The local council did a great job for the referendum on September 22nd and ensured that eight votes were presented to the electorate. The voting “booklet” is quite thick at 96 pages. The SK TED/DIB committee, which I chair, has also discussed two voting proposals in advance: firstly, the EWZ loan of 300 million francs for the further expansion of renewable electricity production. But there are probably more question marks about the other proposal, the CO₂ capture on the Werdhölzli site, which costs a one-off fee of 35 million francs, but also an annual recurring fee of 14.2 million francs.
Long before I joined the local council four years ago, the question was asked whether the large amount of CO₂ that is produced, for example, at the Hagenholz waste incineration plant, could not simply be captured. This question has been found in old minutes for decades. The city administration has regularly responded that the technology for capturing CO₂ has been known for a long time, but that they do not know where to transport it.
Hagenholz produces 200,000 tonnes of CO₂ annually. This amount can probably only be transported away via pipelines. As desirable as it would be to remove all of the CO₂ from Hagenholz immediately, from a technical point of view it makes sense to first gain experience with a smaller project: the Werdhölzli site. The sewage sludge incineration there produces 23,000 tonnes of CO₂ annually, which can be transported away by truck.
The permanent storage of CO₂ and thus its removal from the cycle was put out to tender, and in contrast to previous times, a partner company was actually found which, on the one hand, adds CO₂ to Swiss recycled concrete and, on the other hand, permanently inserts it into the rock in depleted oil fields in the North Sea, so that Zurich can thereby “generate negative emissions”.
The transport and storage of CO₂ also cause CO₂ themselves, but the overall balance is impressive: with the recycled concrete variant, around 96 percent of the CO₂ is permanently removed from the cycle, and the North Sea variant also achieves a good value of just over 90 percent.
The costs are quite high at over 600 francs per tonne of CO₂. But we have also imported and burned oil from the North Sea fields in Zurich, so it is obvious that we will use these fields again for the necessary CO₂ disposal. Without such “negative emissions” we will not achieve the net zero target for 2040.
