Energy surplus - what now?

There is no such thing as too much energy. Energy generation can be throttled or the energy can be used for other purposes.

Energy surplus - what now?
Can too much energy hurt? Maybe.

The (too) simple answer is: Yes, too much energy can be harmful. Too much energy could overload batteries and damage them. Too much energy in the power grid can lead to overvoltage and high frequencies. Therefore, measures are needed to keep an excess of energy in check.


This can be done very easily by throttling the power. Of course, all inverters and solar charge controllers we use can throttle their power if the energy supply exceeds demand (batteries full, consumption in the house lower than generation). The question is - do you want to "leave" the energy through throttling?

Here are two things to note:

First, think back to the time when your roof/fence/facade was still free of PV modules. The energy you have "left behind" was about 200 kWh per year per square meter. So if you lose 50 kWh per year per square meter through throttling, that's still progress.

Secondly, the cost of a self-generated kWh of solar power for direct consumption (PV -> Inverter -> Consumption, i.e. without going through a battery) is about 8 cents. The current feed-in tariff in Germany is 8.20 cents/kWh (as of December 2022). So even if you were to feed in, the "profit" would be irrelevant. On the contrary, throttling the system also increases the lifespan of the components - especially the inverter/chargers. Opposite this is a missed "profit" of 10 cents per m² and year. With a generous PV area of 100m², that's 10€/year. For those who need it...

The concern often expressed by customers that PV modules could be damaged without energy output in strong sunlight is completely unfounded.

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Compared to earlier generations, we are surrounded by many electrical consumers today. While the washing machine and fridge used to be the norm, today it's also the clothes dryer, freezer and dishwasher.

On the one hand, such devices relieve us (send someone from your family weekly to the stream to wash laundry), on the other hand we also feel a certain dependency. And then there is also a question of operating costs, especially energy costs. The energy needs of a clothes dryer are not insignificant, despite an efficient heat pump - you could hang the laundry in the sun after all.

Only the clothes dryer works even when it's raining - a question of comfort. Of course, you can also wash dishes by hand and even if we leave questions like the efficiency of water usage aside - you might be able to use your time better than washing and drying dishes.

Is that the end of the road? For our grandparents, the sense of emerging dryers, dishwashers, microwaves, etc. may not have been clear, but for a large part of us, such appliances have become the norm.

What is your standard? Is an AirDresser, a steam cleaner, an air conditioner, a KWL or water treatment pointless? What about a lyophilizer? Oh, you don't know what that is? ;-) These statements are intended to help you realize the difference that an energy surplus can make in your life (comfort and opportunities).

It's not easy for many people to make this mental leap. After all, until now - without your own power plant - you were used to considering energy as a costly and rare good that should be used sparingly.

An air conditioner often has a high energy demand - especially in summer. Assuming you are sitting in a home office at 30°C, wouldn't cooling at almost no energy cost be welcome? Maybe your productivity and personal well-being are higher at 25°C.

Wouldn't it be great to be able to "sink" your energy surplus in the battery of an electric car as well? You would have mobility at almost no cost.

You could also simply "sink" your energy surplus in the hot water boiler. If the alternative is a gas heater, this is definitely the better choice, otherwise you can of course use your heat pump for this.

And what about cryptocurrencies? Terrible energy hogs - right? Well, not all of them and from a purely financial perspective, it's also a kind of battery: you could mine cryptos in the summer and sell them in the winter. ;-)

These are just examples and your individual situation may differ. It is important to realize that some things in life can change categorically if you have surplus energy almost for free. The biggest mistake you can make is simply to extrapolate the current situation (where you are still, for example, on the drip of the power provider).