If you choose an hourly rate contract, you will have an electricity price that follows the development at Nord Pool, or at one of the other electricity exchanges active in Sweden, on an hourly basis.
This means that your cost for electricity is affected by the time during the 24-hour day when you use the electricity.
The main advantage is that you can avoid consumption during the most expensive hours of the 24-hour day (which are usually during early morning and late afternoon/early evening), and instead choose to consume electricity during the hours when prices are lower (which are usually during the middle of the day or at night).
An hourly rate contract will suit you if you want to and can adapt your consumption to the hourly rates at the electricity exchanges. It may mean you need to replace your electricity meter (which is free of charge). In order to derive as much benefit from the contract as possible, it can be a good idea to investigate whether there is electrical equipment in the home that can be automatically controlled according to hourly rates, such as a heat pump.