Kinetic energy structure of the ejecta of GW170817 for quasi-spherical outflows from Mooley et al. (2017; gray lines) and for the structured jet that we present here (red line). Orange filled dots: kinetic energy of the red, purple, and blue kilonova component associated to GW170817 as derived by Villar et al. (2017). Blue lines: SGRBs. For the SGRB slow ejecta we report a representative limit derived from the analysis of very late-time radio observations from Fong et al. (2016), while the shaded area marks the beaming-corrected E_k of the jet component in SGRBs as derived by Fong et al. (2015) for ϵ_B = 0.1 (note that smaller values of ϵ_B would lead to E_k that would extend to larger values, see e.g., Fong et al. 2015, their Figure 7). This plot highlights the difference between quasi-spherical outflows (which lack an ultra-relativistic component and require a large amount of energy to be coupled to slowly moving ejecta Γ < 2) and structured ultra-relativistic outflows (which have properties consistent with SGRBs and can be energetically less demanding). The peak time of the non-thermal light-curve of GW170817 will constrain the minimum Γβ of the ejecta in quasi-spherical models.