Rooftop photovoltaic potential in Switzerland

Switzerland in 2016 generated 174 kWh per capita from solar panels. This is equivalent to less than one square metre of photovoltaic panel per person. If Switzerland used around 4% of suitable rooftops for photovoltaic installations, it could replace all non-hydroelectric power for household requirements for the future.

The average Swiss household consumes around 5.2 MWh of electricity per year. PV installations in Switzerland can produce about 1.2 MWh of electricity per square meter per year. This means that the average household needs 4.3 m2 of rooftop solar panels to cover its electricity needs at current consumption rates. Since 60% of power is covered by hydropower, Swiss households actually only need 1.7 m2 (c. 4% of available surface area) per household to replace nuclear power and obviate the need for fossil fuel power generation in household electricity consumption.

  • Total Swiss household electricity consumption (2016): 19 TWh (32.8% of all electricity)
  • Final total of all electricity consumption per capita: 7.0 MWh
  • Final consumption per household: 5.17 MWh
  • Final consumption per household per capita: 2.3 MWh
  • Average PV generation at 15% efficiency: 3.3 kWh/m2/day or 1.2MWh/m2 p.a.

Switzerland has the good fortune never to have needed fossil fuels for electricity generation, instead relying on 60% hydropower, and 36% nuclear. As its 5 nuclear reactors are shut down gradually by 2034, there is much debate about how the missing electricity will be made up.

Wind energy is not a major contender, except in the Jura (eastern Switzerland), and some Alps. However, there is a lot of solar potential, particularly roof-top, as well as biomass, geothermal and about 5% more hydropower, including more use of elevated pumped storage.

Switzerland has been referred to as the ‘battery of Europe’ because it can offer the Europe-wide network considerable load-balancing potential through its pumped storage.

In 2017, Switzerland consumed 237 TWh of energy, or 0.15% of the world’s demand. This is 40% above the average consumption per capita, since Switzerland is 0.11% of the global population. Except that if grey energy is included in the calculation. Then Switzerland’s energy consumption is twice the above figure. To cover the energy demand of CH, 948 km2 of African land would need to be covered in solar panels. That is equivalent to 2.3% of the surface area of CH. Of course, solar radiation is much lower in CH, so more land would be required to make CH energy independent. With grey energy, CH would need 10% of its land to be solar energy productive to be 100% solar.

CH has 33 TWh of solar potential using rooftops and other infratructure which are suitable for solar installations.

Rooftop Potential

In Switzerland, 174 kWh of solar power and 13 kWh of wind power were produced per capita in 2016, which is very small compared to the other European countries, ranking Switzerland at a poor 25th out of 29 for overall solar and wind renewable electricity generation. The frontrunner, Denmark, produces 12 times as much per head.

Each household consumes 5.17 MWh on average (2016), and PV in Switzerland on average produces 1.2 MWh/m2 p.a. This means that 4.3 m2 of PV per household is required for 100% own power. This is 19 TWh, which is approximately the total output of all the nuclear reactors.

The Swiss Federal Office for Energy SFOE calculates PV potential in Switzerland to be 50 GWh, or 90% of current consumption. So what is keeping solar in the shadows? To get a sense of the scale. The five nuclear plants generate 19-20 TWh of power. The household electrical power consumption in 2016 was the same, 19 TWh. On average, each household consumes 5.17 MWh of electrical power for lighting, appliances, and heating. Photovoltaic panels under Swiss conditions can generate 1.2 MWh per square metre over a year. This means that 4.3 m2 of PV per household is required to generate the amount of power it consumes. If this power were usable immediately, avoiding loss through storage in batteries, and total grid integration, then PV could replace all nuclear power by an investment of 4.3 m2 (the surface area of two and a bit doors), which at current market prices would cost 1500 Fr.

Multiplied by the number of households, 3 million, the 4.5 billion pricetag looks very good compared to the 20-30 billion the equivalent in new nuclear power or coal stations would cost. And this calculation is based on today’s prices. With economies of scale, increasing efficiency in PV technology, smart grids and homes, demand for power for heating and electric vehicle charging (immediate use of solar power), the costs for solar energy can only come down. At the same time,

the costs for nuclear and fossil fuel generation can only increase, with price of fuel fluctuations, the upcoming carbon tax, and the increasing price of carbon emission certificates.

In addition, being a low-maintenance domestic infrastructure that will last for more than 25 years (a nuclear power plant has a lifetime of 35 years), it is an investment for a future that is free from foreign supply risks and market fluctuations in a world of growing uncertainty. And, of course, renewable energies employ between five and ten times as many people as conventional energies, paid for by the savings on fossil fuel and uranium purchases made abroad, which currently is over 10 billion SFr annually.

Household consumption = 19 TWh or 32.8% of all electricity in 2016. Per household = 5.17 MWh (2.3 MWh per head).

Total electricity per head consumption (including industry, commerce, transport, etc.) = 7.0 MWh