Can solar power be stored?
The sun produces insane amounts of energy, generating more power in one hour than the Earth would need in an entire year. Many scientists think solar power is the solution to our dependency on fossil fuel. Even though many companies and homeowners are installing solar panels on their roofs, the trend is relatively slow. That is because solar panels are still not economically accessible to everyone, and using solar power may not seem like the best choice for everyone.
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For instance, people who only use electricity in the morning and evening may find it inconvenient to install a solar system that only works during the day. In that case, they would still be producing electricity and selling it back to the grid, but the power they would actually be using is still the old, “dirty” one provided by energy companies. Therefore, you would still benefit from a solar panel installation but your home would not fully rely on solar energy. If that concerns you, there is a simple solution available to you: solar batteries.
What are solar batteries?
Solar batteries are storage tanks that store the solar power generated during the day, so that you can use it when the sun goes down. This translates into almost total independence from the grid (usually batteries can cover 70-100% of your energy needs) and even higher savings on energy bills. Moreover, you won’t have to worry about power cuts and expensive or inaccessible power in remote areas. The batteries work as emergency energy storage systems, which can be particularly helpful for companies who are strongly affected by power cuts, but can be a huge help to anyone. Just think about how your food spoils in the fridge due to long power cuts. The batteries can be used as an emergency backup for days, since they are recharged continuously by the sunlight.
Photo credits: Tesla Motors © 2015
How do solar batteries work?
When the sun is shining, solar powers will produce electricity that you can use to power your home. The excess energy is fed to the batteries. As soon as they are fully charged, the excess power is sold to the grid. During dark hours, the batteries will provide you with the free, clean power stored before, and if it runs out you will automatically be reconnected to the grid. That may happen during the winter, but good storage systems usually store 100% of the energy you need during the summer, and 70% in the winter. You can find solar batteries suitable for any power need: from solar powered boats and campers to hospitals, you can choose systems of many different sizes. It is important to keep in mind that batteries need special care. They should be kept at a constant temperature, with low humidity, which is why indoors types are the best performing option. Moreover, the batteries usually work best when they are fully charged, so you should not discharge them too much (that is, below 20%), to preserve battery life.
Types of solar batteries
There are four basic types of batteries you can choose from, depending on the amount of energy you generate.
- RV/Marine/Golf Cart: these batteries are only suitable for small systems, such as boats and campers. They have a short life cycle, since they are not designed to sustain many continuous cycles, but they are the best option for a small system and a limited budget.
- Flooded: these industrial type batteries are designed to last longer and are reasonably priced. Since they release gas while charging, they must be placed outside or in a ventilated room.
- Gel: unlike flooded batteries, these type does not release gas and can therefore be placed inside. That also translates into better performance, since the batteries maintain a constant temperature.
- Absorbed Glass Mat: they are probably the best batteries on the market, since they do not release gas, are leak-proof and perform better. They last longer and have a higher quality compared to gel batteries. Of course, they are also more expensive. Since they are the most secure batteries, they are even used for airplanes and hospitals.
While very useful, many solar batteries available on the market have the disadvantage of being expensive and not very space-efficient. In fact, you would need either a battery room in your house to store them, or keep them outside thus reducing their performance. However, new models such as the Tesla Powerwall being launched this summer are much smaller and powerful, while keeping prices stable. These new entrants are stylish, slim and can store five times more power than traditional batteries. Moreover, they can be stacked together to provide more energy: in Powerwall’s case, you can install up to 9 devices, which would amount to a total of 90kW. Tesla is developing its technology even further, by introducing the Powerpack, an infinitely scalable battery created to fit the needs of large companies and to build battery “farms” that could power large areas.