  Ensuring seamless coverage accounts for the lion's share of the energy
consumed in a mobile network. Overlapping coverage of three to five mobile
network operators (MNOs) results in enormous amount of energy waste which is
avoidable. The traffic demands of the mobile networks vary significantly
throughout the day. As the offered load for all networks are not same at a
given time and the differences in energy consumption at different loads are
significant, multi-MNO capacity/coverage sharing can dramatically reduce energy
consumption of mobile networks and provide the MNOs a cost effective means to
cope with the exponential growth of traffic. In this paper, we propose an
energy saving market for a multi-MNO network scenario. As the competing MNOs
are not comfortable with information sharing, we propose a double auction
clearinghouse market mechanism where MNOs sell and buy capacity in order to
minimize energy consumption. In our setting, each MNO proposes its bids and
asks simultaneously for buying and selling multi-unit capacities respectively
to an independent auctioneer, i.e., clearinghouse and ends up either as a buyer
or as a seller in each round. We show that the mechanism allows the MNOs to
save significant percentage of energy cost throughout a wide range of network
load. Different than other energy saving features such as cell sleep or antenna
muting which can not be enabled at heavy traffic load, dynamic capacity sharing
allows MNOs to handle traffic bursts with energy saving opportunity.
