Grid-Connected System Overview
A grid-connected renewable energy system offers all the economic advantages of a traditional grid-tied system like net metering and combines them with the energy independence and self-sufficiency of an off-grid system. The grid can be used as much or as little as desired based on energy consumption needs and utility rates because the systems batteries are always available to power loads if the grid goes down or if peak rate charges are too high.
A Typical OutBack Power Grid-Connected System
Inverter / Chargers
Just like with an off-grid system, appliances and other electrical loads in a home operate on AC current. Solar and other renewable sources generate DC current. An inverter is required to convert DC current from the renewable source to usable AC current for home powering needs. Unlike a grid-tied or grid-direct system, however, a grid-connected system incorporates batteries, which may need to be charged from an AC source like the power grid or an AC generator. Essentially, a grid-connected inverter/charger will convert power from DC to AC for consumption and AC to DC for charging. OutBack’s UL 1741 SA listed Radian Series and FXR series Grid-connected inverter/chargers are fully programmable with seven operating modes designed to support a number of energy scenarios.
Charge Controllers
It might seem redundant to have an inverter/charger and a charge controller, but each serves its own purpose in an off-grid system. The charger in an inverter/charger is an AC charger for an AC source such as a generator. A charge controller allows power from a DC source like a solar array to charge the batteries. OutBack’s family of FLEXmax charge controllers have become the industry standard for efficiency and reliability in off-grid and grid-connected applications.
Batteries
By definition, a grid-connected system includes batteries as an additional energy source. Batteries function as the “bank” where excess renewable or inexpensive grid power is deposited and then later withdrawn when needed. Required battery capacity, measured in kWh (kilowatt-hours), depends on the size of the loads that will be powered, or the critical loads that will be backed up in the event of a grid outage, meaning there is no “one size fits all” option. Other battery considerations include battery chemistry, battery size, storage and recyclability of battery materials. OutBack offers a full line of EnergyCell renewable energy batteries and racks to meet virtually any energy storage application.
Other Considerations
UL 1741 SA
UL 1741 SA is the new safety test standard certifying products which meet the rigorous requirements needed to ensure safe and reliable operation in support of grid modernization efforts. Grid support or "smart inverter" functionality will be required by Hawaii and California beginning September 8, 2017. Although Hawaii and California are the first states to require grid support functions, expected updates to the IEEE 1547 interconnection standard will make these functions mandatory throughout most of North America within two to three years. Learn more about UL 1741 SA on our Grid Support page.