  This paper examines the reduction in brown power consumption of transport
networks and data centres achieved by caching Video-on-Demand (VoD) contents in
solar-powered fog data centers with Energy Storage Devices (ESDs). A Mixed
Integer Linear Programming (MILP) model was utilized to optimize the delivery
from cloud or fog data centres. The results reveal that for brown-powered cloud
and fog data centres with same Power Usage Effectiveness (PUE), a saving by up
to 77% in transport network power consumption can be achieved by delivering VoD
demands from fog data centres. With fully renewable-powered cloud data centres
and partially solar-powered fog data centres, savings of up to 26% can be
achieved when considering 250 m2 solar cells. Additional saving by up to 14%
can be achieved with ESDs of 50 kWh capacity.
