Rising energy demand and climate change pressures highlight the urgent need for sustainable strategies in the transport sector, not only to reduce greenhouse gas emissions but also to inform effective environmental management and policy decisions. Renewable biofuels produced from bio-hydrotreated oils have emerged as a promising alternative due to their compatibility with conventional diesel engines, lower pollutant emissions, and potential to support climate mitigation objectives. Using waste vegetable oils (WVO) as feedstock further enhances sustainability by valorizing waste streams, reducing dependence on virgin resources, and aligning with circular economy principles.
Integrating green hydrogen in the production process improves environmental performance by providing a low-carbon hydrogen source for hydrotreatment.
This study presents a comprehensive environmental assessment of renewable biofuel production in Portugal, using WVO feedstock and green hydrogen generated from a combined solar and wind electricity supply.
The assessment encompasses the full production chain, including feedstock preprocessing, electricity supply and electrolyser operation, biofuel synthesis, transportation, and disposal. Environmental impacts are quantified across multiple categories, including global warming potential (GWP), human toxicity, acidification, eutrophication, ozone depletion, and resource depletion.
The results indicate that producing renewable biofuel from WVO and green hydrogen powered by solar and wind energy reduces GWP by approximately
0.45 kg CO₂ per kg biofuel compared to conventional processes, with a value observed at 0.304 kg CO₂/ biofuel. Transportation of feedstocks contributes around 37% of total GWP, mainly due to fossil fuel use in trucks and ships. Feedstock choice and electricity source strongly influence overall environmental outcomes.
These findings demonstrate that combining waste-derived feedstocks with green hydrogen and renewable electricity not only reduces the environmental footprint of renewable biofuel production but also provides actionable insights for environmental understanding, ecosystem restoration strategies, and informed policy-making aimed at promoting sustainable energy and transportation systems.