Subsidies, primarily net metering. With panels on your house the grid is still providing you a key service, providing you with any power you need in excess of

Subsidies, primarily net metering. With panels on your house the grid is still providing you a key service, providing you with any power you need in excess of what you produce, and sinking any extra for you. But with net metering you only pay in proportion to your net usage, effectively compensating you at retail rates for the power you supply to the grid.