What will a CO2-neutral Switzerland cost us?

image: Andreas Züttel, head of the joint Empa-EPFL energy research center “Laboratory of Materials for Renewable Energies (LMER)” in Sion, Switzerland.
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Credit: Empa

Switzerland must become climate neutral by 2050, according to a resolution adopted by the Federal Council in August 2019, which was adopted as a long-term climate strategy by the Federal Council in January 2021. But what does this mean? concretely ? How do you achieve these goals, what will it take and how much will it cost? Andras Züttel, director of the LMER in Sion, a joint research center of Empa and EPFL, together with former Empa director Louis Schlapbach, has now made a detailed calculation and published it in the journal Frontiers of energy research.

Electricity, hydrogen or synthetic fuels?

The researchers calculated three different energy systems and compared them with current energy costs of around 3000 Swiss francs per inhabitant per year. The first challenge is to replace the Swiss nuclear power plants, which are to be closed by 2050. This alone requires a solar roof area of ​​16 square meters per inhabitant of the Swiss population. For each inhabitant, a 9 kWh storage battery is needed to store the electricity harvested during the day until the night. In addition, four large pumped storage power stations the size of the Grande Dixence power station are needed to store summer electricity in winter. This basic assumption applies to all scenarios.

A new hydroelectric plant every year

It is more efficient to electrify the entire energy supply, says Züttel. If all cars and trucks were electric and all buildings were heated with heat pumps, the amount of electricity needed would increase by just under 1,000 watts per capita – on top of energy consumption current electricity. To produce this amount of energy, Switzerland would need 48 square meters of solar area per inhabitant (three times the available roof area of ​​Switzerland), an additional storage battery of 26 kWh per inhabitant and, for the summer-winter storage, 13 additional pump storages. plants of 1500 GWh each – which resembles the size of the Grand Dixence plant. Energy researcher Züttel calculates: “If we started immediately, we would have to build a new dam every year until 2035. But we simply don’t have enough suitable valleys in the country for such a scale.

25 Gotthard tunnels filled with hydrogen

The second option would be a hydrogen economy. But climate-neutral hydrogen is produced from solar electricity, and some of the energy is lost in the conversion process. Scenario number 2 would require 116 square meters of solar space per capita – and a day-night storage battery 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 tanks would not be needed for this variant, but the hydrogen produced in the summer would have to be stored at 200 bar pressure in underground caverns. Züttel calculates: “We need a volume of 57 million cubic meters – that’s about 25 times the Gotthard base tunnel.” The energy costs of this variant would increase by around 50%, i.e. from the current 3,000 francs per inhabitant to around 4,400 francs per inhabitant per year.

12 times the area of ​​the roofs of Switzerland

The third option is to supply the whole country with synthetic fuels (synfuels) from green electricity. The owners would continue to operate their oil and gas heating systems; 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 underground hydrogen tanks or caverns would not be needed here. But for this scenario, 4.5% of Switzerland’s national territory should be covered with solar cells, ie 12 times more than the roof surface available today. A 109 kWh per capita storage battery would also be needed to store the huge amount of solar energy at noon and make it available to the chemical industry, which would use it to first produce hydrogen and then synthetic fuels. The cost of energy would more than triple – from 3000 francs per inhabitant today to 9600 francs per inhabitant per year.

No solo national effort possible

Züttel stresses that any energy price is not economically viable. “Since the beginning of the industrial age well over 200 years ago, the economic performance of every country has been linked to the availability of energy. But to create an economic benefit, primary energy must not cost more than 40 cents per kWh, otherwise the industry will operate at a loss,” explains the researcher. “So we have to abandon the idea that we can meet all our energy needs with locally produced renewable energy.”

Züttel recommends taking a global view: in places like the Sahara or Australia, he says, solar radiation is so high that synthetic fuels can be produced a third cheaper. “We cannot do without global energy logistics in the future.”

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