Not quite true, inverters stop drawing power from solar panels when there is no demand for it, solar users see this when their batteries become full and the solar output drops to meet household demand, assuming their is excess solar. If the grid is taking power from solar panels, then it means someone on the grid needs the electricity. The issue for eskom is would it be a cheaper cost to pay you for the solar power or for them to use the power plant to meet demand.
Solar inverters on rooftop PV systems could soon be controlled and switched off remotely following a crackdown from clean energy authorities. The Clean
www.energymatters.com.au
South australia looking to remotely shutdown inverters to prevent grid instability from over supply AND paying consumers producing solar.