WHAT IS A SOLAR ENERGY STORAGE SYSTEM?
SOLAR ENERGY STORAGE 101
RESIDENTIAL BATTERY ENERGY STORAGE
Energy storage makes that electricity usable after sunset. Without a way to store power, excess solar energy is exported to the grid or lost. With the right solar energy storage system, that same energy can be used at night, to help lower and offset high energy bills, and when the grid goes down. Solar energy storage turns solar from a daytime upgrade into a full-time power resource. Think of solar panels as the paycheck and battery storage as the savings account.
WHY EFFICIENT ENERGY STORAGE MATTERS
Energy efficiency determines how much usable energy actually reaches your home. Well-designed solar energy storage systems reduce wasted electricity, lowers utility bills, and improves reliability. Poorly-sized energy storage systems lose energy through unnecessary conversions or short cycling, increasing long-term costs (Denholm et al.).
If you’re installing a solar energy storage system yourself, be sure to use a solar panel and battery-sizing tool to maximize your efficiency. And, if you’re working with a trusted solar installer, make sure to have a conversation about what the right size hybrid inverter (12K-2P, 15K-2P, or 18K-2P) and number of batteries will meet your needs.
TYPES OF SOLAR POWER ENERGY STORAGE SYSTEMS
BATTERY STORAGE SOLUTIONS
Battery systems are the most common way to store solar energy at home. Battery storage allows homeowners to store electricity from solar panels and use it later, whether overnight or during a power outage.
- Lithium-ion batteries dominate residential systems because they are compact, efficient, and long-lasting.
- Lead-acid batteries cost less upfront but wear out faster and require more maintenance.
- Flow batteries last a long time but remain expensive and rare in residential installations.
THERMAL STORAGE SOLUTIONS
Thermal storage captures heat instead of electricity.
This is an option used primarily by large utilities and utility-scale commercial projects. Solar thermal systems store heat in materials like water or molten salt, then release it later for heating or power generation.
MECHANICAL STORAGE SOLUTIONS
These systems store energy by moving water uphill or compressing air underground.
Mechanical storage methods include pumped hydro and compressed air. Here too, this is an option used primarily by large utilities and utility-scale commercial projects.
COST COMPARISON OF BATTERY ENERGY STORAGE METHODS
Research shows that battery storage introduces some energy losses, but value-driven hybrid inverters and well-designed energy systems still deliver meaningful gains in reliability and cost control (Denholm et al.).
BATTERY TYPE |
KEY CHARACTERISTICS |
|---|---|
| Lead-Acid Batteries | Low upfront cost, higher replacement frequency |
| Lithium-Ion Batteries | Higher initial cost, better efficiency and longer life |
| Grid-Tied Systems w/ Net Metering | No storage equipment, limited backup capability |
SOLAR ENERGY STORAGE SYSTEM FAQS
How Is Electricity Stored
from Solar Panels
Electricity from solar panels flows through an inverter, which converts direct current (DC) into alternating current (AC). When production exceeds household demand, a battery system captures the extra electricity before it is sent to the grid. Later, when solar output drops, the battery supplies power back to the home.
How to Preserve Solar Energy
for Later Use
Preserving solar energy means limiting losses during charging, storage, and discharge. Proper battery sizing, efficient inverters, and smart energy controls all play a role. Systems designed around real household usage patterns tend to perform better than oversized or mismatched setups.
How Long Can Solar Energy Be Stored
Battery systems typically store energy for hours or days, depending on capacity and demand. Most residential systems are designed for daily cycling, storing excess daytime production for nighttime use. Seasonal storage is technically possible but rarely economical for homes.
Most affordable, value-driven ways
to Store Solar Energy
- 48V Lead-acid batteries are the lowest-cost way to store solar energy. However, the lower price point comes with tradeoffs in energy efficiency, battery lifespan, and safety. Improper wiring or ventilation can create serious hazards.
- Lithium-ion energy storage systems offer superior long-term value and ROI for a higher upfront cost.
WHY "ONE SYSTEM THAT DOES IT ALL" ISN'T ALWAYS THE BEST CHOICE
On paper, it’s tempting to think: Why not just install the biggest, most powerful inverter, all the battery back-up, and call it a day? In practice, you end up with a system that does a lot things, but nothing that is optimized for your needs.
HOW TO CHOOSE THE RIGHT ENERGY STORAGE SYSTEM
The answer everyone loves to hate, but engineers respect, is: “It depends.”
And it depends for good reason. Energy storage systems are not one-size-fits-all because all homes don’t use energy the same way. Don’t face the same utility rates. And don’t have the same priorities.
A solar energy system for your home needs to be designed to meet the needs and goals you want to accomplish. Otherwise, you’ll end up with a really powerful system you think will do everything well, and often ends up doing nothing optimally. Not too mention? It costs more than it should.
HOME GOAL |
PRIMARY FOCUS |
KEY CONSIDERATIONS |
DESIGN OUTCOME |
|---|---|---|---|
| Backup-Focused Homes | Keeping essential and whole-home loads running during grid outages |
|
System is designed to carry the house during outages, not just reduce the electric bill |
| Savings-Focused Homes | Lowering monthly utility costs and improving return on investment |
|
Oversizing storage can reduce ROI by adding unused capacity and higher upfront costs |
| Hybrid Goals (Most Homes) | Balancing outage protection with ongoing energy savings |
|
Thoughtful system design delivers resilience and savings without unnecessary cost |
THE NEXT 10 YEARS OF SOLAR ENERGY STORAGE
Solar energy storage should become more affordable and more common in U.S. homes. Like any technology, the longer the lifespan timeline, the cheaper it becomes. Utilities are increasingly relying on distributed energy resources (DERs) to support the grid, placing greater emphasis on flexible, well-managed storage systems. Battery chemistry, energy management software, and grid integration continue to advance. New systems are safer, more efficient, and easier to control. Costs are declining as adoption increases.
Works Cited
Denholm, Paul, et al. “Storing Solar Power Increases Energy Consumption and Emissions.” Cockrell School of Engineering, University of Texas at Austin, 2022.
“Solar Integration: Solar Energy and Storage Basics.” Energy.gov, U.S. Department of Energy.