Storage of electricity from photovoltaic energy at home

In this article I will tell you everything about the storage of energy from solar panels. what are the different forms of storage.

Storage of electricity from photovoltaic energy at home: forms, profitability and prices

Having a photovoltaic installation next to a single-family home allows you to use a number of different amenities. Investors who decide to install a photovoltaic installation obtain not only independence from the increasing prices of electricity, but also the possibility of  storing the electricity produced at home  .

• What are the most profitable ways to store energy from renewable sources and why should you choose them?
• What options are generally available?
• What Should You Know About Solar Energy Storage Batteries?

We present the answers to these questions and many more in our post. We invite everyone who is interested in the topic of storing electricity from photovoltaic energy to read.

What is photovoltaic energy storage?

Before we move on to identifying ways to store electricity, let’s take a look at the principle of storing it at home.

Solar energy is supplied by a photovoltaic installation to the batteries, where it is stored in the form of a chemical substance. The next step is to convert it into electricity. This, in turn, can be successfully stored in energy reservoirs, which can be recharged after discharge.

It should be added that they are used more when the production of electricity exceeds their consumption.

Forms of electricity storage

Owners of a modern photovoltaic installation can choose from several popular solar energy storage methods.

What are we talking about? 

1. One of them is to  store the excess energy generated in the electricity grid  , which allows you to use the discount system – depending on the size of the installation, we will receive from 0.7 to 0.8 kWh.
2. Another method involves the use of  chemical batteries  (including lithium-ion and lead-acid). In this solution, solar energy is converted into chemical energy. 
3. Storage can also be mechanical,  with the use of compressed air  accumulators  , or thermal  , latent or sensible heat accumulation.
4. We can also use  supercapacitors  for energy storage  . It is a type of electrical storage. With the thermal option, there will be a build-up of sensible or latent heat. 
5. The most common and chosen solution is  energy storage in rechargeable batteries or accumulators  . This electromechanical method of energy conversion is often used in homes. In the case of large solar parks, it is recommended to store solar energy mechanically and chemically. 

Photovoltaic energy can be  on the grid  (connected to the electrical grid),  off the grid  (energy is stored only in batteries) or  mixed  .

Discount system profitability

The discount system is compared to the electricity storage of photovoltaic installations with an annual efficiency of 80% or 70%. The lowest value applies to photovoltaic installations with a power greater than 10 kWp.

With the cooperation of a solar installation with a heat pump, it is possible to increase the proportion of self-consumption to 30-40% and thus also increase the discount factor to the level of 84-88%.

In turn, if the inverter uses its own energy, which it receives from the electricity supplier, then one can speak of a 20-30% loss of energy produced by the photovoltaic installation. 

Batteries for energy storage

To be able to talk about the most economical storage and use of electricity in a photovoltaic installation, it is convenient to consider the effective conversion of the chemical energy contained, for example, into hydrogen. Therefore, the attention of investors and prosumers should be directed towards the storage of electricity in chemical batteries.

According to what criteria should batteries be selected? 

It is certainly worth considering factors such as:

• ability,
• Power density,
• Energy density
• and the number of charge or discharge cycles.

Currently, lithium-ion and lead-acid batteries can mainly be used on the market; both types are available in numerous variants.

Each battery has two cycles of operation:

1. one of them is in charge of   loading  ,
2. the second for   the release of energy  .

Superiority of lithium-ion batteries over lead-acid batteries

Lithium-ion photovoltaic batteries are the preferred option not only because of their rapidly falling prices, but also because of the many benefits that this technology offers.

Lithium-ion warehouses are distinguished above all by the high efficiency of energy storage: it reaches up to 80%. In addition, they also guarantee a much higher density of stored energy, which translates into less weight. In addition, they are also characterized by high power density, which in practice allows low capacity batteries to be charged and discharged using high currents.

This property is extremely important, especially when it comes to an efficient way to store electricity at home. Under such conditions, large but short power consumption will occur more often.

Does lithium-ion technology only have advantages? Like any other, it has limitations, including a rather high price and the need for precise charging. Any disturbance in the charging process or damage to the battery is associated with the possibility of self-ignition.

In order to talk about the highest level of safety in the use of lithium ion batteries, it should be remembered that their use in a photovoltaic installation is based on one of two concepts. The first involves the use of a separate inverter that will only handle the batteries. The second focuses on integrating the operation of batteries and photovoltaic modules through an inverter.

It is worth adding that it is not only lithium-ion technology that is popular today. Batteries in the same family, although made with LiFePO technology  , lithium iron phosphate,  are just as popular  . These batteries are distinguished by their high tolerance to malfunction, their low weight and their extremely high discharge capacity.

Renewable energy storage prices

Currently, the most widely used solar energy storage facilities are lithium-ion batteries. However, when deciding to buy them, it must be borne in mind that the investment cost will be quite high.

Prices for lithium-ion batteries start at around PLN 10,000, and available battery capacities range from around 3 kWh to around 10 kWh. 

What is the lifespan of these batteries? That’s   roughly 10,000 charge cycles, which is roughly 5-8 years of use  . The return on such investment increases when the manufacturer grants a warranty of up to 10 years, and the condition of protection is installation and service performed only by a certified installer.

Benefits of home energy storage

Energy storage at home is especially recommended as a good solution for people who do not consume much energy during its highest production, that is, during the day. Modern photovoltaic energy storage systems will also prove useful in locations exposed to frequent power outages. In addition, it is a solution dedicated to investors who want to use the energy produced by the photovoltaic installation for their own needs.

What are the benefits of using batteries for energy storage? 

• First of all, it should be noted the   maximization of the use of all the energy  produced by photovoltaics.
• It is also important that the owner of a photovoltaic installation is  completely independent of energy  , even when there is no electricity on the grid. A home warehouse allows you to use solar energy where there is no access to the electrical grid and ensures that there are no power outages.
• In addition, owners of photovoltaic installations using batteries can choose the  capacity that best suits their individual needs  . Although the use of domestic energy storage from renewable sources is not common today, with the passage of time and work in the implementation of the most modern technologies, without a doubt it will be possible to speak of a complete success in the decentralization of the energy system. In this case, the use of electricity from the grid will only be an emergency exit.

Profitability of energy storage on farms

The purchase and installation of modern photovoltaic systems that allow the storage of solar energy is a solution also dedicated to  farms  .

In the case of such an investment, the effect of scale is important. Solar cells placed on large surface objects are capable of generating the energy necessary to cover current needs, as well as obtaining its surplus. The profitability of this type of investment raises no objections.

The future of photovoltaic energy storage

The objective of the activity of the European Union is the greatest possible participation of RES in the production of electricity. This means that storage technologies will continue to be improved, which can have a positive effect on battery performance.

It is worth emphasizing that the development of energy storage methods is a key element to improve energy security and the dynamic development of renewable energy; Without this, you cannot talk about the development of renewable energy sources.