Final answer:
The primary difference between a stand-alone and a grid-connected PV system is their connection to the electrical grid. Stand-alone systems operate independently and use storage, while grid-connected systems are connected to the utility grid and can export excess energy.
Step-by-step explanation:
The primary difference between a stand-alone and a grid-connected PV system lies in their operation and connection to the electrical grid.
A stand-alone PV system, also known as an off-grid system, is not connected to the electrical grid. It operates independently and typically includes storage, such as batteries, to store excess energy produced during the day for use at night or when there is no sunlight. stand-alone systems are commonly used in remote locations or areas where grid connection is not available.
On the other hand, a grid-connected PV system is connected to the local electrical utility grid. This allows for the export of excess solar energy to the grid during the day and the use of utility electricity at night or when solar production is insufficient. Most PV installations in the US are grid-tied due to the convenience of grid availability and the lower cost compared to adding storage to the system.