Eamon Ryan (Dublin Bay South, Green Party) | Oireachtas source

In the short run, in the next decade, as I said, it is likely to be the use of waste oils, waste materials, food and other materials. There are issues around that and, globally, there have been real issues about land-use implications and how we can verify and be certain that waste cooking oil is not coming from a palm oil plantation. Nonetheless, that is likely to be the first step. The second major step towards other technological developments, including those like hydrogen, as mentioned by Deputy O'Rourke, is likely to be into the next decade. However, I believe that is where it will and must go as part of the decarbonisation of aviation, given the scale of fuel that we need could not be made by the likes of waste oil products. That will most likely be an interim technology as we move towards other synthetic, hydrogen-based fuels.