compared to regular diesel?
A: In California, renewable diesel is cost-competitive with petroleum diesel due to LCFS support. Outside California, expect a premium of $0.60-$1.25 per gallon.
Q: Where can I buy renewable diesel?
A: Renewable diesel is widely available in California with over 570 stations. Availability is growing in Oregon, Washington, and other states. Contact local fuel distributors for commercial supply.
Environmental Impact
Q: How much do emissions really decrease?
A: Renewable diesel reduces lifecycle greenhouse gas emissions by 60-95% compared to petroleum diesel, depending on feedstock source.
Q: Is renewable diesel truly sustainable?
A: When produced from waste feedstocks like used cooking oil and animal fats, renewable diesel provides significant sustainability benefits without competing with food production.
As the transportation industry continues its evolution toward cleaner fuels, renewable diesel stands out as the most practical and effective solution available today. Its drop-in compatibility, superior performance characteristics, and substantial environmental benefits make it an ideal choice for fleets seeking immediate emissions reductions without operational disruption.
The continued expansion of production capacity, improving cost competitiveness, and growing policy support indicate that renewable diesel will play an increasingly important role in decarbonizing transportation. For fleet operators ready to take action on sustainability goals, renewable diesel offers a proven path forward that delivers results today while positioning for tomorrow’s regulatory requirements.
Just as businesses are embracing clean energy solutions like solar power to reduce their environmental impact, forward-thinking fleet operators are turning to renewable diesel as part of their comprehensive sustainability strategy. Companies exploring commercial solar solutions for their facilities often find that combining renewable electricity generation with renewable transportation fuels creates a powerful synergy for achieving carbon neutrality goals.
At SolarTech, we understand the importance of sustainable energy solutions across all sectors. While our expertise lies in solar energy systems, we recognize that true environmental stewardship requires a holistic approach to clean energy adoption, whether it’s powering buildings with solar panels or fueling fleets with renewable diesel.