Hybrid systems Off-grid systems Batteries

Solar batteries in 2023: Is it time yet?

01 May 2021
6 min
Beginner

Andrey GorichenskiAuthor

Just a while ago it wouldn't make much sense to buy batteries for a solar installation without a strong reason. Batteries were simply too expensive and probably would never pay for themselves. However, over the last decade the price for lithium-ion batteries have dropped by 90%. What is more, after a shaky 2020, many of us switched to working from home, and some felt the need for a constant power supply. Well, they are only a few reasons to include solar batteries in the Shopping List 2022.

Solar batteries are good when you can't rely on the grid

Most residential solar installations in the US are grid-tie, which means that the house is connected to the grid and there is no energy backup. There are two main reasons why grid-tie systems are popular: batteries are expensive and net metering helps to save money.

However, the grid-tie type of solar installation isn't ideal. First of all, you depend on the utility company, which sets the rates and terms for net metering. Second, and more important, if the grid breaks down, you are left without electricity until it is repaired. Your solar system won't save you, because the grid-connected inverter will just shut down due to safety reasons.

To become more independent, some homeowners pair solar panels with batteries. Here are some situations where adding solar storage can be especially beneficial:

Remote locations. In some places, there is no utility grid at all. An off-grid solar system, where the generated energy is stored in batteries, is the only way out. Solar panels run household appliances during the day, and batteries power the home at night.
Power outages. In some places, homeowners experience constant power outages because of run-down power lines or a harsh environment. To save yourself from sitting in the dark house and waiting for the power to come back, you can add batteries to the solar panels and get a hybrid system out of a grid-tie one. The option to sell the energy surplus remains, and you have an energy backup for emergency situations.
Uninterrupted power supply. In some situations you really can't risk losing power supply, even when the grid generally works fine. For example, a hospital can't have its medical equipment unpowered, or a factory can't risk their production lines coming to a standstill because of a small blackout. Energy storage helps to avoid this kind of situation.

Net metering – selling excess solar energy into the grid

Batteries are better than generators all around

A generator is the easiest thing to use during a blackout. However, these solar batteries benefits prove that loud gas and propane generators have already become obsolete:

Batteries are silent and don't smell.
They don't need any fuel that might be hard to find at the time of natural disasters.
Solar energy is green, so you contribute to saving the planet.

As a backup to a solar system, batteries seem like a better deal even in terms of cost. The price of a generator depends on its power capacity, which comes roughly at $1,000 per kW – and we aren't taking fuel into account. You can get a 10 kW solar battery for around $6,000–$7,000 with a 10 year warranty.

In certain situations solar batteries pay for themselves

Getting solar batteries for home usage is rarely going to save you money – it is primarily a safety measure. When you have access to the net metering program, adding a battery to the grid-tie system can't be economically justified. However, batteries might pay for themselves if:

your utility company sets exorbitant peak rates. If the solar system doesn't cover your energy needs during peak hours, you could avoid paying extra to the utility company by taking electricity from the batteries.
your utility doesn't offer net metering or limits it. This is especially true for those who spend a lot of energy at night hours. Solar energy can't be utilized after dusk without batteries. If net metering is limited, and the generated solar energy cannot be spent efficiently during the day, it's not reasonable to let it just disappear into nothingness.

Let's say you are about to get a solar battery for your house. How much is it going to cost you? Most solar batteries are now lithium-ion, ranging from $6,000 to $20,000. The price depends on the size, quality, and warranties. Again, $6,000–$7,000 is a reasonable price for a 10 kW battery. Providing a backup for everything in your home, however, might be too expensive. After all, an average daily energy consumption for an American house is around 30 kWh, according to EIA. What solar experts propose is to carefully size a battery bank, taking in account only essential appliances that you are going to use during a power outage.

So, what's the bottom line? Unlike PV modules, solar batteries shouldn't be considered an investment that pays for itself and brings in money. Instead, they are a great tool to make your home more energy sustainable and independent. They are not a must, but they can make your life easier if you are having troubles with the grid. During the last decade, we've witnessed a steep decline in prices for solar batteries. This trend can continue and make solar storage an even more reasonable choice.