Recently, people use micro-inverters to convert to AC mains at the panels, and current sensing to detect when their panels are producing more power than the hou

Recently, people use micro-inverters to convert to AC mains at the panels, and current sensing to detect when their panels are producing more power than the house is consuming - if so, they turn on (1..n) resistive heating elements in their hot water tank to fully utilise the excess. Another thing to ponder is a sand ‘battery’ as a power / heat sink - lower heat capacity than water but doesn’t boil at 100C so can absorb more energy.