As a homeowner, you will certainly ask yourself again and again whether you should buy an electricity storage device for your solar powered generator system before you buy it or while using your solar system. A storage system is known to have many benefits, but is it worth the cost? Or is it possible to get along very well with a solar system without a storage tank?
Why electricity storage?
A power storage unit is used to store excess solar power that is not used immediately after generation. For example, if the photovoltaic system produces more electricity than is consumed. Or if you are not in the house when the sun is out and do not need electricity.
In this way, electricity can be provided for a later point in time. The electricity can then be used in the evenings and at night when the sun is not shining, and no solar energy can be generated at that time.
The solar system without electricity storage
Without solar storage, the continuously generated solar power must be used immediately. Otherwise, it is wasted or fed directly into the public grid, reducing self-generated electricity’s self-consumption.
No electricity can be converted in the evening due to the lack of sun, so you have to use the electricity from the public grid. The use of electricity must be well planned, as the photovoltaic system only produces solar electricity that can be used during the day.
Without additional storage, you should ensure that solar power is used directly. But use most of the energy during the day and don’t need any electricity in the evening. A solar system without a power storage system will be sufficient for you.
The advantages of solar systems with electricity storage
Independence, self-consumption & feed-in
Of course, such an electricity storage system also has several advantages. Such as independence from the public network. You generate your electricity with the help of your photovoltaic system and store it in your electricity storage system, so you have to draw less electricity from the grid, which also saves you electricity costs.
Of course, this also increases your consumption. Thanks to the stored electricity, you no longer need mains electricity in the evening but can use solar power from your storage at any time.
Your currently unused solar power is not fed into the grid either. Nothing is wasted, and you have the power all to yourself.
In principle, you can, of course, also receive the feed-in tariff with storage. If your storage is full and you don’t need any electricity at the moment, the excess solar power is fed into the public grid, for which you receive a fee.
Environmental friendliness through photovoltaics
Solar power is environmentally friendly and carbon neutral because it is generated from the sun’s energy rather than burning limited resources in coal-fired power plants.
Using a solar storage system increases your consumption, so you need less electricity from the public grid. As a result, electricity production from coal-fired power plants decreases, and less CO2 is emitted.
However, you should also be aware that the production of the plant and storage also releases CO2, and storage contains the limited raw material cobalt.
However, this should be compensated by the long electricity storage and recycling service life.
Long service life & cost compensation
Another benefit that can be gained from a storage system is cost balancing. Electricity storage devices have a long life expectancy of around 20 years.
Solar power alone is free, so you only have to bear the high initial costs. With a solar storage system, there are also no ongoing electricity costs since you do not need electricity from the public grid.
Instead, you can save money and pay off the acquisition costs of the PV system with storage after a few years. This means the electricity will be completely free for you after a few years.
In addition, certain funding measures are offered by the various federal states.
The subsidies are always exhausted quickly, but as an alternative, some banks offer special solar loans to help you finance your solar system with storage.
Which power storage is the right one for me?
When deciding whether you should buy an electricity storage system, you have to weigh the advantages and disadvantages and assess your initial situation.
A power storage device makes sense if you also look for the right system. Consider the following factors before purchasing to save costs and benefit from storage.
Type of battery
For storage systems, different types of batteries can be chosen. All of them have their advantages and disadvantages. The best and most useful are rechargeable LiFePO4 batteries that are effective and durable. The higher costs can be offset over time with long service life. You don’t benefit for long from cheap but less effective batteries.
- Lead-acid batteries are inexpensive but less effective and have a shorter lifespan than their alternatives. They also contain toxic materials that pose a fire hazard.
- Lithium ion solar battery is the most commonly used for solar storage. These are very effective and durable, with efficiencies of up to 95%. However, they are correspondingly more expensive and contain the limited raw material cobalt. They also pose a fire hazard, albeit rarely.
- Sodium-ion battery storage is an even more recent invention. They are inexpensive but durable and are no less effective than lithium-ion batteries. In addition, they are made of common materials and contain no toxic substances. There is also no risk of fire. However, these energy storage devices require much more space than the alternatives.
Size of memory
To enjoy electricity storage’s advantages, you have to choose the right size/capacity. To do this, your energy consumption must be calculated beforehand.
If the storage is too large, a lot of expensive capacity remains unused. If the storage is too small, less solar power can be provided accordingly, and you will remain dependent on grid power.
AC or DC coupling?
The connection between the solar system and the storage tank is also crucial. There are two different options here:
AC coupling: Connection of the storage after the inverter
Since the storage is connected after the inverter in AC coupling, there is a frequent conversion of electricity, which can result in some losses.
The solar energy arrives as direct current from the panels at the inverter, converted into usable alternating current. However, if the electricity is not needed, it must now be converted back into direct current by the battery inverter to be able to store it in the battery.
If the electricity is to be used later, it is first converted back into an alternating current.
The advantage here, however, is the independence of the power storage from the rest of the solar system. Retrofitting or replacing a defective memory is, therefore, very easy.
DC coupling: Connection of the storage before the inverter
If the storage system is DC-coupled to the solar system, the direct current transmitted by the modules can be stored directly in the battery and does not require further conversion.
If the solar power is now to be used, it flows from the storage via the inverter, which converts it into alternating current for use.
There are no energy losses here, but the storage is not independent and directly connected to the system, so the components must all be coordinated.
This variant is more suitable for the new purchase of solar systems with an integrated storage system since the costs are lower than for a later retrofit.
When is an electricity storage system worth it?
A power storage system is particularly worthwhile if a lot of electricity is required in the house and energy is consumed since self-consumption increases significantly with a power storage system.
If you work all day, put your feet up in front of the TV in the evening, and charge your iPhone, etc., then a small storage unit for your solar system is definitely worth it.
Because in the evening and at night no electricity can be generated due to the absence of the sun. Solar power would therefore be completely wasted without a storage system.
However, suppose you work from home and have arranged your daily routine so that you hardly need electricity at night. In that case, a solar system is sufficient even without storage since you draw most of the electricity directly during the day. Your solar system must, of course, be big enough for this.
Retrofitting is usually not worthwhile at the moment compared to a memory-integrated new purchase since the acquisition costs are much higher.
Conclusion: PV system with or without storage?
You have to judge whether a solar system with storage is worthwhile for you. For most people who are usually out of the house during the day, such an electricity storage system makes a lot of sense as long as the costs can be offset over the next few years.
This is because solar power can be generated daily, stored, and used later. So it partly depends on your power needs and what times you need it.
