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A techno-economic assessment of a novel biorefinery concept is carried out. It combines the hydrotreatment of vegetable oils (HEFA) with a power-to-gas (PTG) unit that provides the required hydrogen. Several scenarios are examined: the electricity supply for the PTG unit is varied from a grid-based supply to a renewable island solution; the hydrogen supply is varied from a PTG unit to conventional steam reforming; the utilised vegetable oil is varied from jatropha to rapeseed, palm and used cooking oil; the main product is varied from jet fuel to diesel. The HEFA-plant is assumed to process 500 kt of vegetable oil annually. In the reference scenario, jatropha oil is used as feedstock producing 227 kt a−1 of jet fuel. Per ton of processed oil, 1910 kWhel are used to produce 35.7 kg of hydrogen required for its treatment. By using different vegetable oils, both hydrogen demand and fuel output vary in a range of about ±10%. The overall energetic efficiency towards jet fuel is 41.6%. With a bandwidth between 1295 and 1800 EUR t−1 of jet fuel, the specific production costs are three to four times higher than the market price for fossil jet fuel. Operating the refinery in diesel-mode could lower the production costs by ca. 30%. More high-value, long-chained fuels are produced this way due to a lower cracking rate compared to the jet-mode. Investments of around 132 million EUR are required for the HEFA-plant in all scenarios. Investments for the PTG-plant lie around 82 million EUR if there is a constant electricity supply from the grid. They reach 246 million EUR if electricity is supplied in an island-solution based on fluctuating renewables demanding much higher hydrogen production and storage capacities. Total investments in the biorefinery reach 378 million EUR in this case. Despite high capital costs, the largest cost item is vegetable oil – similarly to a conventional HEFA plant. Supporting policy instruments such as subsidies or quotas for renewable jet fuel seem indispensable for an introduction of the PTG-HEFA technology in the short to medium term.

A sustainable way to produce plastics made from biomass (biomass to gas) and electricity (power to gas) could be obtained by the direct synthesis of light alkenes. Samples (≤ 1 g) of the bulk catalysts Co/Fe, Fe/Na/S and the supported catalysts Fe/Mn | MgO and Co | SiO2 are mentioned in the literature to allow the direct synthesis of light alkenes. These materials are studied in extended fixed beds with catalyst amounts between 35 and 70 g and classic syngas (H2 and CO) in this work in order to prepare a potential scale-up of this technology. The influence of activation conditions (H2 or CO as reduction agent; 350 or 420 °C at 1.5 bar) and synthesis temperature (230–500 °C) on catalyst activity and product selectivity are pointed out. Selectivities to ethene of up to 11% are found for Fe/Mn | MgO at T ≈ 440 °C and for Fe/Na/S at T ≈ 310 °C. The other materials did not produce significant amounts of ethene. CO2 and CH4 were the main products in any case, while C2H6 was the main C2 product. Applying CO as reduction agent was superior to activation with H2 at low times on stream (