Solar Battery Storage: Benefits, Costs and Advantages

More homeowners and businesses are installing solar battery storage systems with their photovoltaic (PV) systems as solar energy becomes more affordable and accessible. Energy demand can occur even after the sun sets, while solar panels produce electricity in the day. This mismatch can be resolved by using a solar battery, which stores excess solar energy and releases it when it is needed.

Or is there a point in investing in solar battery storage? There isn't a single right answer: It depends on electricity costs, energy use, the size of the solar system, battery capacity and local utility policies. This guide provides the advantages, disadvantages, costs, and uses of solar battery storage to help homeowners and business owners make an informed decision.

What Is Solar Battery Storage?

A solar battery storage system is a bank of batteries that store electricity produced by solar panels for later use. In sunny conditions, the solar panels can generate excess electricity which can be sold back to the national grid. A battery may store some of that power, rather than sending it all to the grid.

As solar generation decreases (for example, at night, cloudy weather, outages), the stored electricity can be used to power appliances, lighting, equipment and electrical loads.

A solar-plus-storage systems is typically comprised of:

• Solar panels
• Solar inverter
• Battery storage system
• Battery management system
• Monitoring and energy management equipment
• Electrical protection and installation components

The energy density, safety features, and extended cycle life make lithium-ion batteries especially popular, especially lithium iron phosphate (LiFePO4) batteries.

Key Benefits of Solar Battery Storage

1. Store Excess Solar Energy

The most important benefit of battery storage is the ability to store excess solar energy.

If no battery exists, the extra electricity generated from the sun can be fed back into the grid depending on the local system and electricity contract. Homeowners can store that energy in a battery for later use.

A household, for instance, can produce a lot of solar energy at midday when there is not as much energy use as there will be at night. The excess power can be stored in the battery and released at night when the electricity demand is high.

This helps the property to utilize its own solar energy.

2. Reduce Electricity Bills

Solar battery storage system can save the electricity bills from the grid.

This is especially useful in regions where electricity charges are increased during specific times of the day or year. Some batteries can store energy when the sun is producing energy, and use it when electricity from the mains is more expensive.

The actual savings will vary according to:

• Local electricity rates
• Time-of-use pricing
• Solar generation
• Household consumption
• Battery capacity
• Battery efficiency
• Utility compensation for exported solar power

Therefore, battery storage should be evaluated based on the property's specific energy profile rather than using a universal savings estimate.

3. Provide Backup Power

Another major advantage is backup power during grid outages.

When properly designed and installed, a solar battery system can keep selected electrical loads operating when the utility grid fails. Depending on system capacity, backup power may support essential appliances such as:

• Refrigerators
• Lights
• Wi-Fi routers
• Security systems
• Medical equipment
• Heating or cooling equipment
• Essential business equipment

Solar panels can potentially recharge the battery during a prolonged outage, depending on system configuration and weather conditions.

However, not every solar installation automatically provides backup power. The inverter, battery, transfer equipment, and electrical design must support backup operation.

Solar Battery Storage Costs

The cost of a solar battery storage system varies significantly.

Important cost factors include:

Battery capacity: A larger battery generally costs more because it can store more electricity.

Power output: Two batteries with similar energy capacity can have different costs depending on how much power they can deliver simultaneously.

Battery chemistry: Lithium-ion and LiFePO4 technologies are common, but different battery technologies have different performance and pricing characteristics.

Installation: Electrical work, permits, wiring, equipment upgrades, and labor can contribute significantly to the total project cost.

Inverter requirements: Some systems require additional or specialized inverter equipment.

System configuration: Whole-home backup typically costs more than backup designed only for essential circuits.

Rather than comparing batteries only by their purchase price, consumers should consider the total cost of ownership. Useful metrics include cost per usable kWh, expected cycle life, warranty period, efficiency, and installation expenses.

Is Solar Battery Storage Worth It?

Solar battery storage can be particularly attractive when electricity prices are high or when grid electricity is significantly more expensive during evening peak periods.

For example, a homeowner with solar panels may generate excess electricity during the afternoon but consume more electricity after work. A battery allows the homeowner to shift solar energy from the daytime to the evening.

Battery storage can also be valuable where grid reliability is a concern.

However, batteries are not automatically the most economical choice for every property. If electricity prices are low, solar export compensation is favorable, or energy consumption is minimal, the financial payback may be longer.

A proper evaluation should compare:

Solar-only system vs. solar-plus-battery system

and consider expected electricity savings, battery replacement costs, incentives, and system lifespan.

Advantages for Commercial Solar Systems

Solar battery storage is not limited to residential applications. Commercial and industrial properties can benefit from energy storage as well.

Businesses often have significant electricity demand and may face demand charges or time-based electricity rates. Battery systems can help businesses manage energy consumption and reduce reliance on grid electricity during expensive periods.

Commercial battery storage can provide several advantages:

• Peak demand management
• Greater solar self-consumption
• Backup power
• Energy cost control
• Improved energy resilience
• Better utilization of large solar systems

For businesses with substantial daytime solar production and evening electricity demand, energy storage can improve the overall value of a commercial solar installation.

Solar Battery Storage and Energy Independence

Another important advantage is greater energy independence.

A solar panel system without storage generally remains connected to the electricity grid. Solar batteries allow users to store electricity and use it according to their own energy needs.

A larger battery combined with a properly sized solar system can reduce dependence on grid electricity, although complete energy independence requires careful system design and sufficient generation and storage capacity.

For off-grid properties, battery storage is especially important because it provides energy when solar production is unavailable.

How Long Do Solar Batteries Last?

Battery lifespan depends on chemistry, operating temperature, charging and discharging patterns, depth of discharge, system design, and maintenance.

Modern lithium-based solar batteries are generally designed for many years of operation. Manufacturers commonly provide warranties based on a combination of years, energy throughput, or remaining capacity.

When comparing battery products, buyers should examine:

• Warranty duration
• Guaranteed remaining capacity
• Cycle life
• Usable capacity
• Round-trip efficiency
• Operating temperature range
• Safety certifications
• Monitoring capabilities

These specifications can be more useful than simply comparing the initial battery price.

How to Choose the Right Solar Battery

Selecting the right battery requires more than choosing the largest available capacity.

First, determine daily electricity consumption. Then evaluate how much solar electricity is currently being exported or remains unused.

Next, consider your primary objective:

Lower electricity bills: Focus on usable capacity, efficiency, and compatibility with time-of-use rates.

Backup power: Focus on power output, backup functionality, and which circuits need to remain operational.

Maximum solar self-consumption: Choose storage capacity based on excess daytime solar generation and evening consumption.

Commercial energy management: Evaluate peak demand, operating schedules, electricity tariffs, and load profiles.

Professional system sizing can help prevent both undersizing and unnecessary battery capacity.

Future of Solar Battery Storage

Energy storage is becoming a more significant component in today's electricity systems as solar energy is being increasingly deployed.

Batteries continue to advance rapidly and energy management systems are becoming more intelligent. Upcoming solar-plus-storage installations are likely to offer better monitoring, automated load control and better integration with electric vehicles and ‘smart homes’.

Meanwhile, for businesses, battery systems could grow in significance in terms of energy cost management and resilience.

Conclusion

Solar battery storage offers a number of significant benefits such as higher solar self-consumption, lower grid electricity consumption, backup power, energy cost management and higher energy independence.

The biggest hurdle is the initial investment. The economic viability of a battery installation will vary with energy costs, energy generation from photovoltaics, battery cost, incentives, and energy usage.

When thinking about solar, homeowners and businesses should be looking at the entire system and not the battery cost. Once customers have the usable capacity, efficiency, warranty, lifespan, installation prices, and potential energy savings of solar battery storage, they can see if it is a good value for their property.

In the end, the solar panels produce the renewable power, and the batteries provide that power when it's needed most. When combined with battery storage, solar energy can achieve a more flexible, resilient, and efficient energy system.