Each of these two strings has 35 lights, rated by the supplier as 3.3 watts. So in total less than 7 watts. At 27c per kwh power from the grid, 0.2 cents per hour. And the LED lights should last forever. They cost around $70. The hooks in the ceiling $5. The bamboo pole from own bamboo, on property recently sold.
It's worth looking for ways to do things which are both beautiful and sustainable.