Mass. Gen. Laws ch. 164 § 47B
Any municipality acting by and through its municipal light board may construct, purchase, operate, own, lease, rent, maintain, dispose of, share costs of, or otherwise have the right to the use, or portions thereof, of subtransmission, transmission, distribution, and generation facilities and equipment located outside of the municipality's limits. All such subtransmission, transmission, distribution, and generation facilities and equipment, or portions thereof, referred to in this section so constructed, purchased, owned, leased, rented, operated, maintained, or otherwise having the right to be used by any municipality shall hereafter be considered "plant" under the provisions of sections 34, 40, and 57 of this chapter. Any municipality acting by and through its municipal light board is hereby authorized to pay for the construction, purchase, lease, rent, or the right to use, or portions thereof, of the subtransmission, transmission, distribution, and generation facilities and equipment referred to in this section from those amounts accumulated for depreciation.
Mass. Gen. Laws ch. 164, § 47B