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Algal biomass is a substrate for biogas production via anaerobic digestion, and a feedstock for various liquid biofuels. This chapter covers the EU renewable energy framework as it applies to algal bioenergy, the sustainability criteria that algae must meet to qualify as a renewable fuel, the ABP and waste law interface for digestate from algae, and the emerging carbon farming context.

Directive (EU) 2018/2001 of the European Parliament and of the Council of 11 December 2018 on the promotion of the use of energy from renewable sources (recast) (RED II), OJ L 328, 21.12.2018, p. 82, as amended by Directive (EU) 2023/2413 (RED III).

Note: Search EUR-Lex for CELEX:02018L2001 for the current consolidated version of RED II/III.

Relevance to algae: The Renewable Energy Directive (RED II, as amended by RED III in 2023) establishes the framework for counting and promoting renewable energy in the EU's energy mix. Algae are explicitly mentioned in the Directive as a feedstock for advanced biofuels (Annex IX, Part A). Key provisions:

• Advanced biofuels (Annex IX Part A): algae, seaweeds, and microalgae that do not require arable land to grow are listed as feedstocks eligible for the advanced biofuel category, which receives double-counting credits in EU member state national targets. This is a significant commercial incentive for algae-to-biofuel pathways.
• Sustainability criteria (Art. 29): biofuels, bioliquids and biomass fuels must meet binding sustainability criteria to count towards renewable energy targets. The key criteria relevant to algae:
  1. Greenhouse gas (GHG) saving threshold: fuel must achieve a minimum GHG saving compared to the fossil fuel comparator (currently 65% for fuels from new plants). The GHG saving must be calculated using the methodology in Annex V or VI.
  2. Land use and biodiversity criteria: biomass must not come from areas with high biodiversity value (primary forest, designated protected areas, highly biodiverse grasslands) or high carbon stock (wetlands, peatlands, continuously forested areas). Algae grown on non-arable land, in sea water, or in closed systems generally satisfy these criteria more easily than terrestrial energy crops.
• Biomethane and renewable gases: algae-derived biomethane (biogas upgraded to natural gas quality) can be counted under the RED II framework as a renewable gas; rules on guarantees of origin and sustainability certification apply.

The GHG saving calculation methodology specified in Annex V and VI of RED II is detailed and requires either:

• Use of the published default values for specific feedstocks and pathways (where available — algae-specific default values are limited); or
• A disaggregated (actual value) calculation following the methodology defined in the Annex, accounting for actual cultivation energy use, processing energy, transport, and co-product allocation.

The BioGrace calculation tool (developed under a European project and freely available) provides a spreadsheet-based methodology for calculating GHG savings in compliance with RED II requirements. It is widely used by biofuel producers and their certification bodies.

The GHG savings from algae-derived biofuels can be high in principle (algae require no agricultural land and can capture CO₂) but the calculation depends critically on the energy input to cultivation (lighting for closed systems, aeration, pumping). High energy consumption in cultivation can significantly reduce the net GHG saving calculation, and in some cultivation scenarios may fail the sustainability threshold. Producers developing algae-to-bioenergy pathways should model their specific system's GHG footprint before assuming eligibility.

Biofuel sustainability criteria must be demonstrated through certification by a recognised voluntary scheme (or national certification systems meeting equivalent criteria). The Commission recognises several voluntary schemes under the RED II framework, including:

• ISCC (International Sustainability and Carbon Certification)
• Bonsucro
• RTRS
• Others listed in the Commission database

For algae-derived biofuels and biomethane, ISCC is currently the most widely applicable scheme, as it covers a broad range of feedstocks including algae. Producers seeking to sell algae-derived fuel into the EU renewable energy market must obtain certification from a recognised scheme before making sustainability claims.

Anaerobic digestion (AD) of algal biomass produces biogas (a mixture of methane and CO₂, with minor contaminants) and a liquid/solid digestate. Both products have regulatory implications:

Raw biogas can be used for on-site heat and electricity generation; upgraded to biomethane, it can be injected into the gas grid (subject to grid injection rules, which vary by member state) or used as vehicle fuel. In all cases, counting towards renewable energy targets requires sustainability certification as described above.

Digestate is the post-digestion residue from AD. Its regulatory status depends on the nature of the input material:

• Digestate from algae grown on non-ABP substrates (e.g. from clean cultivation water, without animal-origin materials) may be eligible for use as a fertilising product under the FPR CMC framework or under national fertiliser law, subject to contaminant testing (Annex I to the FPR).
• Digestate from algae grown on ABP-containing substrates (manure, fish waste) is governed by the ABP Regulation and must be processed and used in accordance with the applicable ABP rules (see Animal By-products).
• The waste law status of digestate (whether it has exited waste status) is also relevant; see Waste, Wastewater, Nutrient Recovery and End-of-Waste.

Directive 2009/31/EC of the European Parliament and of the Council of 23 April 2009 on the geological storage of carbon dioxide, OJ L 140, 5.6.2009, p. 114. EUR-Lex

Relevance to algae: Algae are studied as a biological carbon capture mechanism, particularly in the context of CO₂ utilisation in algae cultivation. CO₂ from industrial flue gases is increasingly used as a nutrient input for photosynthetic microalgae, and the resulting biomass sequesters carbon in organic form. This is not “geological storage” for the purposes of the CCS Directive (which governs capture and geological injection of CO₂), but it is increasingly relevant in the context of the EU Carbon Removal Certification Framework (see Greenhouse Gases and Climate).

• Advanced biofuel designation (Annex IX Part A) is a significant commercial advantage — if algae biomass qualifies, biofuel derived from it is double-counted in member state targets, creating market demand; confirm your feedstock qualifies before investing in this market.
• Model the GHG saving for your specific production system before committing to the biofuel market; high cultivation energy consumption can reduce or eliminate the GHG saving claim.
• Obtain certification under a recognised voluntary scheme (ISCC recommended) before selling biofuel or biomethane on the EU renewable energy market.
• Digestate quality from algae AD systems must be tested and its regulatory status under the FPR and/or ABP rules determined before it can be sold or used as a fertilising product.
• Grid injection of biomethane requires national regulatory approval (grid injection licence) in addition to sustainability certification; rules vary significantly between member states.

See also: Greenhouse Gases and Climate | Waste, Wastewater, Nutrient Recovery | Animal By-products | Fertiliser Product Regulation

Last reviewed: June 2026.