Inverters must meet new requirements
A few years ago, new European regulations were introduced regarding all power generation units that feed electricity into the grid. These 'Requirements for Generators,' abbreviated as RfG, have applied ever since to all new installations that produce and feed electricity into the electricity network, from large offshore wind farms and nuclear power plants to modest solar panel systems on homes. The new rules aim to make the electricity grid more robust and fair by setting technical requirements that everyone must follow.
Power generation units are categorized under the new rules into different types, labeled A, B, C, and D. Installations with a maximum capacity of up to 1 MW (Mega-Watt, 1 MW = 1,000 kW) all fall under type A; your own home solar system is included in this category. The other types are much larger.
Transition period of two years now over
When the new rules were introduced two years ago, it was decided to first certify and control the large generation units falling under categories B, C, and D. For type A installations, no system had been set up yet, so installers and owners weren’t asked for anything. It was agreed that this transition period would last two years.
Now the time has come: anyone who wants to connect a new solar power installation to the grid must prove that it meets the new requirements. It’s not complicated: the only thing that needs to happen is that when registering on 'energieleveren.nl,' not only the size of the system (in kilowatts, kW) must be entered, but also the brand and model of the inverter.
A type A power generation unit according to the 'Requirements for Generators'
List of approved inverters
As long as the type of inverter is one that is approved, everything is in order. The umbrella organizations of network operators (Netbeheer Nederland) have created a list of all brands and models of inverters that meet the new requirements. You can download the list (28 pages long!) here. Naturally, all inverters installed by Zonnefabriek, from SMA and SolarEdge, including those for solar panels and batteries, are on the list. This mandatory registration only applies to new installations; for existing Zonnefabriek systems, from 12 years ago until now, no action is required.
Nice, such a new bureaucratic step, but what’s the benefit? Well, the goal behind the new requirements is to make the grid more stable. With more decentralized power generation entering the grid, network operators must continue to ensure that the voltage and frequency remain reasonably constant. Fortunately, solar power systems can play a constructive role here: they often bring more stability to the system.
Solar panels ensure balance
How do they do that? Well, an example is the frequency. Throughout the Netherlands, the frequency on the alternating current grid is about 50 Hertz; in fact, almost all of continental Europe is connected in one large 'synchronous' area where the frequency is kept at the same level. The frequency is not always entirely stable; when more power is produced than is consumed at the moment, the frequency rises slightly (to, for example, 50.1 Hz), and conversely, when more is consumed than generated, the frequency drops slightly. In the past, inverters for solar panels were set in such a way that when a certain threshold was reached, for example 50.2 Hz, they would automatically disconnect from the grid to prevent overload. But if all solar panel systems in Europe were to disconnect from the grid at once, it could cause a serious jolt to the electricity grid. And yet, inverters are capable of much more; they can gradually adjust their power output to meet demand. That's why, thanks to the new rules, when the frequency starts to rise too high, all inverters in Europe gradually reduce their power input, allowing the grid to calmly regain balance.
Providing reactive power is another way inverters can help restore balance, but more locally. In Germany, this feature is used to reduce issues of high grid voltage. We also see such issues (temporarily) arising here, especially in the spring; perhaps in the future, our network operators will use the different capabilities of inverters in a smarter way. In this way, solar power installations, thanks to their inverters, help make the electricity grid more stable, rather than less. And with that, we create even more room for clean, renewable energy!
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