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I don't understand what solar autarky means. And what about self-consumption?

Solar autarky means energy independence thanks to the sun and batteries, i.e. independence from the electrical grid and protection against power cuts.

Self-consumption is the ratio between what is produced by the solar panels and what is consumed directly. This indicator gives an idea of where solar energy is going.

We can therefore have a high level of self-consumption but a very low level of autarky, and therefore a very low level of energy independence.


The solar installation will consist of a solar roof, a hybrid inverter that can operate independently of the electricity grid and a battery.


The advantages of this innovative type of solar installation are :

  • Energy independence (autarkiy rate) of up to 85% for a villa with a heat pump and an electric car.
  • Safety in the event of power blackouts. The system will continue to work with the sun and batteries, which is not the case with a standard solar installation.
  • Financial insurance against rising energy prices
  • Flexibility of use compared with a standard solar installation, as energy can be stored and/or used in the evening.
  • Have a solar-powered ” fuel pump ” in your garage, so you can fill up your electric car in the evening.

What are the limits of a conventional installation without batteries and intelligent inverters?

The yellow curve represents solar electricity production, while the blue curve represents household consumption. Energy is produced at the time of day when demand is lowest. As this surplus cannot be stored, it is resold at a low price to your supplier. In the evening and at night, you consume energy from the grid.


This solution does not offer energy security in the event of a power blackout, or financial security in the event of a rise in electricity prices.


Batteries allow excess energy to be stored rather than sold. As a result, you can use solar energy even in the evening and at night.


A conventional system offers 20 – 30% independence. 70 to 80% of what you produce will be fed into the grid and sold back for around 1/3 of the purchase price. In the event of a power cut, the system must shut down.

What are the advantages of an autarkic solar system?

An intelligent autarkic installation with battery storage conserves unused energy and offers greater flexibility of use (green on the graph). In the event of a power cut, the system continues to operate automatically by switching to ” hut mode”.


A 85% autarky rate is easily possible. This means that 85% of your annual power consumption comes from the sun!


The system is smart and works by priority. The solar energy will be used during the day to power the house and fill the batteries. The energy is sold back to the grid only when the batteries are full. The energy stored in the batteries can be used to power the house at night or in bad weather. If the batteries are empty, the system will automatically source energy from the grid.

What's the installation budget?

The budget is around twice the cost of a traditional solar installation. A single-family home costs between CHF 60,000 and CHF 80,000, depending on the amount of storage required.


This higher investment is justified by the system’s components:

  • The inverter is Studer Innotec’s next3.
    • This is a smart 16kW inverter with 2 MPPT solar inputs of 8 + 8kW. It allows you to give priority to one or other option for the energy produced by the PV panels (store, use, sell).
    • Development, manufacturing, assembly and quality testing are all done in Switzerland (Sion).
    • So you can be sure that your supplier will be close by in the event of a problem.
  • You need to invest in batteries.

How profitable is my installation?

It varies according to electricity use and future costs.


With current prices and consumption averages, we believe that a 10-year payback period is possible for the following reasons:

  • 85% autarky means that 85% of your total annual electricity consumption will actually come from solar energy. Your power bill will be close to CHF 0 with this system.
  • Savings on power and fuel => solar mobility rather than electric or thermal mobility.
  • With energy prices increasing, your power bill will remain close to CHF 0 even if prices rise.


Consuming free energy at home is therefore possible from the moment of amortization.

Is it possible to convert an existing installation to autarkic solar power?

Yes, but you’ll need to add or replace your existing inverter and add batteries.

How long can my house last in the event of a power cut?

This will depend on a multitude of parameters and the time of the power cut. In the event of a power cut, the system will continue to work on a priority basis, with the house being supplied with solar energy as a priority. If there are none left, the house will be powered by the battery.


The duration before the battery runs down to zero will therefore depend on the consumption of the house, the solar production and the battery level at the time of the power cut.

However, it is possible to set a minimum battery level to guarantee a reserve in the event of a power cut. It is also possible to manually force the battery to 100%, for example in the event of a predicted power cut.

What type of battery is recommended for this system?

Studer Innotec’s next3 has the advantage of being able to work with all 48Vdc battery technologies.


For residential applications where there is no risk of low temperatures, we recommend LFP-type lithium batteries, which are fairly compact and communicate permanently with the inverter.


What’s more, it’s the safest lithium battery technology in terms of fire protection.

What's the benefit of an electric vehicle?

As well as making a positive contribution to the environment, an electric vehicle will give you a significant financial advantage over a combustion-powered vehicle, especially if you recharge it using energy generated by your own solar system.


By taking into account the savings you make on travel, the profitability of your solar system will be greatly improved.


You can “fill up” your vehicle at home without it costing you anything in the process.

Is it possible to charge my electric vehicle bidirectionally?

The next3 has a flexible input/output designed among other things for this purpose. Few cars are already designed for two-way operation, but the trend seems to be confirmed. Our solutions will continue to evolve in line with market needs.

Will solar production continue in the event of a power cut?

Yes, solar generation works independently of the power grid. This is not the case with standard solar systems, which switch off in the event of a power cut.

Is there a monitoring application and is it a paid service?

Yes, a portal and an application provide a live view of solar production, solar power fed into the grid, the home’s electrical consumption and battery levels. It is also possible to check the history of previous days. This service is free for all next3 owners.

Where does the model and experience of solar autarky come from?

Solar autarky comes from the 30 years of experience of our partner Studer Innotec, a Valais-based manufacturer of power electronics for solar installations in areas without a power grid.


The mountain hut model is the best known in Switzerland. It has no power, but it does have solar panels, an inverter/charger and batteries. During the day, the energy produced by the roof is consumed by the hut, while the surplus is stored in the batteries. In the evening, the batteries are used to continue powering the hut. If the weather is bad for several days in a row, an external back-up power supply (often a diesel generator) is used to secure production.


Residential solar autarky works on this model: you remain connected to the electricity grid, but you use it only as a back-up and no longer as the main source of power.

What is an inverter?

An inverter is an energy converter. The energy produced by a PV panel or battery is “flat” (known as DC energy). The inverter transforms the current into AC, either from the solar panels (ongrid inverter) or from the batteries (offgrid inverter).


The systems offered by smartsuna are produced exclusively by Studer Innotec, which manufactures offgrid inverters. However, the next3 is a hybrid inverter that can be connected simultaneously to PV panels, batteries, consumers and the electricity grid.

What is the guarantee on the equipment supplied?

The next3 comes with a 10-year guarantee. The warranty can be extended for a further 5 years.

How long will the batteries last?

The supplier gives a 10-year guarantee. The technical documentation gives 15 years and 8000 cycles. 1 cycle represents a complete charge/discharge of the battery.


In an autarkic system, we estimate the number of cycles at between 200 and 250 per year. So it’s the years that will determine how long your batteries will last.

What type of building is suitable for solar autarky?

The solar autarky model can be used anywhere: single-family homes, apartment blocks, businesses, factories and more. Of course, the dimensions vary depending on the category of building. Smartsuna can help and advise you on your project.

I'm concerned about the environmental impact of my system. Is solar energy a sustainable source in the long term, particularly in terms of solar panel production, waste management and recycling?

Like all hardware, a solar system involves a certain amount of grey energy. But the advantage of such a system is that it produces 100% renewable energy over a long period (more than 25 years) without producing CO2. As the solar and battery industries become increasingly important, recycling plants are gradually appearing in different parts of the world, to ensure minimal environmental impact.

I saw competing offers on social media. Why is smartsuna different?

There are a number of serious and competent players in Switzerland with whom smartsuna works on a regular basis. What sets smartsuna apart is its extensive experience in battery-powered systems, with an extensive track record in mountain huts and off-grid systems around the world.


Since battery-based systems have only recently been connected to a public electricity grid, it is still rare to find companies with the right expertise in this field. That’s where smartsuna can make a real difference.


The autarky concept offered by smartsuna is unlike anything offered by competitors, who install only solar panels. Beware of systems that also contain batteries and inverters, but which do not particularly offer all the options needed for a system that guarantees maximum autonomy and can supply consumers in the event of grid cuts. The information provided on some Asian products is often misinterpreted by users and installers alike. Don’t hesitate to contact our team to find out more about these differences.

Where should I install my system, bearing in mind the size of the installation and the noise generated?

The smart inverter is the size of a small suitcase, the batteries the size of a washing machine. So you don’t need a huge space to install the system. Traditionally, the inverter is hung on the wall of the technical room. Under full load, the noise level is that of a kitchen fan, but the rest of the time it is virtually silent. Full charge only occurs during the day, when the sun is shining. You won’t have any noise pollution.