Where Do Solar Panels Store Energy?
It’s common to hear people speak of solar panels as though they were all you need to go solar. However, solar panels are just one piece of the picture. A solar panel simply captures the sun’s energy and converts it into electricity or heat. Sometimes you can use that energy right away. But the sun isn’t consistent, and neither are your energy needs. On bright, sunny days, your panels may produce more than you need at the time. At night or on a dark, stormy day, your panels may produce little to nothing for a while. However, those are often the times when you need the energy most.
Clearly, just creating energy from the sun isn’t enough. You also have to have some way to store that energy so it’s available for use when you need it.
Have you ever asked yourself, “How is solar energy stored?” If so, you’re in the right place, because that’s exactly what we’re going to explore here.
Solar thermal storage
Have you ever walked barefoot on the beach after a sunny day and felt how warm the sand stays even hours after the sun sets and the air gets chilly? That’s because the sand absorbs and traps the sun’s heat, and releases it slowly — effectively storing the warmth. This is an example of solar thermal energy storage found in nature.
“Solar thermal” refers to generating heat — as opposed to electricity — from the sun. Many of the big commercial solar energy plants are actually solar thermal devices. They use huge parabolic solar collectors to collect the sun’s heat, and use that heat to create steam, which in turn powers a generator to produce electricity additional resources. Instead of sand, these energy plants use materials such as thermal oil or molten salt to store the sun’s heat.
That kind of solar thermal energy isn’t practical for residential use, but a solar water heater is. In a solar water heater, special panels are used to heat fluid directly with the sun. The heat is then transferred to a domestic hot water tank for use in showers and laundry. The water is thus used as an effective solar energy storage device.
Solar battery storage
The most popular way to use solar energy is as electricity, or photovoltaics. Storing electricity effectively requires a more complex technological solution than storing heat. The most widespread solar power storage method is the battery.
In the early days of residential solar, people would use whatever batteries they could find to store their solar energy. 9-volt car batteries were popular, but they were not optimal. Even when companies started manufacturing batteries specifically for solar systems, the early ones were expensive, bulky, short-lived and required frequent maintenance.
Battery technology has improved by leaps and bounds since then. Today, many types of batteries are available to provide excellent power storage for your solar system, including lead-acid, lithium-ion and redox flow batteries. Look for even more improvements in battery performance, safety and longevity in coming years.
Another way to store solar energy is a fuel cell. Solar power is used to split water into hydrogen and oxygen. The hydrogen is stored in a fuel cell to be converted into electricity at a later time. Fuel cell technology is still in its infancy, but many promising breakthroughs are happening — and it’s reasonable to expect widespread use of solar fuel cells in the near future, especially in electric vehicle applications.
Using the grid to “store” solar power
Finally, let’s consider the electrical grid. While the grid is technically not a storage device, it’s so large that for practical purposes an individual business or household with solar panels can use it as one. In other words, when you’re connected to the grid it can absorb any excess energy you’re producing at any given time. And if you need more than you’re generating for a time, it’s there for you to draw on. It’s a win-win arrangement because it allows you to use as much electricity as you want when you want, and helps maintain the resiliency of the grid. If net metering is available in your area, it also allows you to sell your excess energy for a profit.
It’s possible to use more than one type of solar power storage at once. For example, the latest trend in solar is to use a hybrid grid-tied/battery system. That way, you have power when the grid goes down, but can still enjoy the advantages of grid connection.
Which type of solar energy storage is best for you?
Which solar storage solution you use will depend on what type of solar energy system you have — as well as your lifestyle, budget, space and other needs. In particular, solar battery technology is constantly changing, so if you’re interested in a battery system, you’ll want to speak with an expert who is up to date on the latest types and models available. To discover more about the available solar storage solutions that will work best for your needs, call us at (410) 560-9032 and ask to speak with one of our solar storage experts. Or, request a free solar estimate online, and we’ll be in touch with you soon!