Energy conservation. You're pushing (literally) against the electrical workload of the connected circuits (places where people have plugged a device into a sock

Energy conservation. You're pushing (literally) against the electrical workload of the connected circuits (places where people have plugged a device into a socket and made a loop). When there's more to push against, your steam goes less far and your turbine starts to slow. You can then apply more energy and push the system back up to speed.