Co-Processing SAF: Standards, Incentives and Regulation

by Maria J. L. Perez and Milica Folić (Topsoe/Biomass Magazine) ... One method of SAF production, known as co-processing, has emerged as a viable solution in the here and now. But what are the regulations and standards that producers need to be aware of?

Co-processing is gaining popularity as a production method to meet the growing demand for SAF in a shorter timeframe as it enables existing refineries to efficiently adopt renewable feedstocks for SAF production using existing infrastructure. All that is needed is for refineries to replace some of the fossil feedstock in their existing kerosene hydrotreater with up to 5% renewable feedstock and to adjust the catalyst loading.

The catalyst adjustment is because adding even a small amount of renewable feedstock can raise the freezing point because of the biogenic n-paraffins produced when the oxygen is removed. To meet the freezing point standards of Jet A and Jet A1 fuels, it is essential to remove these biogenic n-paraffins thoroughly. ...

By utilizing existing refining, transport, and storage facilities, co-processing offers economic competitiveness and rapid availability of SAF. Additionally, the advantage of co-processing lies in its cost-effectiveness, as it eliminates the need for constructing new specialized processing units, resulting in both capital and operational expenditure savings.

Navigating the landscape surrounding co-processing SAF can be complex, however. Here's a breakdown of the key information when it comes to standards, incentives and regulation.

The ASTM standards for co-processing

For aviation fuel, ASTM serves as the international standard for jet fuel quality, and plays a crucial role in ensuring safety, quality and dependability of SAF. Co-processing of SAF is permitted under the ASTM D1655 standard, which provides guidelines for the production of aviation fuels. The standard outlines three types of co-processing:

1. 5 vol% co-processing of mono-, di-, and triglycerides, free fatty acids, and fatty acid esters.
2. 5 vol% co-processing of hydrocarbons derived from synthesis gas via the Fischer-Tropsch process using iron or cobalt catalyst.
3. Co-processing (including co-fractionation) of hydrocarbons derived from hydroprocessed mono-, di-, and triglycerides, free fatty acids, and fatty acid esters (up to 24 vol% of the feed and 10 vol% of the product).

These provisions ensure that SAF production via co-processing adheres to established standards, promoting sustainability and reducing greenhouse gas emissions.

Incentivization of co-processing

Fuel producers can receive credits for producing SAF via co-processing in both the European Union (EU) and the United States (US). In the EU, the ReFuelEU aviation initiative allows any type of SAF to meet SAF mandates, as long as the feedstock and greenhouse gas (GHG) saving criteria are met. In the US, fuel producers can obtain Renewable Identification Number (RIN) and Low Carbon Fuel Standard (LCFS) credits, such as those from California, for SAF produced via co-processing.

It's important to note that there are some limitations and variations in eligibility for credits. SAF produced via co-processing of fatty-acid-based feedstocks is not eligible for the Inflation Reduction Act (IRA) Clean Fuel Production Tax Credit (45Z) in the US. However, SAF produced via co-processing of Fischer-Tropsch wax does qualify for 45Z credits.

Feedstocks and regulation

The selection of feedstocks for co-processing also varies by jurisdiction. In the EU, according to ReFuelEU aviation, three types of biogenic feedstocks are permitted: waste from Annex IX part A, waste from Annex IX part B, and other biogenic feedstocks not listed in Annex IX, provided they are not food and feed crops, intermediate crops, palm fatty acid distillate, or palm and soy-derived materials or soap stock and its derivatives (this exclusion does not apply to any feedstock added to Annex IX). These feedstocks must achieve a minimum of 65% greenhouse gas (GHG) emission savings.

In the US, the choice of feedstocks depends on the specific credits sought, such as RIN in the Renewable Fuel Standard (RFS) scheme, LCFS in California, or Clean Fuel Production Tax Credit (PTC) credits. Each scheme has its own requirements and should be examined individually.

CORSIA and co-processing compliance

Under the Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA), co-processing is allowed for SAF production. The International Civil Aviation Organization (ICAO) considers SAF produced via co-processing as compliant with CORSIA regulations. Guidelines provided by ICAO ensure that SAF produced through co-processing meets the sustainability criteria set forth by CORSIA. The co-processing life cycle assessment (LCA) methodology is described in ICAO document 07, and default LCA values are provided in ICAO document 06.

As more long-term SAF technology pathways mature and scale and investment ramps up, co-processing of SAF offers a promising pathway towards a more sustainable aviation industry. Understanding the regulations and eligibility criteria is crucial for fuel producers looking to contribute to the decarbonization of the aviation industry. By working with established standards and guidelines, co-processing can play a strong initial role in SAF production volumes. READ MORE