I had posted earlier about the mystery of my bill from Vattenfall, and why I seemed to have such a big credit.
Rutger got to the bottom of it, and it turned out to be fairly simple. My first bills were based on the usage of a year-round house. Since our home isn't occupied that often, we used a lot less electricity than estimated, and so I built up a big credit.
He also saw that I should have been repaid about 1200 kronor of my overpayment into my bank account this spring; in fact their bill said they would refund me, but they didn't. After some strong complaints about this treatment, Rutger got them to agree to give me a further 500kr credit. Wow!
Rutger also advised that I was paying the 'full' uncontracted rate of 69.5 öre per kilowatt, which I could lower significantly with a long-term contract. I emailed Vattenfall and they responded (in English) that I could get a fixed 3-year price of 47.3 öre, which is what I've done. I've also signed up to get all my bills online.