On-grid means your solar system is tied to your local utility’s GRID. … Being grid-tied is beneficial because you don’t have to buy an expensive battery back-up system to store any excess energy.
A grid-tied solar panel system is simply a solar energy system that is connected to the electrical grid and, therefore, uses electricity from both the solar panel system and the electrical grid. Because of this, a grid-tied solar system doesn’t have to meet all of the electricity demands of the home.
Solar water heating (SWH) is the conversion of sunlight into heat for water heating using a solar thermal collector
Rooftop solar panels soak up the sun. When the sunlight hits the solar cells on a rooftop solar panel, it converts particles of sunlight (photons) into electrons of direct current (DC) electricity.