- Press Release
Intelligence over capacity

Should modern homes be completely energy self-sufficient?

  • More and more buildings in Germany are equipped with solar PV systems.
  • Excessive capacity for PV generation and battery storage is not necessary to maximize self-consumption.
  • Intelligent integration is the key to becoming cost-effectively self-sufficient.

Munich, March 6, 2024 – The number of buildings with their own solar power production is steadily increasing. 2023 brought a new record for solar power installations in Germany and the European Union, a large portion of which was residential solar. But how can homeowners guarantee that their investment pays out in the long run? Experts from gridX and Homenergy explain what is most important when it comes to self-sufficiency.

It's all about the right setup

"Upgrading homes with PV systems and other sustainable energy assets allows everyone to contribute to the energy transition," says Baptiste Feron, Head of Energy Management at gridX, Europe's leading smart energy company. Anyone who produces their own electricity using PV and can store it for later use not only maximizes their self-sufficiency with sustainable electricity, but can also reduce electricity costs and CO2 emissions compared to conventional generation. However, it is important to optimize the setup for each individual use case. "The best and first port of call should always be a no-obligation consultation with a solar installer," says Bastian Busl, Managing Director of Homenergy, an up-and-coming holistic energy renovator based in Munich. Here, experts can easily clarify questions and determine the most suitable solution. As a general rule, equipping four square meters of (roof) surface with solar panels provides one kilowatt peak (kWp) of power. For most single-family homes, a PV output of around 8.5 kWp is a good choice, says Busl. But this can be adjusted to match their exact electricity requirements. Corresponding storage capacity should also be installed: a normal detached house would usually require between five and 15 kWh. Other optional energy assets, such as a heat pump or wallbox and a smart energy management system (EMS), also add value.

More capacity ≠ better protection

gridX expert Feron believes that increasing capacity beyond standard guidelines doesn’t necessarily deliver benefits.  More important are the battery’s maximum charge and discharge rates, or how much solar power the battery can absorb and power it can supply at a given point in time. Overall capacity is less important as a household is very unlikely to be dependent on stored power for long periods of time.Feron explains: "The European energy system is extremely robust. It is highly unrealistic that there will be such a serious and permanent overall failure of the power grid to warrant individual homes becoming completely self-sufficient, aka. using only self-generated solar power and stored energy from household batteries." According to him, there are always generation sources in today's grid that quickly step in as a substitute in emergency situations. If, for example, a power outage occurs, it takes only roughly 12 minutes on average for the substitute power to step in. "As such, there is no reason to dig too deep and choose excessively large capacities to prepare for the worst case scenario. This is simply not foreseeable in today's electricity system," he advises.

Self-sufficiency to become more important in the future

According to Feron, self-sufficiency will likely play a more central role in future energy systems. With the increasing rise of renewable energies in the electricity mix, central power supply could also become less secure. As is already well known, renewable resources such as solar and wind power only generate energy when the environmental conditions are right, i.e. when the sun is shining or the wind is blowing. Busl adds: "The increase in severe weather events and the sharp rise in energy consumption due to the increasing electrification of some sectors, namely heating and mobility, should also not be ignored. As soon as the energy system becomes fully renewable, this could become a challenge for the grid." The Homenergy Managing Director points out that in the long term, it may make sense to increase the degree of self-sufficiency of your home today.

Off-grid self-sufficiency needs more than PV and batteries

However, in order to maximize the degree of self-sufficiency, the setup has to be right." Just because a house can produce its own electricity doesn't mean it will be completely energy self-sufficient in the worst case scenario," says Feron. For a home to be completely self-sufficient, i.e. independent of the electrical grid, more is needed than just PV and storage systems. With an advanced EMS, the utilization of this locally generated or stored electricity can be constantly maximized. Feron underlines that an EMS is a crucial tool for any household that installs decentralized energy resources, such as heat pumps, battery and PV systems: "The EMS intelligently connects these devices and optimizes all energy flows so that local energy supply and demand are perfectly balanced and self-consumption is automatically maximized," the gridX expert says.

Further information on smart home energy management and optimizing self-consumption is available online at: gridx.ai

((Illustration: © gridX GmbH, Reprint free of charge; Image caption))

Energy self-sufficient when the grid fails? According to gridX expert Baptiste Feron, it makes sense to equip a home with sustainable energy systems such as a PV system and battery storage. But intelligence is more important than capacity.

About gridX

gridX is Europe's leading smart energy company based in Aachen and Munich. With its IoT platform XENON, gridX enables manufacturer-independent monitoring and management of distributed energy resources. XENON allows partners to develop and scale energy management solutions faster than ever before. By partnering with gridX, Fastned is able to install more charging points at sites without the need for costly grid extensions, and the Viessmann Group is able to offer its customers intelligent and integrated home energy management systems.

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