This study presents current (2020) waste and residue feedstock availability in the European Union and the United Kingdom and provides projections for 2030 and 2050. The study considers the availability of agricultural residues, forestry residues, and biogenic waste. The study deems available only the feedstock that can be collected with no harm on the environment, and thus, takes into consideration the protection of soil quality and agricultural, forestry, and waste management. It also takes into account how much of the feedstock is currently used or combusted for energy, since displacing a feedstock from its current use can lead to indirect increases in greenhouse gas emissions.