It sort of depends on what you mean by markets. In most places in Europe the production of power is on the market, but the actual power grid is not freely traded. The grid is instead handed out to semi-permanent monopolies that are heavily regulated and controlled by governments and/or non-profit NGOs that are essentially a way we do efficient government in the supply sector.
It works, but the benefit isn’t usually to the consumers despite that being the intention. We’re currently seeing a load of insider trading and price manipulation cases roll into court after the price hikes following last years gas craze, and over all, power prices haven’t really gone down.
In many ways it’s mostly been a way to divert public money from the public services and into private investors. The way I pay for my electricity is that I pay for the grid, which is the non-freely-privatised part of your electricity market and makes up around 50% of my bill. Before it was privatised it was 90% less expensive. The other 50% is the actual electricity that I buy, we currently buy ours from a company of two people who buy and sell electricity on the European markets. This part is cheaper than it was before it was privatised, but the profits go to those two people and not into advancement of our electric grid.
The prices of electricity are also sort of heavily dependent on the government. A huge part of the income you get from running something like a solar plant is often going to be tariff because the EU can’t/won’t allow green energy to be traded freely as it would bankrupt fossil fuel plants, and you sort of need those since they can scale power at any time. Of course if it wasn’t privatised you could spend those tariffs, green euro and other subsidies on actually building the sector like you did with nuclear and fossil fuels. Not that I mind, I work in an investment bank that builds energy plants and sell them, so it’s good money, but it’s also sort of silly financially.
Like in Germany you have Tariffs where you only get the tariff if you don’t exceed the production max that’s set politically. So if you produce up to 99.9% you get your free money, but if you produce 100.1% you get zero tariff money. You obviously still get paid from the electricity production at whatever rate it’s capped at, at any given time. Then on top of that the government is paying you to shut down production during peaks so you don’t flood the European grid beyond capacity. Which is fine for us, but also sort of silly for consumers since it’s their tax money that’s basically used to make energy production a lucrative business for us.
So yeah, it works, there is a lot of money in it, and a lot of job creation, but it’s not really a net benefit for your consumers.