The present invention provides a method of upgrading mixed waste plastic pyrolysis oil comprising the steps of providing a pyrolysis oil stream derived from mixed waste plastic, subjecting the pyrolysis oil stream to fractional condensation to obtain three pyrolysis oil fractions, determining properties of the pyrolysis oil fractions, determining an adjusted proportion of the pyrolysis oil fractions to be fed to a hydro-upgrading section for obtaining a product with a predetermined product specification, feeding the pyrolysis oil fractions in the adjusted proportion to a pyrolysis oil hydro-upgrading section to perform a hydro-upgrading operation, adjusting one or more control parameters of the pyrolysis oil hydro-upgrading section according to the adjusted proportion of the pyrolysis oil fractions and the predetermined product specification; and separating an hydro-upgrading section outlet stream to obtain a product stream with the predetermined product specification. In this way, the upgrading of the pyrolysis oil can be tailored and adapted to the great variability of properties of pyrolysis oil derived from mixed plastic waste pyrolysis in order to obtain a uniform commercial-grade fuel that can achieve a premium market value. The process may comprise in-situ hydrogen generation by water electrolysis powered by solar photovoltaic energy.