# Renewable diesel and SAF: Techniques

HEFA rules today; gasification and alcohol-to-jet are still first plants

Source page: https://www.materialinsights.org/energy/hvo_saf/techniques/

What this tab covers The methods used to capture this energy: how each works, and how they compare on efficiency, cost, life-cycle emissions, maturity and scale.

SAF reached about 1.9 million tonnes (2.4 billion litres) in 2025, 0.6% of jet fuel use, mostly from HEFA plants that also make renewable diesel. Gasification, alcohol-to-jet and co-processing are at first-plant stage.

#### Comparison

| Method | Efficiency | Cost | Life-cycle emissions | Maturity | Scale |
|---|---|---|---|---|---|
| **HEFA renewable diesel (HVO)**^[1](https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2021/Jul/IRENA_Reaching_Zero_Biojet_Fuels_2021.pdf)^[3](https://eur-lex.europa.eu/eli/dir/2018/2001/oj)^[4](https://www.eia.gov/biofuels/update/table1.pdf)^[5](https://www.iea.org/reports/renewables-2025/renewable-transport) | 80-85% of output is diesel when jet is 15-20% (calculated) | Feedstock is about 80% of total cost | EU typical savings: rapeseed 51% (about 46 g CO2eq/MJ, calculated), waste cooking oil 87% (about 12), palm with open effluent ponds 34% (about 62) | mature | US renewable diesel capacity 4,989 million gallons a year (September 2025); output down 12% Q1 2024 to Q1 2025 |
| **HEFA sustainable aviation fuel**^[1](https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2021/Jul/IRENA_Reaching_Zero_Biojet_Fuels_2021.pdf)^[2](https://www.dbfz.de/fileadmin/user_upload/Events/Sonstiges/2023/10_IEA_Workshop/07_IEA2023_vanDyk.pdf)^[6](https://www.iata.org/en/pressroom/2025-releases/2025-12-09-04/)^[7](https://www.icao.int/sites/default/files/environmental-protection/CORSIA/Documents/CORSIA%20Eligible%20Fuels/ICAO-document-06-Default-Life-Cycle-Emissions-June-2025.pdf)^[8](https://www.eia.gov/todayinenergy/detail.php?id=65204)^[5](https://www.iea.org/reports/renewables-2025/renewable-transport) | 15-20% jet as standard, up to 50% | USD 1.7 per litre (Rotterdam, September 2020); in 2025 SAF cost about twice fossil jet, and up to five times in mandated markets | ICAO defaults including land-use change: used cooking oil 13.9, tallow 22.5, soybean 61.1-62.9, rapeseed 70.2-71.3, palm 74.0-96.6 g CO2eq/MJ, against 89 for fossil jet | early commercial | 1 Mt in 2024, 1.9 Mt in 2025; US capacity about 30,000 barrels a day (May 2025); IEA forecasts 9 billion litres by 2030 |
| **Co-processing in oil refineries**^[7](https://www.icao.int/sites/default/files/environmental-protection/CORSIA/Documents/CORSIA%20Eligible%20Fuels/ICAO-document-06-Default-Life-Cycle-Emissions-June-2025.pdf)^[2](https://www.dbfz.de/fileadmin/user_upload/Events/Sonstiges/2023/10_IEA_Workshop/07_IEA2023_vanDyk.pdf) | Not quantified | Not quantified | ICAO, biogenic share: used cooking oil 16.7, tallow 27.2, soybean 61.4-63.2 g CO2eq/MJ | early commercial | 13 facilities announced |
| **Gasification with Fischer-Tropsch synthesis**^[2](https://www.dbfz.de/fileadmin/user_upload/Events/Sonstiges/2023/10_IEA_Workshop/07_IEA2023_vanDyk.pdf)^[1](https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2021/Jul/IRENA_Reaching_Zero_Biojet_Fuels_2021.pdf)^[7](https://www.icao.int/sites/default/files/environmental-protection/CORSIA/Documents/CORSIA%20Eligible%20Fuels/ICAO-document-06-Default-Life-Cycle-Emissions-June-2025.pdf)^[10](https://www.wastedive.com/news/fulcrum-bioenergy-sierra-biofuels-reno-nevada-shutdown-eric-pryor/717916/) | 14-18% distillate by mass from residues | USD 4,560-5,560 per kW for early US plants; over USD 1 billion per plant | ICAO: agricultural residues 7.7, forestry residues 8.3, municipal waste 5.2 g CO2eq/MJ | pilot | The only commercial plant (Fulcrum Sierra, from 2022) shut in May 2024; 20 plants (2.24 billion litres a year) announced |
| **Alcohol-to-jet**^[1](https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2021/Jul/IRENA_Reaching_Zero_Biojet_Fuels_2021.pdf)^[7](https://www.icao.int/sites/default/files/environmental-protection/CORSIA/Documents/CORSIA%20Eligible%20Fuels/ICAO-document-06-Default-Life-Cycle-Emissions-June-2025.pdf)^[2](https://www.dbfz.de/fileadmin/user_upload/Events/Sonstiges/2023/10_IEA_Workshop/07_IEA2023_vanDyk.pdf)^[11](https://www.hydrocarbonprocessing.com/news/2025/11/lanzajet-produces-first-jet-fuel-from-ethanol-at-a-commercial-scale/) | Up to 70% jet in theory | Not quantified | ICAO: sugarcane ethanol 32.6-52.9, corn ethanol 72.4-100.6 g CO2eq/MJ | early commercial | First commercial-scale plant (LanzaJet Freedom Pines, US) produced fuel in November 2025; 21 plants (2.84 billion litres a year) announced |

HEFA dominates because it is a simple refinery process, but feedstock limits it: scarce waste oils give about 14 g CO2eq/MJ against 89 for fossil jet, while crop oils with land-use change approach fossil levels. Fischer-Tropsch has the lowest emissions and largest feedstock pool but costs over USD 1 billion per plant and yields only 14-18% fuel by mass. Alcohol-to-jet inherits ethanol's land-use emissions. SAF costs roughly two to five times fossil jet.

#### How each method works
**HEFA renewable diesel (HVO)**

Oils and fats are reacted with hydrogen over a catalyst to remove oxygen, and the paraffins are isomerised into a drop-in replacement for fossil diesel.^[1](https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2021/Jul/IRENA_Reaching_Zero_Biojet_Fuels_2021.pdf)^[3](https://eur-lex.europa.eu/eli/dir/2018/2001/oj)^[4](https://www.eia.gov/biofuels/update/table1.pdf)^[5](https://www.iea.org/reports/renewables-2025/renewable-transport)
**HEFA sustainable aviation fuel**

The same paraffins are cracked and isomerised more severely, distilled to the jet range and blended with fossil jet (approved 2011).^[1](https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2021/Jul/IRENA_Reaching_Zero_Biojet_Fuels_2021.pdf)^[2](https://www.dbfz.de/fileadmin/user_upload/Events/Sonstiges/2023/10_IEA_Workshop/07_IEA2023_vanDyk.pdf)^[6](https://www.iata.org/en/pressroom/2025-releases/2025-12-09-04/)^[7](https://www.icao.int/sites/default/files/environmental-protection/CORSIA/Documents/CORSIA%20Eligible%20Fuels/ICAO-document-06-Default-Life-Cycle-Emissions-June-2025.pdf)^[8](https://www.eia.gov/todayinenergy/detail.php?id=65204)^[5](https://www.iea.org/reports/renewables-2025/renewable-transport)
**Co-processing in oil refineries**

Up to 5% fats or oils are fed into an existing refinery hydrotreater with fossil fractions.^[7](https://www.icao.int/sites/default/files/environmental-protection/CORSIA/Documents/CORSIA%20Eligible%20Fuels/ICAO-document-06-Default-Life-Cycle-Emissions-June-2025.pdf)^[2](https://www.dbfz.de/fileadmin/user_upload/Events/Sonstiges/2023/10_IEA_Workshop/07_IEA2023_vanDyk.pdf)
**Gasification with Fischer-Tropsch synthesis**

Wood, residues or waste are gasified to syngas (carbon monoxide and hydrogen), cleaned, and synthesised over a catalyst into hydrocarbons that are cracked to jet and diesel.^[2](https://www.dbfz.de/fileadmin/user_upload/Events/Sonstiges/2023/10_IEA_Workshop/07_IEA2023_vanDyk.pdf)^[1](https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2021/Jul/IRENA_Reaching_Zero_Biojet_Fuels_2021.pdf)^[7](https://www.icao.int/sites/default/files/environmental-protection/CORSIA/Documents/CORSIA%20Eligible%20Fuels/ICAO-document-06-Default-Life-Cycle-Emissions-June-2025.pdf)^[10](https://www.wastedive.com/news/fulcrum-bioenergy-sierra-biofuels-reno-nevada-shutdown-eric-pryor/717916/)
**Alcohol-to-jet**

Ethanol or isobutanol is dehydrated to light olefins, which are joined into longer chains and hydrogenated to jet fuel.^[1](https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2021/Jul/IRENA_Reaching_Zero_Biojet_Fuels_2021.pdf)^[7](https://www.icao.int/sites/default/files/environmental-protection/CORSIA/Documents/CORSIA%20Eligible%20Fuels/ICAO-document-06-Default-Life-Cycle-Emissions-June-2025.pdf)^[2](https://www.dbfz.de/fileadmin/user_upload/Events/Sonstiges/2023/10_IEA_Workshop/07_IEA2023_vanDyk.pdf)^[11](https://www.hydrocarbonprocessing.com/news/2025/11/lanzajet-produces-first-jet-fuel-from-ethanol-at-a-commercial-scale/)

#### Sources

1. [Reaching Zero with Renewables: Biojet fuels](https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2021/Jul/IRENA_Reaching_Zero_Biojet_Fuels_2021.pdf) IRENA, 2021
2. [Progress in commercialisation of biojet / SAF (van Dyk, IEA Bioenergy workshop presentation)](https://www.dbfz.de/fileadmin/user_upload/Events/Sonstiges/2023/10_IEA_Workshop/07_IEA2023_vanDyk.pdf) IEA Bioenergy Task 39 (hosted by DBFZ), 2023
3. [Directive (EU) 2018/2001 (Renewable Energy Directive II), Annex V: typical and default greenhouse gas savings for biofuels; fossil comparator 94 g CO2eq/MJ. Default values not changed by amending Directive (EU) 2023/2413 (RED III); a Commission revision was in draft in 2026](https://eur-lex.europa.eu/eli/dir/2018/2001/oj) European Union (EUR-Lex), 2018
4. [Monthly Biofuels Capacity and Feedstocks Update, Table 1: U.S. biofuels operable production capacity](https://www.eia.gov/biofuels/update/table1.pdf) US Energy Information Administration, 2025
5. [Renewables 2025: Renewable transport](https://www.iea.org/reports/renewables-2025/renewable-transport) International Energy Agency, 2025
6. [SAF Production Growth Rate is Slowing Down, Essential to Correct Course Ahead of e-SAF Mandates (press release, 9 December 2025)](https://www.iata.org/en/pressroom/2025-releases/2025-12-09-04/) IATA, 2025
7. [CORSIA Default Life Cycle Emissions Values for CORSIA Eligible Fuels (ICAO document 06)](https://www.icao.int/sites/default/files/environmental-protection/CORSIA/Documents/CORSIA%20Eligible%20Fuels/ICAO-document-06-Default-Life-Cycle-Emissions-June-2025.pdf) International Civil Aviation Organization, 2025
8. [U.S. sustainable aviation fuel production takes off as new capacity comes online (Today in Energy, 6 May 2025)](https://www.eia.gov/todayinenergy/detail.php?id=65204) US Energy Information Administration, 2025
9. [Fulcrum BioEnergy shuts down Sierra BioFuels plant in Nevada (5 June 2024)](https://www.wastedive.com/news/fulcrum-bioenergy-sierra-biofuels-reno-nevada-shutdown-eric-pryor/717916/) Waste Dive, 2024
10. [LanzaJet produces first jet fuel from ethanol at a commercial scale (19 November 2025)](https://www.hydrocarbonprocessing.com/news/2025/11/lanzajet-produces-first-jet-fuel-from-ethanol-at-a-commercial-scale/) Hydrocarbon Processing, 2025

## Other sections

- [Summary](https://www.materialinsights.org/energy/hvo_saf/index.md)
- [Energy overview](https://www.materialinsights.org/energy/hvo_saf/energy/index.md)
- [Correlation](https://www.materialinsights.org/energy/hvo_saf/correlation/index.md)
- [Efficiency](https://www.materialinsights.org/energy/hvo_saf/efficiency/index.md)
- [Resources and labour](https://www.materialinsights.org/energy/hvo_saf/resources/index.md)
- [Impact on the biosphere](https://www.materialinsights.org/energy/hvo_saf/biosphere/index.md)
- [Overview](https://www.materialinsights.org/energy/hvo_saf/overview/index.md)
- [Production route](https://www.materialinsights.org/energy/hvo_saf/routes/index.md)
- [Production](https://www.materialinsights.org/energy/hvo_saf/production/index.md)
- [Feedstocks](https://www.materialinsights.org/energy/hvo_saf/feedstocks/index.md)
- [Cycles](https://www.materialinsights.org/energy/hvo_saf/cycles/index.md)
- [Trading](https://www.materialinsights.org/energy/hvo_saf/trading/index.md)
- [Movement](https://www.materialinsights.org/energy/hvo_saf/movement/index.md)
- [Regulation](https://www.materialinsights.org/energy/hvo_saf/regulation/index.md)
- [Characteristics](https://www.materialinsights.org/energy/hvo_saf/characteristics/index.md)
- [Emissions](https://www.materialinsights.org/energy/hvo_saf/emissions/index.md)
- [Relationships](https://www.materialinsights.org/energy/hvo_saf/links/index.md)