The invention concerns an ultra-clear glass sheet, i.e. a sheet of glass with high energy transmission, that can be used, in particular, in the solar and architectural fields. More specifically, the invention concerns a sheet of glass having a composition which comprises, in an amount expressed as percentages of the total weight of the glass: SiO2 60-78%; Al2O3 0-10%; B2O3 0-5%; CaO 0-15%; MgO 0-10%; Na2O 5-20%; K2O 0-10%; BaO 0-5%; total iron (expressed in the form of Fe2O3) 0.002-0.03%, the composition comprises a copper content of 0.001 to 0.15% by weight relative to the total weight of the glass, the copper content being expressed in the form of Cu as a percentage by weight relative to the total weight of the glass.