Abstract: We discuss the generalization of gravitational energy-momentum pseudo-tensor to Extended Theories of Gravity, in particular to higher-order theories in curvature invariants. This result is achieved by imposing that the local variation of gravitational action of any order n vanishes under rigid translations. We also prove that this tensor, in general, is not covariant but only affine, that is, it is a pseudo-tensor. The pseudo-tensor is calculated in the weak-field limit up to a first non-vanishing term of order h^2, where h is the metric perturbation. The average value of the pseudo-tensor, over a suitable spacetime domain, is obtained. Finally, we calculate the emitted power, per unit solid angle, carried by a gravitational wave in a direction x for a fixed wave number k under a suitable gauge.
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