What will a CO2-neutral Switzerland cost us?
According to a Federal Council decision of August 2019, which was adopted by the Federal Council in January 2021 as a long-term climate strategy, Switzerland is to become climate-neutral by 2050. But what does that mean in practice? How can these goals be achieved, what will it take and what will it cost? Andras Züttel, head of the LMER in Sion, a joint research center of Empa and EPFL, has now made a detailed calculation together with former Empa director Louis Schlapbach and published it in the journal Frontiers in energy research.
Electricity, hydrogen or synfuels?
The researchers calculated three different energy systems and compared them with today’s energy costs of around CHF 3,000 per capita and year. The first challenge is to replace Switzerland’s nuclear power plants, which are scheduled to be shut down by 2050. This alone requires a solar roof area of 16 square meters per head of the Swiss population. An accumulator of 9 kWh is required per inhabitant in order to store the electricity harvested during the day into the night. In addition, four large pumped storage power plants the size of the Grande Dixence power plant are required to store the summer electricity for the winter. This basic assumption applies to every scenario.
A new hydroelectric power station every year
The most efficient way is to electrify the entire energy supply, says Züttel. If all cars and trucks were electric and all buildings were heated with heat pumps, the electricity demand per capita would increase by almost 1,000 watts – in addition to today’s electricity consumption. In order to generate this amount of energy, Switzerland would need 48 square meters of solar area per capita (three times the available roof area in Switzerland), an additional 26 kWh storage battery per capita and for summer/winter storage an additional 13 pumped storage power plants with 1500 GWh each – which is the size of the corresponds to the Grand Dixence power plant. Energy researcher Züttel calculates: “If we start immediately, we would have to build a new dam every year until 2035.
25 Gotthard tunnels full of hydrogen
The second option would be a hydrogen economy. However, climate-neutral hydrogen is produced from solar power, and part of the energy is lost during its conversion. Scenario number 2 would require 116 square meters of solar surface per capita – and a day-night storage of 57 kWh per capita. Hydrogen could then be used to power cars, trucks and buses, and catalytic burners could be used to heat all buildings. Additional storage would not be necessary with this variant, but the hydrogen produced in the summer would have to be stored in underground caverns at a pressure of 200 bar. Züttel calculates: “We need a volume of 57 million cubic meters – that’s about 25 times that of the Gotthard base tunnel.” The energy costs for this variant would increase by around 50 percent, ie from the current 3,000 francs per capita to around 4,400 francs per capita and year.
12 times the roof area of Switzerland
Option three is to supply the entire country with synthetic fuels (synfuels) from green electricity. Homeowners would continue to run their oil and gas heaters; Car owners would continue to fill up with diesel, petrol or gas. Even kerosene for airplanes is included in this calculation (in scenarios 1 and 2, 33 square meters of additional solar area per capita would be needed for aviation fuel!)
New reservoirs or underground hydrogen caverns would not be necessary here. But for this scenario, 4.5 percent of the Swiss land area would have to be covered with solar cells – that is 12 times more than the roof area available today. A storage battery of 109 kWh per capita would also be needed to store the huge amount of solar electricity at noon and make it available to the chemical industry, which would first produce hydrogen and then synfuels from it. Energy costs would more than triple – from CHF 3,000 per capita today to CHF 9,600 per capita and year.
Going it alone nationally is not possible
Züttel points out that not just any energy price is economical. “Ever since the industrial age began more than 200 years ago, the economic performance of every country has been linked to the availability of energy. But in order to create an economic benefit, primary energy must not cost more than 40 centimes per kWh, otherwise industry will work at a loss,” says the researcher produced, renewable energy.”
Züttel recommends a global view: In places like the Sahara or Australia, the solar radiation is so high that synfuels can be produced a third cheaper. “We cannot do without global energy logistics in the future.”
diary
Frontiers in energy research
research method
case study
subject of research
Not applicable
article title
Future Swiss energy economy: The challenge of storing renewable energy
Article publication date
February 1, 2022
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