Photovoltaic storage as the key to the energy transition
The energy transition urgently requires a solution to the problem of electricity storage. This is because the production of solar and wind energy fluctuates greatly. Fortunately, there are already various ways of storing surplus electricity. These range from pumped storage plants and fuel cells to lithium-nickel-manganese-cobalt batteries, lithium-iron-phosphate storage systems, saltwater batteries and many more. Nevertheless, the current storage capacity is not sufficient to supply us with electricity without nuclear power and coal in the long term and to keep the power grid stable. Drastic progress must therefore be made in this area in the coming years.
Focus on electricity storage
Photovoltaics and electricity storage - why battery storage is in focus
Mention of electricity storage systems in connection with photovoltaics usually refers to battery storage systems, while redox flow storage systems are rarely used and are mainly used in research. Battery storage systems based on lithium-ion and lead-ion have proven to be the most suitable for use as home storage systems. On a larger scale, these battery storage systems are also used in trade and industry or to stabilize the local power grid.
The storage system for tomorrow's solar power.
Photovoltaic systems that are operated without storage produce solar power that must be used immediately. However, this is not particularly effective as the electricity is mainly generated during the day, when the electricity demand of most households is low. In order to be able to use solar power that is not required during the day when it is really needed, it is advisable to use a storage system.
By using a memory, you can save without changing your habits:
- sustainably reduce your electricity bill,
- make a personal contribution to the energy transition,
- optimize your own consumption and
- Increase your independence from the energy supplier.
- For operators of private photovoltaic systems, it is now cheaper to consume the solar power they generate themselves than to feed it into the public grid and receive a feed-in tariff. The feed-in tariff has been lower than the electricity price since 2011 and now accounts for less than a third of the cost of grid electricity. This fact has led to an increase in demand for battery storage in particular.
Effective use of solar storage tanks
Why more and more people are turning to photovoltaic home storage systems
In recent years, the demand for private electricity storage systems has increased significantly and the installation figures speak for themselves. EuPD Research, a leading market research institute, reports 78,500 new photovoltaic home storage systems in 2019 - almost twice as many as just two years previously. The market continues to boom, with 46,000 new installations in the first half of 2020 alone. There are many reasons for this, but the desire for lower electricity bills and independence are the main driving factors. In addition, the cost of higher storage capacities is falling, which is further boosting demand. In view of these developments, it is now more urgent than ever to find out about the benefits and possibilities of private electricity storage systems.
Electricity storage - the solution for self-produced solar power
The purpose of electricity storage systems is clear: they ensure that self-generated solar power is available exactly when it is needed - usually during the evening and night hours. The principle behind this is as follows:
First of all, the electricity generated in a photovoltaic system is used for self-consumption. This means that active electricity consumers such as running industrial systems, refrigerators or other household appliances are powered by this electricity. However, if more energy is generated than necessary, the surplus solar power is fed into the battery of the storage system and this is charged.
If more electricity is required in the evening or at night, the stored solar power is available. If the demand for electricity during the day is higher than the amount of solar power produced by the photovoltaic system, the stored electricity is also used - regardless of whether the storage system is fully or only partially charged. Only when the stored solar power is no longer sufficient is additional electricity drawn from the grid by the energy supplier.
In this way, a large proportion of the electricity required can be covered by the solar power generated by the photovoltaic system.
Storage accumulators
Optimum operation of an electricity storage system thanks to a professional battery management system
It is generally known that storage batteries consist of a large number of interconnected cells and not a single cell. However, to ensure trouble-free operation of the storage system, a battery management system (BMS) is required which monitors the individual cells and ensures a balanced charging capacity. The BMS switches off the storage system if individual battery cells overheat. It also regulates the charging strategy of the storage system to ensure optimum charging and discharging as well as efficient power distribution.
Find the optimum size for your solar power storage system
If you want to buy an electricity storage system and operate it with your solar power plant, the key question is its size and capacity. It is important that the storage system is large enough to store your self-generated electricity, but not too large, as any additional storage space costs extra money. The optimal size of the electricity storage system should be adapted to your individual needs.
There is an important difference between a high level of self-consumption and a high level of self-sufficiency. If you want to use as much of your self-generated solar power as possible yourself, a high level of self-consumption is important. However, if you want to be more independent from the grid, you need a high degree of self-sufficiency.
In order to be able to use the electricity storage system sensibly, sufficient surplus must be produced by the solar system to charge the storage system. Without a storage system, the proportion of self-consumption is typically 25 to 30 %. This means that 70 to 75 % of the energy generated can be stored. With a small 10 kWp system, you can store approx. 7,000 kWh per year or approx. 20 kWh per day. Please note, however, that solar yields are lower in winter than in summer.
Independence through solar power: why sufficient energy storage is essential
Sufficient battery capacity plays a decisive role in the efficient operation of battery storage systems in combination with solar systems in a commercial and industrial context. Take, for example, a PV system with an installed capacity of 15 MWp. With an average daily production of 60 MWh, the battery capacity can be dimensioned to 32 MWh based on a target self-sufficiency level of 80% and an average daily energy demand of 40 MWh. With such a battery capacity, the company can maximize its self-consumption, reduce the purchase of expensive grid electricity and potentially generate additional revenue by participating in the balancing energy market. However, the economic benefits and optimal battery capacity may depend on other factors, such as local electricity prices and the company's individual requirements. A thorough analysis by experts is therefore recommended to find the optimal solution in a commercial or industrial context.
There is a challenge in the integration of DC-integrated solar storage systems on the market. These cannot simply be integrated into existing systems, as technical changes are often necessary, such as replacing the inverter. This must be large enough to support both the PV system and the electricity storage system. In contrast, AC-side integration does not require such a replacement.
Although there is a wide range of energy storage systems on the market, not all of them are suitable for every use. Some have a high weight and enormous dimensions, which makes them difficult to accommodate and leads to a great deal of installation work. It usually takes several installers at least one day. It is therefore important to choose an electricity storage system that meets the needs and limitations of the business in question.
Maximum efficiency for your PV system: why a storage system is essential
It is extremely important that the device is installed between the PV system and the inverter in order to store the system's direct current directly. Only when required is this converted into the required alternating current and fed into the domestic power grid. In this way, the loss during conversion is minimized and the overall efficiency during charging and discharging is significantly increased. However, it should be noted that the storage system must be adapted to the output of the system, which is why it tends to be more suitable for new systems. In addition, the power of the PV inverter limits both the system and the storage system, as it has to operate both sides. The manufacturer also has to certify a large number of inverter-solar storage combinations, which incurs additional costs and affects the price.
What is important for optimal electricity storage
It is extremely important that the battery storage system is only integrated after the inverter, as it has to convert the alternating current into direct current using an internal inverter before storage. However, this can slightly reduce the efficiency of these devices. Nevertheless, the AC-side integration of storage systems offers a major advantage in terms of flexibility. Regardless of the output of the PV system and the PV inverter, they enable any storage capacity and are therefore particularly interesting for retrofitting existing systems. In addition, AC storage systems can also easily store grid electricity, which can be an advantage when very favorable tariffs are available.
However, it is essential to be extremely careful when installing a PV storage system. Any installation should be carried out by a certified professional to ensure a smooth installation and optimal operation of the storage system.
Increase your independence with an electricity storage system for your photovoltaic system
When purchasing a new photovoltaic system, it is crucial to consider the possibility of investing in an electricity storage system, especially if you are looking for independence. With such a storage system, you have the opportunity to use the majority of the electricity generated by your system yourself and thus increase your self-consumption. This leads to a significant reduction in electricity purchases from the energy supplier.
For systems that were commissioned after 2011, retrofitting with an electricity storage system is almost always of interest. This is due to the fact that the price of electricity is now higher than the feed-in tariff, which means that feeding solar-generated electricity into the public grid does not make economic sense. In the case of earlier commissioning, however, an individual assessment should be carried out to decide whether an investment in an electricity storage system is worthwhile.
Operators of systems that received an extra payment for the self-consumption of solar-generated electricity between 2009 and 2011 should also consider expanding their system with a battery storage system.
Optimize your own consumption with solar power
It is high time to think about energy costs. A kilowatt hour of electricity from the public grid currently costs almost 35 cents. In comparison, self-produced solar power costs only 4-10 cents per kilowatt hour, depending on the type of system. These costs are made up of the expenses for the solar system and the yield over the entire service life. The enormous price difference of up to €0.25 per kWh makes it extremely profitable to store surplus solar power and consume it yourself at a later date. Optimizing self-consumption in this way is therefore highly recommended.
In addition to this financial incentive, other factors should also be taken into account when deciding on a storage system. The future of energy demand will change in the course of so-called sector coupling, which will lead to an increase in electricity demand. The output of private photovoltaic systems is already increasing, as heating, cooling and mobility are also becoming increasingly electrified. For this reason, storing surplus solar power is becoming increasingly important.
It is already foreseeable that a low EEG feed-in tariff will mean that a solar system will generate less and less profit through feed-in. It therefore makes sense to retrofit a PV storage system in order to increase self-consumption and thus benefit from the advantages of renewable energies. Act now and make yourself independent of the high electricity prices!
Important factors when choosing a photovoltaic storage system: capacity, battery type and installed components - what you should look out for
It is very important to take a close look at the technical data and key figures of electricity storage systems and weigh up which aspects are important to you, as the price depends on various factors. These include the storage capacity, the battery type (lithium-ion or lead) and the components installed.
Due to the enormous price range, it is very important to narrow down the list of suitable photovoltaic storage systems based on this information and then compare the costs.
Everything you need to know before buying a battery storage system
It is extremely important that you obtain comprehensive information about the available funding options before purchasing an electricity storage system. There are currently numerous funding programs from federal states and local authorities that you can take advantage of.
In the past, the purchase of a battery storage system was supported by the state KfW funding program "Renewable Energies - Storage (275)". Unfortunately, this program was discontinued on 31.12.2018.
Nevertheless, as a potential buyer, you have the opportunity to obtain financial support for the purchase of a photovoltaic storage system via the KfW funding programs "Renewable Energies" (270) and "Energy-efficient Construction" (153).
Optimize your solar system with a PV storage system - sustainable savings guaranteed
It is highly recommended that you purchase a photovoltaic battery storage system so that you can always use the electricity generated by your solar system when it is needed most. This will reduce your electricity bill in the long term. Thanks to their sophisticated technology, long service life and affordable prices, PV storage systems are an extremely attractive option for both new and existing solar systems. If you have any questions about this topic or our electricity storage system, please do not hesitate to contact us. We will be happy to help you.
Lead or lithium? The advantages of the lithium-ion battery.
The choice between a lead-acid or lithium-ion battery is a key factor when deciding on a solar storage system for private use. In the past, lead-acid and lead-gel batteries were widely used, especially as car batteries. Nowadays, however, lithium-ion batteries are becoming increasingly popular due to their clear advantages over lead batteries:
- The service life of lithium-ion batteries is around 15 years, while lead batteries only last between 5 and a maximum of 10 years.
- Lithium-ion batteries can be discharged up to 100 %, whereas lead batteries can generally only be discharged up to 50 %, as a deeper discharge has a negative impact on the operating time.
- The system efficiency of lithium-ion batteries is over 90 %, while only around 70 % is possible with lead batteries. Photovoltaic systems with lead batteries therefore have to be larger, which causes unnecessary additional costs.