> In reality, it's impossible for a households to get a contract that follows market rate, you always pay the same per kWh no matter if it's Sunday or Monday, windy or calm.

In the UK you can use the Agile tariff from Octopus Energy (https://octopus.energy/agile/) which has half hourly dynamic pricing per electricity kWh. The next 24hrs worth of prices are released each day around 4pm and follow market cost. There’s a 12p/kWh surcharge between 4pm and 7pm during peak demand. Used in conjunction with a smart meter it bills per half hour usage and can go negative.

Twice in the last two week’s it has gone below zero due to recent storms. It’s a great tariff if you have an electric car to charge in the early hours when prices are cheapest and can reduce usage during the peak three hours. A home battery would also help out as it could be charged during cheap periods and discharged when prices are too high.