No affiliation and no idea of price, but I thought it a nice little product for off-gridders.
We are familiar with throttling PV inverters using frequency shifting so production marries consumption.
This little relay is geared up to turn on loads at higher frequencies raising consumption to match production.
It’s called a Catch Power solar relay, in case the link doesn’t work.
EDIT: Actually at AUS $ 357.50, they can keep it.