Solar power system: Is solar power worth it?

7.1.2021
  1. Great potential for solar installations in Switzerland
  2. A solar system is ecologically worthwhile
  3. A solar system is economically worthwhile
  4. Factor 1: The roof
  5. Factor 2: The costs
  6. Factor 3: The subsidies
  7. Factor 4: The tax deductions
  8. Factor 5: The feed-in tariff
  9. Factor 6: Self-consumption
  10. Solar Calculator: Is a solar system worth it for you?

Switzerland consumed more than 57 billion kilowatt hours or 57 terawatt hours of electricity in 2019. According to a recently published study by the Swiss Federal Office of Energy SFOE, we could cover our entire electricity consumption with solar energy alone. The potential of solar installations on roofs (50 terawatt hours) and facades (17 terawatt hours) would be sufficient.

Great potential for solar installations in Switzerland

Currently, we produce only 1.3 terawatt hours of solar energy, but according to WWF studies, it will be 15.3 terawatt hours by 2035. That is less than in Germany, for example, which is much further along, although the climatic conditions are worse than ours. In Switzerland, solar radiation is higher, at 1050 to 1600 kilowatt hours per square metre per year, depending on the location, and in the Alps it is even comparable to Spain. The sun is an inexhaustible source of energy, which is why solar energy is a cornerstone of the Energy Strategy 2050, which we approved at the ballot box on 21 May 2017. By 2050, 24 terawatt hours of electricity are to be produced from renewable energies such as solar energy, wind power, biomass or geothermal energy. Expanding these energy sources is the simplest climate protection measure.

Houzy Advice

Good to know

The sun shines as intensely in the Swiss Alps as it does in Spain.

A solar system is ecologically worthwhile

Solar energy is not only inexhaustible, but also much more environmentally friendly and climate-friendly than fossil fuels such as oil or gas. For example, if you heat your single-family home with wood and a solar system instead of oil, you reduce your CO2 emissions by more than four tonnes per year. And if you build or renovate your house in an energy-efficient way, you can even cover your entire heating needs with a solar system. This protects the environment because solar power production produces neither air pollutants nor CO2, and at the same time relieves your wallet.

A solar system is economically worthwhile

There are numerous economic arguments for a photovoltaic system on the roof:

  • Reducing your electricity costs by 30 percent in the long term
  • Being independent of electricity price increases
  • Increasing the value of your home in the long term
  • Securing government subsidies
  • Optimising your tax burden

A solar system is an investment. How quickly it pays for itself depends on many factors. If you have a high self-consumption share (see "Factor 6: Self-consumption"), the investment usually pays for itself within 15 to 20 years. So with a lifespan of 30 years, you can save a lot of money for 10 to 15 years. In addition, you produce your own electricity: the more prices rise, the faster the photovoltaic system pays for itself.

Factor 1: The roof

How suitable your house is for a solar system depends on the solar radiation and the size of the roof surface. Solar radiation is significantly influenced by three factors:

  • Solar radiation is most intense when the roof faces south. South-east to south-west deviations minimise electricity production only slightly. In addition, photovoltaic systems with a high level of self-consumption pay for themselves the fastest, which is why it is also worth installing them on roofs that face south-east or south-west.
  • Roofs with a pitch of 30 to 35 degrees are best suited. Once the angle of inclination is higher or lower, the orientation is decisive. If the roof faces south, the influence of the inclination is low. The further the orientation deviates from the south, the more the potential of a solar system decreases if the roof pitch is below 30 degrees or above 35 degrees.
  • Shade leads to significant production losses. On the one hand, because less light is converted into electricity, on the other hand, because the modules of the solar system are connected in series. As soon as a module produces less electricity in the shade, all the other modules also produce less.

The size of the roof also plays an important role, because the investment and maintenance costs per square metre decrease with more surface area. This is why larger areas are usually more profitable than smaller ones.

Solar system: Analyse suitability with the solar calculator

Is a solar system worthwhile?

With our Solar Calculator, you can analyse the solar potential of your roof in just a few minutes and calculate the profitability of a solar system.
Compute solar potential

Factor 2: The costs

In 2020, a Swiss private household with an annual consumption of 4,500 kilowatt hours will spend an average of CHF 932 on electricity, according to the Swiss Federal Electricity Commission. Electricity prices vary greatly depending on the region and grid operator and are made up of four components:

  • The energy tariff for the energy supplied,
  • the grid usage tariff for transporting the electricity to the customer,
  • charges and fees such as concession or energy levies, and
  • the grid surcharge, which is used to promote renewable energies, support large hydropower plants and ecologically renovate hydropower plants.

Solaranlage: 932 Franken gibt ein Schweizer Privathaushalt im Jahr für Strom aus.
The average Swiss household spends more than 900 francs a year on electricity. (Source: Swiss Federal Electricity CommissionStatista)

For an average single-family house with an annual electricity consumption of plus/minus 4500 kilowatt hours, a solar system with 8 kilowatt peak output is sufficient. With 1 kilowatt peak you produce about 900 kilowatt hours of electricity per year, so with 8 kilowatt peak about 7200 kilowatt hours. This means you are on the safe side, even if you need more electricity than originally expected.  A photovoltaic system like this costs about CHF 20,000. If you take into account the subsidies (see "Factor 3: The subsidies") and tax savings (see "Factor 4: The tax deductions"), this system will cost you about 15,000 francs net. In addition, there are annual operating costs of about 1 percent of the investment costs per year, i.e. about 200 francs per year or 6,000 francs over the entire service life of 30 years.

Factor 3: The subsidies

The federal government provides financial support for electricity production from solar systems. If you install a system on the roof of your single-family home, you will receive the so-called small non-recurrent remuneration for photovoltaic systems up to 100 kilowatt peak. The amount of the subsidy depends on the output of the system. For the 8-kilowatt peak system in our example, you would receive around 4,000 Swiss francs as a one-time payment. It is paid out as soon as you have put the system into operation.

Factor 4: The tax deductions

If you subsequently install the solar system on your roof, you can deduct 100 percent of the investment costs from your taxable income in most cantons. If you have received a one-off payment from the federal government, however, you may only deduct the net investment costs (investment costs minus one-off payment). As a rule, the house must be five years old for the investment costs to be deductible. How much tax you save depends on your taxable income and the progression.

Houzy Advice

Good to know

If you are building a new house, the investment costs are part of the construction costs and are therefore not deductible.

Factor 5: The feed-in tariff

You can sell electricity that you do not consume yourself to your energy supplier. In return, you receive a so-called feed-in tariff, which varies greatly from region to region. As a private individual, you can only sell your electricity to your energy supplier and are bound to it - and its prices.

Solar installation: Save electricity costs with a charging station for electric vehicles
If you increase your own consumption, for example with a charging station for electric vehicles, you will use more cheap solar energy than expensive electricity from the grid.

Factor 6: Self-consumption

Your own electricity costs you significantly less than electricity from the grid. This means that you lower your electricity costs if you increase the share of self-consumption and consume more self-produced electricity. That's why you should consume more cheap solar energy than expensive electricity from your supplier. You can increase your own consumption in several ways. For example, if you combine the solar system with ...

  • ... a heat pump
  • ... a battery storage
  • ... a charging station for electric vehicles
  • ... an electric boiler

In addition, you can increase your own consumption if you adjust your behaviour and, for example, do the laundry in the afternoon, because the photovoltaic system produces a lot of electricity then.

Houzy Advice

Good to know

Experts assume that the price of electricity from the grid will increase and the feed-in tariff for solar energy will decrease. That is why you should increase your own consumption.

Solar Calculator: Is a solar system worth it for you?

At least six important factors are included in the amortisation calculation or cash flow statement. Many of these factors depend on your house, the location and your energy supplier. Because the calculation is quite complex and some factors, such as solar radiation, have to be researched first, we have developed the Houzy Solar Calculator for you. It takes into account all the factors we have briefly touched on in this article, including the important subsidies and tax deductions for solar systems.

With the Houzy Solar Calculator, you can analyse the solar potential of your roof in just a few minutes, calculate the profitability of a solar system and simulate various self-consumption scenarios.

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