With moderate fluctuations taken into account, the variable plans is still cheaper. Our bill is approximately $10 more in the winter, but we’d still save $138 over the course of a year. It’s more a question of whether you can roll with the punches of an unpredictable rate, or would sleep easier knowing your bill is going to look the same month after month.
The mid to late 1880s saw the introduction of alternating current (AC) systems in Europe and the U.S. AC power had an advantage in that transformers, installed at power stations, could be used to raise the voltage from the generators, and transformers at local substations could reduce voltage to supply loads. Increasing the voltage reduced the current in the transmission and distribution lines and hence the size of conductors and distribution losses. This made it more economical to distribute power over long distances. Generators (such as hydroelectric sites) could be located far from the loads. AC and DC competed for a while, during a period called the War of Currents. The DC system was able to claim slightly greater safety, but this difference was not great enough to overwhelm the enormous technical and economic advantages of alternating current which eventually won out.