How to Achieve Reliability in Home Battery Systems
Energy Storage - Redundancy built into your redundant power supply with microinverters
Reliability is the most important quality in an energy storage system. For the purposes of this article, we will focus on the inverter’s role in reliability for energy storage.
Fundamentals of a battery based storage system Brief:
A battery’s power output, similar to solar production, is Direct Current (DC). In order to use the power from a battery in a home it needs to be inverted to Alternating Current (AC). All of the power flowing from and to a battery (as in AC coupled systems) must pass through an inverter. Understanding this, the inverter is the vehicle by which we have access to the battery's energy.
Scott Adams, the author of Dilbert, wrote a thought experiment where he asks the question, what is more important: the package or the delivery man? Which brought which to a specific location? If not for the address on the package and the package itself, the delivery man would never arrive but the package would never have gone anywhere without the delivery man. The two are equally important to whoever is receiving the package. This is also true in an energy storage system in regard to the battery and inverter. The inverter is the delivery system by which we receive the energy in the battery.
The Delivery Man: Inverters
In another blog we discussed the different inverter technologies, demarcating string (or central) inverters and microinverters. In summary of that discussion, a string, or central, inverter is a system that relies on a single unit that all power is funneled through whereas in a microinverter system the power is dispersed, each microinverter is responsible for only a fraction of the total output. The biggest difference in functionality of these two systems is redundant power supply. If a central inverter fails there is no package delivery, if a microinverter fails, only a fraction of the package is lost. Microinverter systems offer a redundant design and are therefore more reliable than centralized inverter systems.
It seems like common sense that we would want to disburse the potential for failure in our energy storage systems to avoid complete blackout. The very idea of having backup power is the understanding that we should have a redundant approach to our energy system. When selecting an energy storage system, the method of delivering that stored energy is just as important as the energy itself. Redundancies in design result in reliability in application.
In fact, FEMA recommends microinverters for these exact reasons. In disaster situations, reliability is key.
