Let’s talk about grid-connected storage

Published on June 14, 2016

With the Sol Distribution grid-connected workshop coming up, we’ve put together some questions to ignite the conversation around grid-connected storage.

Question 1: What kind of accessories are usually required for an energy storage system?
Answer: For a solution with the SMA Sunny Storage, the only mandatory accessory is the Energy Meter. A Home Manager can also be used if the user wishes to integrate weather forecasting in their charging algorithms and time windowed charging.

Question 2: What kind of phase connections are compatible with the Sunny Boy Storage inverter?
Answer: The Sunny Boy Storage inverter is a single phase device but typically distribution networks would allow up to 5kW of phase imbalance as long as power factor is one. The inverter can be connected to just one out of the three phases.

Question 3: What are the differences between having HV and LV batteries?
Answer: If we assume the power output of both batteries are the same, then having HV would lower the current. Which would greatly reduce the wiring losses.

Question 4: Are there any installation standards for Li-ion batteries in Australia?
Answer: As of current standards, there is no uniformly agreed guidelines specifically for Li-ion batteries. However, work is underway with documents like this CEC and this ESC that can provide recommendations.

Question 5: What about customers with existing PV systems?
Answer: The SMA Sunny Boy Storage for example, could be used in conjunction with any other inverter for retrofitting a Tesla Powerwall Battery.

Question 6: What about the safety concerns of Li-ion batteries?
Answer: It is true that poorly managed Li-ion batteries can lead to explosions due to overcharging or corrosion due to undercharging, but current battery management units are well programmed to prevent these things from happening. The Tesla Powerwall Battery is also an outdoor unit that further diminishes this hazard should it happen at all.

Other questions that can be explored at the workshop are: what are the difficulties connecting a system to the utility? Or, what are the current rebates for storage in Australia?