Sonnen sales boss: Germany’s solar peak law is ‘revolutionary’

Fermin Bustamante, head of sales and marketing in Germany, Austria, Switzerland at German battery maker Sonnen, tells pv magazine the low-point for home energy storage systems was probably reached in summer 2024. He says the requirements of the Solarspitzen and of section 14a of the EnWG, could signal a change in fortune for home batteries and smart energy systems

pv magazine: What made you switch from [Swedish energy company] Vattenfall to Sonnen?

Fermin Bustamante: I had already worked in the solar industry for a number of years up until 2015 and was responsible for the launch of [Chinese inverter maker] Sungrow in the EMEA [Europe, Middle East, and Africa] region, for example. At some point I wanted to try something new and joined Vattenfall in the e-mobility sector. The main focus was on expanding the charging infrastructure. A lot has happened in the solar industry during this time. In my view, much more than in e-mobility. Photovoltaics, [energy] storage, mobility, and, above all, intelligent energy management are growing together and individual components are becoming a system. I find that extremely exciting because, in my view, that is the last major link for a successful energy transition. We have already come a long way in renewable electricity generation but the whole thing will only be sustainable and cost-efficient if we remove the weather-related random factor and turn it into a constant energy source and that is only possible with intelligent control. Starting at the household level, through energy management, right up to the [electricity] distribution and transmission networks with virtual power plants. It is precisely in these areas that Sonnen has repeatedly stood out to me as a pioneer during my career so the decision [to move] was not difficult for me.

The latest figures from [German trade body] BSW-Solar have shown that demand for photovoltaic home storage systems fell slightly in 2024. This was mainly due to weakening demand for private rooftop systems. How has this affected your business in Germany?

Yes, of course we felt that too and had to accept cutbacks, like many others. The warehouses of many installers were full for a long time, which had a delayed impact on us as a manufacturer. But I think we saw the low point in demand in the summer of last year and we countered this with a whole series of measures. These include new products such as our commercial storage system Flexstack, which immediately won the Smarter E [trade show] Award. The new sonnenBatterie 10 performance+ was even oversold when it was launched in September. So these products got off to a pretty good start. The situation is, of course, not yet comparable to the boom in 2022/23 but our production in the Allgäu [region of Germany] is currently at full capacity and the order situation also means that we have been able to significantly expand our sales team in recent months and thus be able to provide our partners with intensive support.

In Austria there was a similar situation to that in Germany. Did you also see a decline in demand there?

Yes, basically we have seen a similar trend in all European markets as in Germany. Compared to 2023, things went downhill and then we reached the bottom in the summer. That’s why we took very similar steps in Austria. We expanded our sales team and launched a new product, the new sonnenBatterie 10 performance+, which has also been very well received there.

What were total sales in 2024 and what are the goals for this year?

Unfortunately, we cannot give any specific figures but of course our sales in the DACH market declined in 2024. We are quite optimistic about 2025. We were able to carry the momentum from the second half of the year with us and are consistently continuing on our path. This includes, for example, that we will soon be introducing a new product specifically for the DACH market but the political decisions of the last 12 months, such as Section 14a [of the] EnWG or the solar peak package, also offer us and our partners great opportunities. The right course has finally been set so that we can fully exploit our strengths as a system provider with our integrated energy management and the virtual power plant. This means that we are uniquely positioned on the market at the right time, which our partners also confirm.

A parallel is often drawn between solar module and energy storage manufacturers, when it comes to falling prices. How much have the prices for home storage systems fallen in your area over the past year and what measures are you taking to compensate for the price drop?

The prices of modules were a disaster for German photovoltaic manufacturers but a blessing for end customers and the energy transition. Solar power is cheaper than ever. We have not seen this extreme development in the [energy] storage market but of course we have also reduced our prices, which are now very competitive. But it is also clear that we will never be the cheapest provider on the market. There are many batteries on the market that can only charge or discharge and they hardly differ from one another. As a system provider, we can offer added value such as direct marketing, intelligent control, and the [Sonnen] virtual power plant, and thus [we] achieve much higher added value for customers over the service life than is possible with a standard [energy] storage system.

Are customers willing to pay more for it?

Most people are concerned with the price-performance ratio. If I get more, I am also prepared to invest a little more. Price is usually not the only decision criterion. Let’s take a new example, such as [data] security and the [German Federal Office for Information Security agency] BSI’s warning about remote-controlled components from China. As a domestic manufacturer, we have control of our systems in our own hands; our servers are located in Germany. This is becoming increasingly important because the new laws are moving intelligent [energy] storage deeper into our energy system. There will certainly be a discussion about which technologies and providers will be allowed to do this in the future, just as we see in telecommunications. We are already assuming this responsibility, for example by providing system services every day with our virtual power plant. In this way, we offer our customers data security and investment security. This is also a value that is built into our product.

The Solar Peak Energy Act has now finally been passed. Do you expect this to provide a new impetus for storage demand?

The law is revolutionary and, in our view, it was long overdue. The promise of the energy transition is clean and cheap energy. We have achieved this on the production side; solar power is often the cheapest source of energy. But if this cost advantage is lost in the expansion of the electricity grids, we have not gained much. This is also why the energy transition is sometimes perceived by the population as too expensive, and unfortunately, rightly so. This is why this law is so important, just like Section 14a of the Energy Industry Act or the requirement for dynamic tariffs. All of this ensures that it is much more worthwhile for households to distribute solar power intelligently over time and not just dump it into the grid when it is available. The days of full feed-in [of excess solar electricity] are now finally over, as is the classic self-consumption [model], with a simple [energy] storage unit because if the storage unit is full at 10 a.m., in summer, that does not relieve the strain on the grids. What counts now is intelligent [energy] storage with a connection to the energy market. This is undoubtedly a key impulse for the market that will change a lot. In any case, we are ready; system intelligence will finally be rewarded. We have been counting on this for many years, not just since the new law.

Is this change of direction with the new law clear to everyone?

We can at least see that the new law is causing a huge need for information among installers and end customers. The new law raises a lot of questions. There are many details that need to be understood. What are the exact technical and legal requirements? How do I calculate the profitability? When are existing systems affected? Our experts are on hand to offer partners advice and support. With such innovations there is always the risk of doing something wrong and the customer not getting what they want or what would be best.

You said that energy storage alone is no longer enough these days, it’s also about intelligent control and energy management systems. What does Sonnen have to offer in this regard?

Let’s stick with the Solar Peak Act, which practically requires such technologies: As long as a new [solar] system is still in … 60% curtailment at the beginning [as required by the new legislation, regarding export capacity to the grid], we can greatly reduce curtailment losses with our forecast-based charging. The fact that we can do this very well was recently confirmed by the electricity storage inspection at the HTW [Public University of Applied Sciences] Berlin. In addition, there is our energy manager, which, for example, in combination with our sonnenCharger, ensures that surpluses are specifically charged into [an] electric car. When the system then receives a smart meter, which unfortunately can still be quite difficult in Germany at the moment, we bring it into direct marketing and thus onto the energy market. In direct marketing [of energy onto the wholesale market], the 60% handbrake can be released immediately for small systems. The [energy] storage can then, for example, be specifically discharged into the grid via our virtual power plant in summer and achieve a good price on the market there. This means that it is largely empty in the morning so that it can store the midday peak and thus avoid … negative electricity prices. In the future, larger [energy] storage units with higher performance may also be useful here, as negative prices often occur during the hours with the highest photovoltaic yield. Each of these steps requires intelligence, which is already included as standard in each of our storage units.

Do you plan to offer dynamic electricity tariffs to your customers?

Last year we introduced our dynamic tariff EnergyDynamic, which we have been offering since the end of 2024. Here, too, we use the intelligence of our system of local energy management and [our] virtual power plant for our price optimization. If our own generation is not sufficient, charging takes place when prices are at their lowest. With this optimization, our customers can save significantly more than with a simple dynamic tariff that is not controlled. At the same time, we are also continuing to offer our fixed electricity tariff sonnenFlat direkt. Not everyone wants a dynamic tariff, as [although] it can, of course, be cheaper, [it] does not offer the predictable security of a fixed tariff. This means we can offer every customer what they want.

From pv magazine Deutschland.