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In recent years, residential energy storage systems have become increasingly popular, especially in the United States, South Africa, Australia, and across Europe.

The primary reasons for this trend include:

Extreme weather conditions

Severe weather puts power grids under the test. The world is experiencing exponentially high power outages caused by ice storms, tornadoes, wildfires, hurricanes, and flooding. The Texas ice storm and storm Filomena in Spain resulted in power outages for days, leaving people to fend for themselves without water or electricity.

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Source: Solis

High cost of electricity

High prices of electricity have become a major pain point for homeowners across the world. Energy price across the world in 2020 was estimated to be €0.113 ($0.137)/kWh on an average. Germany had the highest electricity price at €0.304 (~$0.365)/kWh. The cost of electricity in most European countries has continued to rise over the past ten years.

Falling cost of solar and energy storage

The reduction in the cost of solar and energy storage systems coupled with policy support from forward-thinking governments make the upfront cost more palatable. It also reduces the payback period for the average homeowner. Government programs such as the Australia energy storage subsidy reduces a 10 kWh energy storage system by AUD 5,000 (~$3,867).

Due to the above key reasons, homeowners are quickly realizing the benefit of a home energy storage system. For new systems, the obvious choice is to install a hybrid inverter that takes inputs from both solar photovoltaics (PV) and batteries. For someone who already owns a grid-tied solar system, upgrading and adding an AC-coupled battery inverter (such as the Solis RAI) is a simple and cost-effective way to obtain an energy storage solution. With just a few additional pieces of equipment alongside an AC-coupled inverter, upgrading an existing solar PV system to include storage couldn’t be simpler.

Required Equipment – Solis RAI example

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Source: Solis

System Topology

While upgrading the grid-tied solar system to an energy storage system, the only part that changes is the AC-coupled battery inverter add-on. The existing solar PV system doesn’t need to change at all. The AC-coupled battery inverter is installed alongside the batteries, which is then connected directly to your panel or mains. If the customer wants critical load backup, then those loads will be moved to the backup port of the RAI. This provides customers the opportunity to select loads that they define as “critical”. Critical loads will remain online during a grid failure until the solar PV generation is null and/or the battery is drained out of charge. Examples of critical loads would be refrigerators, hot water tanks, emergency lighting, etc.

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Source: Solis

For a detailed understanding of the installation process, you can visit the Solis website ( to find out more about the Solis AC-coupled inverter through the datasheet, compatible battery list, and user manual.

Benefits of Expanding into Solar PV Energy Storage Systems

Use energy storage devices to adjust the peak and valley power demand of the grid and enhance the capacity of photovoltaic energy absorption.

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Source: Solis

Improve power reliability and power quality of clean energy.

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Source: Solis

Improve self-consumption ratio and reduce electricity bills.

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Source: Solis

Enable emergency power supply in case of a grid failure.

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Source: Solis

Economic Benefits

Solar energy storage systems can reduce the cost of electricity and improve the stability of the homeowner’s power supply. Moreover, the cost recovery period is shortened and even more so if a local government subsidy is available. On average, the cost recovery period of a grid-tied inverter is five years globally, but it can increase or decrease based on subsidies. However, if the AC-coupled extended energy storage system is added, the recovery time is reduced. This is a more attractive option for all homeowners – all while accelerating the world’s journey towards a more sustainable future. 


For homeowners who already have a solar PV system installed, there has never been a better time to upgrade that system to an energy storage solution. With an AC-coupled RAI battery inverter solution from Solis, this transition is simple, cost-effective, and delivers energy security as well as peace of mind. Whether it is a simple grid failure due to localized works or a major weather system causing power failure, Solis will ensure homeowners that critical loads remain connected and online without any downtime.


This article is sponsored by Ginlong Technologies, solar inverter manufacturers.


Image credit: Ginlong Technologies