Portugal has legalized the use of digestate as fertilizer — what are the benefits?
Thus, the country has officially classified digestate — a nutrient-rich coproduct of anaerobic digestion (AD) — as a ‘by-product’ instead of ‘residue’.
For the SAF platform, we have prepared a translation of a review by the WBA (World Biogas Association) on the prospects of such solution not only for the bioenergy sector, but also for the country as a whole.
From a legal standpoint, this means that digestate can now be legally used as fertiliser in Portugal without being subject to waste management constraints, streamlining its application in agriculture and closing a key loop in the biogas value chain.
Why is this important?
AD transforms organic waste — such as manure, food waste and wastewater sludge — into biogas and digestate. While biogas has multiple applications — including electricity and heat generation, use as a vehicle fuel, injection into the gas grid, or as a feedstock for producing refined green fuels — digestate also plays a vital role. It contains essential nutrients such as nitrogen, phosphorus and potassium, making it a powerful biofertiliser.
However, in much of the EU, digestate is still legally classified as a ‘residue’, which means it must undergo additional (often costly and bureaucratic) permitting to be applied to land. This classification undermines its value and contributes to project delays — for instance in countries like Spain, where permitting challenges are already significant.
Advantages
Portugal’s decision helps unlock the full circular potential of biogas, offering a multiple benefits:
- Environmental: Reduced reliance on synthetic fertilisers, lower emissions from waste management, and improved soil health.
- Economic: Lower operating costs for biogas producers — since as a residue digestate would require compliance with specific regulations for transport, storage and application, including pasteurisation — and stronger incentives for agricultural stakeholders to adopt AD solutions.
- Social: Farming industry further development with the support of constant and reliable fertiliser production.
Read the full material with a chapter on the situation in Spain and prospects for the EU and the world on the SAF platform.
We remind you that UABIO is a partner of the Sustainable agribusiness platform (SAF).
SAF is a communication platform that brings together agribusiness stakeholders and aims to establish strong links between market players and introduce sustainable approaches in agriculture. For this platform, our team prepares verified professional content on the bioenergy sector.
