How Does Solar Energy Storage Systems Work

How Does Solar Energy Storage Systems Work


What is a Solar Energy System?

All around the world, solar energy is a renewable power source that is known to be inexpensive and clean. This energy can be used to generate electricity, thermal storage as well as in batteries. A potential location can be seen anywhere on the surface of the earth where sunlight hits. This represents a vast and infinite source of power. It takes thousands and hundreds of years for gas, coal and oil to form which can be easily depleted when used continuously without replacement compared to renewable energy resources such as hydropower, wind as well as solar power which does not deplete when used. What makes solar power by nature a renewable energy is the certainty that there will always be consistent sunlight on the surface of the earth to convert into electricity to be used for the present and also enough in the future.

The entire world can literally be lit up by the amount of sunlight that strikes the earth's surface in an hour and a half for one full year. There are different ways in which solar energy can be captured, the most common seen in photovoltaic solar panel systems which convert sun rays into electricity to be used, through mirrors that concentrate solar radiation and also solar hot water systems designed in some buildings as thermal applications to heat indoor fluids.

Types of solar energy system

Solar energy systems are available in various sizes and shapes. Residential systems are basically found on rooftops, businesses also install solar panels, utility companies build large solar power plants to provide electrical energy to their various customers across the grid.

Solar energy technology are of two major types:

  • Photovoltaics Basics

Photovoltaics widely known as PV is utilised in solar panels, when sun rays hit the solar panels, energy from the sunlight is absorbed by the PV cells in the panel. This creates a kind of energy that charges the cells to go into random motion in response to an internal electrical field in the cell thereby causing electrical flow.

  • Concentrating Solar-Thermal Power Basics (CSP)

This type of solar energy system uses mirrors to reflect and concentrate sunlight onto receivers which collect solar energy and convert it to heat, it is primarily used and seen in large power plants to produce electricity which can also be stored for use later.

How it Works in Energy Generation

Sunlight is harnessed by solar power using Solar Photovoltaic (PV) technology which converts solar radiation to electricity using semiconductors.

A solar panel (module) comprises a layer of silicon cells, a metal frame, a glass casing unit, and wiring to transfer electric current from the silicon. Silicon being a non-metal has conductive properties which allows it to convert sunlight to electricity. When light hits a silicon cell, electrons in the silicon are set in motion, thereby initiating a flow of electric current. This is known as the “photovoltaic effect,” this effect gives a wide explanation on the general function of solar panel technology.

When Solar panels are connected in an arranged manner in the sunlight, voltage and current in the form of Direct current (DC), the solar panels are then connected to an inverter which then converts the DC to AC which can be used at home for appliances and equipment.

The photovoltaic process works through the following broad steps:

  1. The silicon photovoltaic solar cell absorbs solar radiation from the sun.
  2. When the sun’s rays interact with the silicon cell, electrons begin to move, creating a flow of electric current.
  3. This direct current (DC) is captured by wires and fed to a solar inverter to be converted to an alternating current (AC).

How Does Solar Energy Storage System Works

Solar energy technology doesn’t just end with generating electricity only by PV or CSP systems, The system is integrated into homes, businesses, and existing electrical grids.

You would be interested to know what happens if you're not home to use the electricity your solar panels are generating every sunny day or what happens at night when there is no sunlight and the solar system is not generating power in the meantime; a system called net metering is used here.

The electricity generated by solar cells can be stored using batteries or supercapacitors and then can be released as electrical energy when it is cloudy or at night.

Two ways to store solar energy for later use.

  • First method of harnessing and storing solar energy is that solar power can be stored as thermal energy of concentrated sunlight in the heat capacity of a molten salt which is the liquid form of an ionic compound like sodium chloride(NaCl) at a high temperature. When electricity is needed later, using a heat exchanger to generate steam, the heat is transferred from the molten salt to water.
  • Second process is to employ sunlight to produce fuel. For instance, a photoelectrochemical cell which uses solar energy to split water into hydrogen and oxygen gases, and these can be stored as fuels. In a device known as a fuel cell, these gases are recombined to generate electricity. The by-product of the fuel cell reaction is simply water which makes it environmentally friendly.

N/B: Solar panels do not store energy but solar systems do.

During peak daylight hours, a typical grid PV system frequently produces more energy than it's needed at a time and then excess energy can be fed back into the grid to be used later at night or on cloudy days.

Adding storage to a solar system enhances a lot of benefits as people can store their own energy on site which gives more advantage in powering homes when there is power shortage and reduces the reliance on normal grid electricity. Some storage systems apart from the ability to store power for later use, they could also include software monitoring which monitors home energy utilization, solar production, utility rates in order to know which power source to use at a particular time and to reduce high charges.

Frequently Asked Questions About Solar Energy

  • How Does Weather Affect Solar Energy?

Weather conditions can impact the amount of electricity a solar system produces, but to some certain extent. A clear sunny day is the perfect condition for solar energy production but like most electronics, solar panels are actually more efficient in cold weather than in warm weather which allows the panel to produce more electricity at the same time. At a high temperature, the panel generates less voltage and produces less electricity.

Solar panels do not produce more electricity in winter than in summer even though they are known to be more efficient in cold weather, the sunnier weather is usually seen in the warmer summer months.

  • What Are the Benefits of Storing Solar Energy?

Getting the most out of any solar panel storing the excess energy is quite important, this brings about a total guarantee of steady power,reduces cost, more efficient energy grids and reduces environmental pollution as a result of less carbon combustion.

  • How long can solar energy be stored?

In any energy transfer system there is always energy lost which cannot be 100% efficient as a result of loss of energy in the form of leaks during storage and release. Theoretically, as long as the potential energy is maintained, solar energy stored mechanically can last for quite a while.

  • How long do solar batteries last?

A standard solar battery can last 15-30 years, depending on type as well as how it is being used, handled and maintained. Also a standard battery when charged can last for about 1-5days.

  • How many solar batteries do I need?

This entirely depends on specific needs varies dramatically based on some factors such as your desired storage capacity, backup duration as well as backup load.


Unlike some dangerous electricity generating technologies that are not environmentally friendly, solar energy systems are a well-established technology that is intrinsically safe. Harnessing the clean source of power that is produced by the sun can be quite challenging but thankfully technologies are being employed which brings utmost solutions to these challenges to bring about proper effectiveness when needed either for commercial or industrial use.

Solar energy system, when employed properly in an area, can help create job opportunities to boost the economic growth of a country. It can be used in both small and large scale, reduces cost of electricity, generates back-up power when paired with storage for nighttime and in cold weather when there is no sunlight.

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4th Oct 2021 Jennifer Eyo

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