Voltage and current (amps) are inversely proportional
12 volts X 2 amps = 24 watts
2 volts x 12 amps = 24 watts
the higher the Ampcapity the larger the wire. The larger the wire the the bigger the conduit needs to be driving up the cost of the infrastructure. It becomes a scale of economy when your building a factory. Not applicable when building a model rail road. Power is what you buy from your utility provider Measured in watts and as you can see from the above math it does not change by simply Increasing voltage. Simply stated 240volt appliances are not cheaper to operate they simply require smaller wire . ��
