Height dependence of the different terms in the energy transport at a wavenumber of k = 7 Mm⁻¹, corresponding to a wavelength of approximately 900 km, in the upper panel and k = 20 Mm⁻¹, corresponding to a wavelength of approximately 312 km, in the lower panel. The solid black line shows the contribution from radiation, the solid (dashed) red line the vertical (horizontal) transport of the internal energy, and the solid (dashed) green curve the work done by the vertical (horizontal) pressure gradients.