The energy distributions of four 2+1 dimensional black hole solutions were obtained by using the Einstein and M{\o}ller energy-momentum complexes. while r→∞, the energy distributions of these four solutions become divergence.
@article{arxiv.gr-qc/0309130,
title = {The Energy for 2+1 Dimensional Black Hole Solutions},
author = {I-Ching Yang and Irina Radinschi},
journal= {arXiv preprint arXiv:gr-qc/0309130},
year = {2008}
}