Electricity cost of mining
Basic Algebra 101:

100 W = 0.1 kW


so

0.1 (kW) * 0.1399 (USD/kWh) = ~$0.014 (USD/hour)


or

0.1 (kW) * 24 (h/Day) = 2.4 kWh/Day

2.4 (kWh/Day) * 0.1399 (USD/kWh) = $0.3358 (USD/Day)