3. By way of derogation from paragraph 2, where no technical assessments of available alternatives to existing feedstock uses and of emission levels of existing feedstock uses carried out under the Protocol are available that provide a sufficient basis for taking a decision whether to prohibit a feedstock use, the Commission shall, by 31 December 2027, make its own assessment on the basis of scientific recommendations on the existing feedstock uses, the impacts in terms of ozone-depleting potential (ODP) and the availability of more precise data on the greenhouse gas emissions from feedstock, technological developments resulting in the availability of technically feasible alternatives, and the energy use, efficiency, economic feasibility and cost of those alternatives, and shall adopt, where appropriate, on the basis of that assessment, the delegated acts referred to in paragraph 2.