Firstly, Denmark's renewables are largely wind. But wind and solar are negatively correlated. As they add more solar, the variability will cancel out.
Secondly, variability is heterogeneous across geography. You're not building the second wind turbine in the same location as the first. As you connect countries up, or as you build in locations that don't currently have it, the variability cancels out.
Denmark is tiny. If the EU takes it up as a project, significant amounts of variability cancelling will happen, as you mix offshore wind, onshore wind, and solar, across the continent.
So, > 80% of EU's energy, from wind and solar, without any storage, should be achievable.
> running at high overcapacity results in significant less profits
Still better economics than nuclear. Even if you're at 3x overcapacity, it's still cheaper[1]. Not to mention you can sell most of that overcapacity (even to countries outside the EU) and get the money back, or convert it into green hydrogen and sell that.
Well, Denmark is tiny so if its not windy in one location then its unlikely to be very windy in an other. Same for the sun.
EU has however already taken it up as a project. It is called the European energy grid, which as I describe above forces countries to sell to each other. There is an economical limit to this from transit and transport costs, but in concept the whole union is already a single grid connected from the southern part of Italy to the polar circle in northern Sweden and Finland.
Denmark consumes around 33 Terawatt of electricity. They import 20 Terawatt. They also sell about 14 Terawatt of renewable energy. Sweden (hydro + nuclear), Norway (hydro), and Germany (coal, gas) are the main players that provide those 20 terawatt of electricity to Denmark.
This far up north the sun doesn't cancel out the still periods of wind. Demand for heating during winter far exceeds the few hours of sun that you get.
Green hydrogen, as nice as it is for reducing the emissions from steel industries, still costs about 10x of nuclear if you use that green hydrogen to produce power. There is a big economical reason why no one is doing that at this point in time. Estimates from researchers in the field varies from around 2035 to 2055 before we will have our first commercial green hydrogen power plant in operation. Still green hydrogen would be a nice way to recover costs if Denmark did decide to go for 300% overcapacity, but they would still need to heavily depend on Sweden, Norway and Germany to provide the electricity when demand exceeds supply. Their own grid will not suffice.
Why doesn't solar cancel wind far up north like it does elsewhere? The sun shines longer in the summer, and it's less windy in the summer.
"Well, Denmark is tiny so if its not windy in one location then its unlikely to be very windy in an other. Same for the sun."
That's true to a large extent for Denmark, but untrue to a large extent for the EU or larger countries. That's why I said that the EU can get over 80 percent of its energy just from renewables without storage, for a cost significantly cheaper than nuclear.
Firstly, Denmark's renewables are largely wind. But wind and solar are negatively correlated. As they add more solar, the variability will cancel out.
Secondly, variability is heterogeneous across geography. You're not building the second wind turbine in the same location as the first. As you connect countries up, or as you build in locations that don't currently have it, the variability cancels out.
Denmark is tiny. If the EU takes it up as a project, significant amounts of variability cancelling will happen, as you mix offshore wind, onshore wind, and solar, across the continent.
So, > 80% of EU's energy, from wind and solar, without any storage, should be achievable.
> running at high overcapacity results in significant less profits
Still better economics than nuclear. Even if you're at 3x overcapacity, it's still cheaper[1]. Not to mention you can sell most of that overcapacity (even to countries outside the EU) and get the money back, or convert it into green hydrogen and sell that.
[1] https://ourworldindata.org/cheap-renewables-growth