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Expanding photovoltaics: what you need to know

If a household’s electricity demand increases, the photovoltaic system should grow. Fortunately, existing systems can be extended without any problems. But what about the conditions for doing so? Is the roof big enough? Do other components have to be replaced? What about the reward? Our article on PV system scaling sheds light on these and other issues.

In many cases, extending a photovoltaic system is a good idea. After all, their correct size plays a decisive role in cost-effectiveness. Plant operators have several options:

Install additional solar panels on the roof

The connection is established, all components are set up, and everything works fine. Simply increasing the number of bifacial solar panels on the roof looks like the easiest scaling solution. New components just need to be compatible with previously used ones, right? Almost right: Compatibility is enough, but identical modules are better. And: the effort is only worth it if there is still plenty of unused space and the site is at least in good condition. Adequate load-bearing capacity of the roof is equally important. Planning for the system’s expansion can only begin when a load of 30 kg per square meter can be accommodated.

System Expansion Using House Facades

If the roof doesn’t have enough room to move, there’s no reason to give up. Flat modules that attach to the walls of a home are a modern and sometimes aesthetically pleasing option. The biggest disadvantage of facade modules: Typically, the yield is only 70% to 80% compared to optimally aligned roof systems. Among other things, this is due to the properties of the area choking off shade providers such as neighboring houses, shrubs, and trees. If the house is freestanding, power generation can sometimes be optimal—at least if the vertically mounted modules can catch the low summer light. Another advantage of a facade system is that it is easier and cheaper to install than on a roof.

Other attractive solutions

  • Outbuildings: Whether pitched or flat: the space above garages and carports is often unused. Unfortunately, it is ideal for generating electricity from solar charging stations. However, static requirements often require new construction.
  • Solar Fence: Same as the Facade Module for all vertical surfaces. As far as fences go, this also means: the higher the sun, the better.
  • Mini Solar System: You can see them in front of your windows, on your balcony, and the walls of your house. Up to 300 kWh of electricity per year can be independently generated using inexpensive plug-in solar equipment. It’s interesting. No wonder the mini is becoming more and more popular.
  • Solar system in the garden: Comfortable even in the garden shed. However, there would be no refrigerators, water heaters, and televisions without electricity. An island system must not be connected to a public power source.

Building blocks are not everything

Therefore, extending an existing PV system is worth considering. However, simply adding modules is not the only investment. You must also look at other components. The cost of new solar cables is still manageable. But is new equipment also required?

Our article on inverter technology explains the importance of using the right inverter: depending on its input voltage range. The inverter does not generate electricity if the voltage exceeds the lower limit. It may be damaged if it is too high—the more modules connected in series, the greater the specified range. For example, If ten modules with a nominal voltage of 35.2 volts are installed on the roof, the maximum input voltage is 352 volts. An inverter with an upper voltage range of 380-400 volts is usually used. If you add three identical modules, the maximum input voltage can climb to 458 volts – too much for the existing inverter. Whether a larger or a second inverter needs to be installed depends on where the expansion is planned. Projection makes the most sense to discuss in detail with a solar technician or similarly qualified specialist. If you have camping needs, you buy a professional RV power inverter.

Large system capacity and battery storage

If money is no object, operators of photovoltaic systems can provide themselves with the required energy completely independent of the grid. The system just needs to be large enough to generate enough power for storage. If the deep cycle battery storage expands simultaneously with the system, there is no problem.

Most of the time, however, money does play a role. Then retrofitting the energy storage system can also replace adding solar modules. The electricity generated is stored and used when the sun is not shining and the system is not generating income. With batteries, self-consumption can be significantly increased, and electricity purchases from network operators can be reduced accordingly. The purchase is not without cost but will pay for itself sooner or later, just like a photovoltaic system.

Optimize existing systems

Sometimes a photovoltaic system has been in operation for many years, but its performance has deteriorated significantly. If power consumption hasn’t changed much over the years, you might be able to enjoy it again without expanding your system. First of all, professional companies should check the performance of each module. Some may be defective and can simply be replaced with new ones.

Do not replace functional modules at will. The Renewable Energy Act prevents this because the system’s performance may change. Another way is to register the better-performing panel as a new factory. Whether this is worthwhile must be decided on a case-by-case basis.

In conclusion

Life can’t always be planned. Maybe now there is an electric car in the garage, which increases the need for electricity. Or the family has grown, and more consumers now live in the house. If an existing system is to be extended (to be installed on the same property) less than 12 months after commissioning, there are good reasons to do so. The extra yield can be significant. Indeed, even with the addition of a power storage system, it will struggle to double or even triple energy usage. The extra cost has raised questions about whether the bottom line is black or red. In terms of grid operator independence and energy transition, however, the expansion of photovoltaic systems is certainly a gain.

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