The bigger experiments will routinely burn through tens of millions worth of computing. But 10 million euros isn't much for these experiments. The issue is that

The bigger experiments will routinely burn through tens of millions worth of computing. But 10 million euros isn't much for these experiments. The issue is that they are publicly funded: any country is much happier to build a local computing center and lend it to scientists than to fork the money over to an American cloud provider. (The expensive part of these experiments is simulating billions of collisions and how the thousands of outgoing particles propagate though a detector the size of a small building. Simulating a single event takes around a minute on a modern CPU, and the experiments will simulate billions of events in a few months. If AWS is charging 5 cents a minute it works out to tens of millions easy.)