Sorry to say that but opera is a really bad choice for privacy, actually on of the worst. https://youtu.be/k8hUs0W-UWY

weint in 24h Bereitschaft im Krankenhaus

The thing is that efficency doesn’t matter too much if this energy used is from intermittent sources like wind or solar and if there is too much energy at this moment and not everything can be used. So it is better to safe energy at lower efficiency than not saving anything at all.