Solar energy can also be stored in electrochemical batteries. When solar energy is pumped into a battery, a chemical reaction between battery components stores the energy. The reaction reverses when the battery is discharged, allowing current to flow out of the battery. The ability to sell excess energy to the utility company consolidated the economic case for residential solar, but also reduced the need for personal storage.
As an added benefit, solar batteries are a much quieter backup power option than gasoline-consuming generators. Some utilities have imposed new tariffs on solar energy, while others have tried to completely gut state net metering programs. Otherwise, solar batteries are still quite expensive, so they won't have a good financial outcome for most homeowners. One of the keys to achieving high levels of renewable energy on the grid is the ability to store electricity and use it at a later time.
While there are many benefits of solar batteries, you should consider whether those benefits outweigh the costs. For example, by heating or cooling a building before an anticipated peak in electrical demand, the building can “store that thermal energy so that it doesn't need to consume electricity later in the day. For example, a photoelectrochemical cell uses solar energy to divide water into hydrogen and oxygen gases, which can be stored as fuels. Lithium-ion batteries can store solar energy through a series of chemical reactions, in which lithium ions move through an electrolyte solution inside the battery.
One of the drawbacks of solar energy systems is that the Sun does not provide a constant flow of energy. More than 10 million people come to EnergySage every year to learn, buy and invest in solar and household batteries. We also take a more technical look at what exactly is happening inside the battery to store that energy.