"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 mandated phasing it out, by a law passed back in 2003.

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, the lower house of Denmark’s Parliament, by a wide margin (102-8), passed a resolution reversing the nuclear phase out. This will likely lead to retaining the few remaining reactors, and then starting to build new ones. 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. The statement by the Danish government announcing the Parliament’s resolution did not explicitly walk back support for the continued build-out of wind and solar generators, but said that this new pro-nuclear approach “pave[s] the way for a realistic and resilient energy model.”

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.

A brief history of how Denmark got to where it is can be found in this May 16 piece from World Nuclear News. Excerpt:

Belgium's federal parliament has voted by a large majority to repeal a 2003 law for the phase-out of nuclear power and banning the construction of new nuclear generating capacity. Meanwhile, the Danish parliament has approved an analysis of the potential use of nuclear, which has been banned for the past 40 years. Belgium's federal law of 31 January 2003 [has] require[d] the phase-out of all nuclear electricity generation in the country.

Under the 2003 law, several nuclear plants had been closed, although the closure of the last two had been delayed. Most recently, those last two were scheduled to close in November of this year, but now that is likely to be postponed again.

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.