Does moving from 16GB to 32GB RAM significantly increase power consumption?

Not much — maybe a few watts at most. Each DDR4 stick draws about 2-3 watts at idle and 5-7 watts under load; DDR5 is similar. Going from one stick to two adds roughly 3-5 watts total, like a small LED bulb. Compared to your CPU (65-150W) and GPU (150-400W), RAM power is a rounding error and won’t affect your electricity bill.