If you’re considering investing in solar renewable energy for your home or you already have solar panels powering your house, it’s crucial to consider adding battery storage to your proposed or existing system. Adding battery storage to work in conjunction with a conventional grid-tied solar system has the advantages of decreasing, and sometimes eliminating, the costly limitations of a non-battery-based system.
These limitations essentially boil down to two main causes:
1. Generally, a grid-tied system without battery storage cannot produce energy if the utility-grid is offline.
2. Energy can only be supplied to the house when the system is producing power.
If the grid is offline and your system cannot produce power, this can have some serious safety implications. Furthermore, there are many costs associated with losing power (i.e. home businesses, cost of health, loss of vital electronics, etc.).
Most grid-tied microinverters and string inverters on the market, like that from Enphase and SolarEdge, are designed to work only when the grid is online. As soon as the grid shuts down, the inverter will sense this event and immediately shut down, leaving the homeowner powerless if no gas generators or batteries are present.
If power can only be supplied to the house when your system is producing power, then the house-energy offset and the ability to sell back to the grid is limited to only during the daytime (if the weather permits). Consequently, utility companies nationwide are adopting policies and rates that are designed to circumnavigate the energy offset from conventional solar energy systems.
For example, “Time of Use” (TOU), “Peak Demand” charges, and decreased energy sell-back rates are the most popular. These utility rates can greatly decrease the value and Return on Investment (ROI) of a solar energy system. All of these potential issues beg the question, how will energy storage solve these problems?
Battery Storage and Energy Management Benefits
A majority of the limitations associated with having a conventional grid-tied system can be mitigated, or even eliminated, by adding battery storage to your system. Conventional solar systems generally don’t have any meaningful mechanisms of energy management for the end-user.
If the system produces power, then the power will go to the house loads if needed, and if not needed, the power will always go back to the grid. If the grid shuts down, your system shuts down. Other than that, energy management is virtually nonexistent.
With solar plus storage, the potentials for energy management open up many doors when it comes to fully utilizing the capabilities of your solar pv system. There are many different ways to incorporate solar batteries into your system, but all systems with battery storage will essentially use solar and/or the grid to charge the batteries for energy use at a later time. This sole advantage of storing excess solar for later use can translate into many other added benefits.
Power During Power-Outage Emergencies
Having a surplus of energy stored away for emergency situations is arguably a necessity for all households, especially for those who already own a solar system.
If you’re one of the many individuals under utility companies like Pacific Gas and Electric (PG&E) or Southern California Edison (SCE) who experience regular power-outages, you’ll know that such outages can greatly affect your way of life.
Having battery storage with saved energy for a rainy day can make a huge impact on the utility of your system for a variety of reasons, ranging from being able to maintain small day-to-day tasks all the way to ensure the likelihood of an individual’s own safety. Just for these reasons alone, adding batteries to a system can have tremendous payback in the future.
Decrease Your Electricity Bills Despite Changing Utility Rates
Cumbersome utility rates like Time of Use rates (TOU) and Peak-Demand rates can put a heavy damper on the added value and ROI of installing a solar system. By adding battery storage, you can increase the value and ROI of your system by thousands of dollars, if you’re in a jurisdiction where utility rates are rendering your system useless.
TOU charges separate electricity rates by the time of day and increases during the times your energy usage is most likely to be at its highest, also known as, “Peak Hours”. Here is an example from PG&E.
Unfortunately, the “Peak” rates are usually at the beginning and/or end of the day, when your system is producing the least amount of energy. Below is an example of the energy production of a solar system during different hours of the day.
With battery storage, you can manage when you’re sending energy back to your home and the grid, so you can store energy during the day, and utilize the stored solar energy when it’s needed most.
Peak-Demand rates are charges that are incurred based on the most power used during a certain time period. In other words, your monthly utility rate would depend on the highest amount of energy taken from the grid within a short time period during that month.
Demand charges can be mitigated through battery storage by controlling the energy draw from the grid, which is called Peak-Shaving. In other words, Peak-Shaving is when a system uses available energy from battery storage to lessen the need for energy from the grid, as shown below.
A major perk of having battery storage is the possibility for self-consumption, where minimal energy is needed from the grid, if at all. Battery-based systems can generate power during the day and any excess power can be saved in an uninterruptible power supply of battery storage. Any energy that is not used by the end of the day can be sold back to the grid. Adding batteries to your system can enable profitable energy-independence which could greatly reduce your monthly utility bill.
Ease of Installation
Fortunately, since battery-based solar systems are very close in design to conventional grid-tied systems, battery storage is an easy addition to your existing system.
If you are retrofitting your system, the battery inverter, sometimes referred to as a “hybrid inverter”, will be positioned in between the current string inverter (or microinverters) and the AC disconnect. The battery bank will connect directly to the battery inverter as shown below.
Common hybrid inverters seen in the field today include the Sol-Ark 12k, Outback Radian, and Schneider Electric Conext inverters. These can be coupled with existing solar microinverter and string inverter setups or directly to existing solar panels with the appropriate equipment.
Equipment Brand Recommendations
Here is a list of brands for battery inverters that can be used for energy storage applications:
Battery Inverters (AC Coupling)
For information on the general set up of systems with battery storage, please visit our article Off-Grid, Battery-Backup, and Hybrid Solar Inverters for more information.
To design your individual PV system, simply register at renvu.com/register and utilize our Solar Kit Guide (SKG) tool to generate a customized quote in just minutes. To retrofit your solar system, check out our NEW Battery Upgrade Guide (BUG) tool.
If you need help getting started, you can watch our video tutorial on how to use the Solar Kit Guide, or contact the Renvu sales team at firstname.lastname@example.org or 855-755-5855.