What is DC-coupled and AC-coupled PV & energy storage?

This document examines DC-Coupled and AC-Coupled PV and energy storage solutions and provides best practices for their deployment. In a PV system with AC-Coupled storage, the PV array and the battery storage system each have their own inverter, with the two tied together on the AC side.

How does co-locating a solar inverter reduce the cost of deploying solar?

Coupling by co-locating storage and solar can decrease the overall net costs of deploying PV and storage (AC coupling). Further cost reductions are possible via sharing the inverter (DC coupling). This can reduce clipping but can result in non-optimal storage dispatch, especially if the storage capacity is sized close to the size of the inverter.

What is AC-coupled PV & energy solutions?

AC-Coupled PV and energy solutions are employed as PV retrofits or where the storage component differs from the PV component widely in power rating. The main advantage of the DC-Coupled energy storage solution is the ability to PV clip recapture with a higher DC/AC ratio.

What are the advantages of a DC-coupled energy storage solution?

The main advantage of the DC-Coupled energy storage solution is the ability to PV clip recapture with a higher DC/AC ratio. Another major benefit is the smaller size of the inverter per PV Watt.

What is a PV system with AC-coupled storage?

In a PV system with AC-Coupled storage, the PV array and the battery storage system each have their own inverter, with the two systems tied together on the AC side. The two systems are thus electrically separated, allowing a customer to size each separately.

What is a DC-coupled Solar System?

DC-Coupled system ties the PV array and battery storage system together on the DC-side of the inverter, requiring all assets to be appropriately and similarly sized in order for optimized energy storage and power flow. Mid to large-scale solar is a non-reversible trend in the energy mix of the U.S. and world.