Power storage for a family home: Is it worthwhile?
You are covering your electricity supply with a PV system or planning to do so. As a next step, you are considering whether it is worthwhile to install a power storage system for your one-family home? Then you want to know what to consider when buying one? We answer these questions in the following article.
Environment, Independence, Finances and Common Good
The benefits of power storage units can be grouped into four categories: Environment, Independence (of power suppliers), Finances and the Common Good. Let's start with the environment.
Power storage systems are an important component of the energy transition. Away from centralised power plants, towards a decentralised power supply. Away from coal-fired power, towards solar power. Every kilowatt-hour of solar power avoids 0.4 kg of CO2 emissions compared with the same amount of power produced by a lignite-fired power station. With a useful life of 15 to 20 years, installing PV and storage in an average German household can avoid between 100 to 200 tonnes of CO2 emissions created by burning lignite to create power.
Another benefit: A power storage system will transform your home into a small power plant. Power storage systems do not require energy transport over long distances and power lines. They increase the available share of renewable energy and speed up the energy transition.
Most solar power storage unit owners quote being independent as their main reason for the acquisition. More independent of power suppliers, energy price hikes and weather patterns. More independent of electricity suppliers, more independent of energy price increases, and more independent of the weather.
The less electricity you buy from your power supplier, the more self-sufficient you become. The degree of self-sufficiency indicates the percentage of the annual power consumption you can cover with self-generated clean solar power.
Owners of one-family homes equipped with a solar power storage unit are at an advantage. Self-sufficiency degrees of 60 to 80 per cent is realistic. In the winter months, however, a high degree of self-sufficiency is hard to achieve.
You will increase the degree of self-consumption by using more of the self-generated solar power. Utilise your main household appliances when the sun is shining. In practice, this is not always feasible as many people are away from home during the daytime, for example. Alternatively, store the power to have it available at any time. Reducing electricity demand in your home will also increase self-sufficiency.
With a higher degree of self-sufficiency, you will ultimately be more independent of the electricity price developments. Solar power generated by your PV system will always have constant production costs.
Power storage units can secure your home power supply in the event of a power grid failure caused by storms or grid overloads. They will increase your independence from the power grid. With the help of the RCT Power Switch, the RCT Power Storage System will automatically switch to the backup power function. Essential household consumers such as your refrigerator or your WiFi network continue to operate.
As a whole, solar power storage systems reduce your dependency on the weather and the time of day. When the sun is not shining, the solar power storage system supports the energy supply of your one-family home.
It is difficult to provide a sweeping answer to the question of whether buying a solar power storage unit is financially worthwhile. Many individual parameters, some only effective in the future, play a role.
Hence, we only list a few parameters for your consideration. Energy is becoming more expensive. We have seen drastic price rises in recent months. The trajectory is upwards. The average retail electricity prices are around 33 cents per kWh. (as of June 2022)
The price of 1kWh solar power generated by a 10kWp PV system is between 10 to 12 cents. At present, you save an average of 22 cents with every kilowatt-hour of self-generated power electricity. These savings will soon rise to 30 cents, 40 cents or more.
Your power usage patterns are another parameter. How much solar power do you consume? When do you need it? Is it during the day or in the morning and evening hours?
One important parameter is the power storage system itself with its initial cost, its efficiency and long service life. RCT Power's solar power storage systems rely on long-lasting and efficient lithium iron phosphate cells (LiFePo4).
RCT Power's 10kWp system is the most energy-efficient system on the market. It was confirmed in the annual energy storage inspections of the HTW (University of Applied Sciences) Berlin in 2021 and 2022. The more efficient solar power storage units are, the less energy is lost. The bottom line is more savings.
Not many people know that installing a power storage system in a home is an important contribution to the common good of our society. Power storage systems reduce the costs of power grid expansion. The reason for this reduction is that low-voltage grids need to be available on sunny days when PV systems produce excess solar power. The expansion is expensive and the costs are passed on to consumers in the retail electricity prices. A network of grid-serving power storage systems reduces the need to expand the low-voltage grids with a potential of annual savings in the 3-digit million range. As a result, electricity prices will be lower for everyone, including those who cannot invest in renewable energies.
Your family home with a power storage system contributes to a low-cost electricity supply for everyone. It is an invaluable contribution in times of exploding energy prices.
We can also see psychology in action. When many people participate in an activity supporting the common good, they motivate others. They become role models and the drivers of a sustainable energy transition. We are stronger together.
What you should consider when buying a power storage unit for your home?
The previously listed benefits of power storage units have convinced you. Now, you must define the expected performance requirements the units need to fulfil in your home. Consider the following factors: Design, battery technology, and efficiency.
The power storage unit size should match your power consumption pattern. Undersized units reduce the achievable degree of self-sufficiency. Oversized units have a lower economic efficiency. RCT Power's solar power storage units can be selected in modular steps from 3.8 to 11.5 kWh nominal capacity. You can match the unit size to your home and your consumption.
We did already mention one core component of the power storage unit, the battery. RCT Power relies on lithium iron phosphate batteries. They show particular high durability and are environmentally friendly. They have high cycle stability and very high efficiency. They contain no toxic heavy metals and do not use controversial raw materials such as cobalt. Equally important is that the technology is safe, established and backed by reliable scientific research.
Various parameters determine the performance of your power storage unit. One of these parameters is the depth of discharge. It indicates how much of the unit's nominal capacity can be discharged during the charging cycle without negatively impacting the service life. Your power storage unit should ideally have a depth of discharge between 80 and 90 per cent.
Another parameter is efficiency. It describes the losses that occur during energy conversion. Not all of the solar energy that is initially charged to the battery can be used again during discharge. In 2021 and 2022 the Berlin University of Applied Sciences (HTW) found that the most energy-efficient power storage system in their annual Energy Storage Inspection came from RCT Power. The university certified an energy efficiency of 95.1 per cent for the 10kWp system consisting of the RCT Power Power Storage DC 10.0 and the Power Battery 11.5. In the 2020 edition, RCT Power's 5kWp power storage system was already ranked top.
Equipping a one-family home with a solar power storage system
If you need additional information or want to know more about power storage systems we will be happy to advise you on how to make your one-family home more independent from power suppliers and more environmentally friendly.