In September 2019, for example, a disruption in Dortmund, Germany paralyzed around 900 households. That same month, when power failed in Hameln, more than 19,000 households in Graz, Austria, were affected. In addition, a completely different and new danger is emerging as electricity providers are recording significantly more malicious computer attacks on public power grids in recent years. Against the background of the constant conversions around the transformation of the German power grid toward renewable energies, it must be noted that green electricity cannot always be available in such large volumes. Wind strength, river depth and sunlight are all subject to change, the effects of climate change only creating even greater variations, and these fluctuations in energy production can lead to large shifts in energy levels throughout the grid.
Energy autonomy: becoming a sustainable producer of electricity
Securing your own personal power supply can be achieved relatively easily with the installation of a private photovoltaic-battery system – where homeowners can “tank up” on free electricity directly from the sun. However, there is a risk of low yield in Germany, possibly too small to cover one’s own electricity needs, due to the region experiencing less sunny spells and real energy autonomy only achievable if electricity is also available during the night. Upgrading the photovoltaic-battery system with an energy storage device, for example a back-up-capable RESU battery product from LG Chem, is the perfect solution. While the device takes over the energy supply seamlessly, a reliable inverter provides energy management and sufficient battery charging via PV modules.
By installing a photovoltaic-battery system, the homeowner becomes a power generator, so to speak. Many people decide to install such a system for two reasons: First, generating electricity from solar energy is a very sustainable and ecologically friendly way to reduce your own carbon footprint and produce ecologically valuable electricity. The second argument is to achieve autonomy and independence with their own at-home power supply. With sufficient storage of the self-generated electricity, power outages are much easier to cope with. In this case, critical household appliances, like a fully loaded refrigerator or freezer, can continue to operate reliably even in the event of power failure, which eliminates the risk of essential and sometimes expensive food going bad at no fault of one’s own.
The modular RESU system
The battery used to store energy consists of two battery components and a “Battery Protection Unit” (BPU) responsible for protecting the storage system’s components. The great advantage of the modular RESU’s design is that in the event of damage, only one component needs to be replaced rather than the entire power storage unit. Experience shows that battery components last even longer than electronic ones. Since RESU10M requires very little space and, weighing less than 80 kilograms, can be placed on any load-bearing floor or wall, the space argument is non-existent – the battery easily accommodated in pretty much any home’s cellar or technical room.
Battery storage units provide vital power when public power grids fail, but only when stored electricity has reached a minimum charge level. This is the inverter’s responsibility, which takes on energy management within the house so it can switch the building’s power supply from the public grid to the RESU battery as soon as a power failure is recognized. Which inverter manufacturer is used depends on the type of battery storage. For LV type RESU batteries providing 48 volts, inverters from Solaredge, SunGrow, Solax, Solix, GoodWe, Ingeteam and Victron can be used, whereas HV RESU batteries supplying 400 volts typically use inverters from Solaredge, SMA, Fronius, and Huawei and Delta. This offers 9.3 kWh of usable energy, a capacity of 63 ampere-hours and a nominal voltage of 155 volts with a voltage range between 126 and 176 volts. And thanks to its IP55 housing protection class, the RESU10M can be installed both inside and outside the building. Communication is via CAM2.0B.
Back-up-capable home storage units turn your home into your very own power plant
The first step for upgrading your home to a “private power station” involves seeking the help of an electrician. Some professionals even specialize in photovoltaic-battery systems, such as Bernhard Konrath from Elektro-Konrath, who confirms peoples’ will for greater security of supply after having many conversations with his homeowner clients. “Many of our customers desire to become more self-sufficient, partly to ensure their own secure supply, but also because they want that new feeling of independence from their electricity provider,” explains Konrath. “In principle, photovoltaics is advancing, but of course you only really become self-sufficient if you’re able to store the energy you generate, which is only attainable with a battery like the ones of the RESU line by LG Chem.”
Once the photovoltaic system is installed on the homeowner’s roof, a suitable and reliable combination of a home energy storage (battery) and an inverter is next on the list. Important factors to consider include an energy storage system providing sufficient capacity in kilowatt hours, and a knowing of the building’s expected average energy consumption so an inverter with equivalent output power can be sought out. In addition, the cumulative energy demand at night must be coordinated with the partially charged battery, and it is equally important to determine which devices and appliances should be prioritized in the event of a power outage. Ideally, the output of the photovoltaic module system should be calculated with cloudy winter days accounted for, to make sure enough energy is there to go around.
Independent, free, and sustainable – The vision of an autonomous energy supply
In times of energy turnaround and growing economic uncertainties, homeowners should be taking a greater interest in decentralized power generation. Photovoltaic-battery systems can be installed with suitable backup-compatible storage/inverter combinations in such a way that the vision of an independent and environmentally friendly autonomous energy supply can be realized, even with specific bottleneck situations.