I love this brain teaser. If you want to make it even more weird, consider that the second plant is communicating it's phase back to the first one! Paradox! Bu

I love this brain teaser. If you want to make it even more weird, consider that the second plant is communicating it's phase back to the first one! Paradox! But the answer is contained in the parent comment. Each plant generates more power if the phase lags and produces less if the phase leads. Basically, electricity consumers drag on the phase and the plants use this to control output power, so that the phase matching can be done purely locally. But it is a lot simpler if you use high voltage DC! If you do that you can connect networks with entirely different phases!