This talk will discuss global and quasilocal properties of energy in spacetimes with negative cosmological constant using spinor methods. In the first half of the talk, a general positive energy theorem is developed for asymptotically, locally AdS spacetimes with boundary geometry admitting compact cross-sections with parallel or Killing spinors. Various examples will be used to illustrate the effect of the boundary geometry. In the second half of the talk, a new notion of quasilocal mass will be defined for generic, compact, 2D, spacelike surfaces in 4D spacetimes with negative cosmological constant. The new quasilocal mass is based on work for vanishing cosmological constant by Penrose and Dougan & Mason and will be shown to have a number of physically desirable properties.
