"Renewable" Electricity Champion Denmark Now Looking Into Nuclear

At this site, when I have written about countries and states seeking to be among the leaders in eliminating fossil fuels from their electricity supply, I have generally focused on the larger jurisdictions, like Germany and the UK in Europe, and California and New York in the U.S. But there is one much smaller country that puts all of those bigger ones to shame: Denmark. With a population of only about 6 million, Denmark has pushed the “renewable” electricity generation thing well beyond what others have been able to accomplish. According to its official statistics, in 2024 Denmark got some 79.5% of its electricity from what it calls “low carbon” sources. The large majority of that came from wind and solar, with only a minimal contribution from nuclear. As to nuclear, Denmark had in fact banned it by a law going all the way back to 1985.

So then, does it seem like, with just a final little push, Denmark can go over the top and reach the long-sought goal of 100% of generation from “renewables”?

In fact, according to the most recent news from Denmark, it is the opposite. Just during the past week, Denmark has re-opened consideration of adding nuclear reactors to its generation mix. The immediate impetus for the resolution appears to have been the recent blackout in Spain and Portugal, which has been generally attributed to the lack of synchronous generation on the power grids of those countries.

Now that Denmark has recognized the need for some form of high-inertia synchronous generation to make its grid work reliably, it’s hard to see how they can avoid the next inevitable question: Do wind and solar actually serve any real function here? Or are they just a large added cost without any corresponding benefit? It can’t be long before lots of people start pressing this obvious question.

Denmark’s change of course is reported in this May 14 piece from Oil Price:

Denmark’s government has started weighing the opportunities and risks of lifting a 40-year-old ban on the use of nuclear energy, Minister of Climate and Energy Lars Aagaard said on Wednesday.  Denmark banned the use of nuclear energy in 1985, after the Parliament voted to remove nuclear power from the country’s energy planning. . . . Now Denmark is considering the potential and risks of using advanced nuclear technology such as small modular reactors (SMRs), the energy minister said.  “We observe that new nuclear technologies are emerging – small modular reactors. The government has decided to institute an inquiry of the potential of these new nuclear technologies,” Danish newspaper Politiken quoted Aagaard as saying today.

And meanwhile, up to now Denmark has been the absolute champion of building wind turbines and solar panels to supply its grid. Since the 1990s, Denmark has had a crash program to build out more and more wind and solar generators. According to Danish statistics reported at Low Carbon Power here, in 2024 Denmark got 52.3% of its electricity from wind and 10.2% from solar, for a total of 62.5% from those two sources. Here is a pie chart from Low Carbon Power showing all of the sources of Denmark’s electricity for 2024:

The “low carbon” total comes to 79.5%, after adding an additional 17% from a category they call “biofuels.” Note the leafy branch appearing in the pie chart as the symbol for the “biofuels.” Don’t be fooled. As far as I know, “biofuels” mainly means burning garbage, with some wood pellets from cutting down trees thrown into the mix. Both garbage and wood pellets contain carbon, and thus the energy from the “biofuels” comes from burning the carbon. Exactly why this is in the “low carbon” category is a mystery to me.

But with or without the biofuels, Denmark has well surpassed other de-carbonization “leaders” in getting its electricity from “renewable” sources. Compared to Denmark’s 62.5% of electricity from wind and solar in 2024, Germany in 2024 got a combined 43% of its electricity from those sources (28% wind and 15% solar), while in California the percentage from the two sources was 37.5% (12.5% wind and 25% solar). For their virtue, the Danes got to enjoy average residential electricity prices of 37.63 euro cents per kWh.

And yet, having surpassed the 60% threshold of electricity from wind and solar, Denmark has now recognized that 100% is not feasible, and wind and solar alone cannot be the only sources to power their grid. Even if the intermittency problem can be overcome, the problems of lack of sychronization and inertia cannot be solved with only wind and solar. Some amount of timed spinning generation is necessary, and nuclear is the proposed low-carbon solution. Some amount of nuclear is going to get built. Let’s assume the amount of nuclear to be built will be sufficient to supply 50% of average demand (the exact percentage is not important).

Once you have nuclear to supply half of average demand, here’s the key question: should you run it all the time, or should you turn it on and off, or ramp it up and down, as wind and solar generation may be available to meet the same demand? This is not a difficult question. Nuclear reactors are expensive, and the cost of the capital needed to build them (e.g., interest on bonds) accrues 24 hours a day and 365 days a year. To minimize the cost of capital per unit of electricity produced, you want to run your nuclear plant all the time. Yes, there is a cost of fuel involved in a nuclear plant, but it is minimal compared to the cost of capital.

Instead of running your new nuclear plant at full capacity all the time, you could choose to have it ramp up and down as intermittent wind and solar generation are randomly available. Assume that (like Denmark) you have sufficient wind and solar generation to supply 62.5% of demand. This means that your new nuclear plant, operating in backup mode, will only be selling power 38.5% of the time. But the bondholders who financed it must be paid 100% of the time. After some (relatively small) adjustments for costs of fuel and operations, the bottom line is that the cost per unit of electricity from your new nuclear plant will be close to triple what the cost per unit would have been if you had chosen to run the plant all of the time. But if you run the nuclear plant all the time, you don’t need the wind and the solar. They are just a useless extra cost.

The real world cost calculations would be somewhat more complex than what I have outlined, but not much. The fact is that once you have nuclear plants to cover a given level of electricity demand, wind and solar generators serve no useful function.

It shouldn’t take the Danes too long to figure this out. I will enjoy watching the process unfold.

UPDATE, May 20: A commenter points out that I incorrectly included in this post a link and quote from an article that discusses Belgium rather than Denmark. The situation in the two countries is quite similar — both are reconsidering expanding nuclear electricity generation after a long period of banning it — but Belgium has not gone quite so far as Denmark down the wind/solar blind alley. I have made some edits to the post to refocus it on Denmark.