Last year, renewables provided more than half of Germany’s annual electricity consumption for the first time. I’ll use the occasion to show long-term power generation stats (with preliminary 2023 numbers) and point out some trends. The situation in Germany is subject to policy debates worldwide due to the phase-out of nuclear energy (adopted in 2002, completed also last year) and the parallel early adoption of renewables, but those discussions usually miss some key developments, which I hope to highlight.
The first thing you’ll notice that while nuclear was phased out, fossil fuels also fell, even the dirtiest, “brown coal” (c. lignite, although classification of coal grades is a bit different in Germany). Germany has now also adopted a law on phasing out coal. This could and should have happened much earlier, but politics got in the way (in spite of a much wider popular support, basically only the Greens party was seriously endorsing it for the past 25 years; but they were junior partners in the federal government only in 1998-2005 and currently from 2021).
Next, some less obvious stuff. When discussing different methods of power generation, especially when it comes to decarbonisation, it is often forgotten that the different methods are best suited for different load regimes, and also what those load regimes truly mean. The simplest classification distinguishes only two loads (base & peak), but for any sensible discussion, we need at least three:
- Baseload: power plants always operated at the maximum possible. This is usually equated with constant power, but it isn’t truly: scheduled (refuelling) & unscheduled (accident) power-downs, external restrictions (e.g. river used for cooling running low) bring in variation. In Germany, before the transition, there was a very clear separation as this regime was almost identical to nuclear and brown coal plants. However, arguably, now wind and solar power are in the same regime: they may be constantly variable (intermittent) due to weather, but that intermittency is largely predictable, and the plants are operated at the maximum possible.
- Intermediate or scheduled load: since both baseload and consumption can be predicted a day ahead with relatively good accuracy, it is possible to schedule the generation of most of the difference in advance, using power plants whose output can be regulated on a timescale of hours. In Germany, before the transition, almost all of the anthracite coal plants and part of the natural gas plants were operated in this regime. Hydro can also operate in this regime, also biomass, and also different methods of energy storage (which is still primarily pumped hydro).
- Peak load: to deal with unforeseen events like slower deviations from predicted production & consumption, outages and sudden power surges, power system managers rely on power plants that can be powered up or regulated on a timescale of minutes or even seconds. In Germany, traditionally, this has been the task of natural gas and mineral oil plants, and still is.
(For a bit longer explanation of load regimes with example diagrams, you can consult a diary I posted at Eurotrib back in 2010.)
If you consider load regimes, you’ll see that the task of decarbonising electricity generation is more complex & difficult: it is much easier to replace baseload than the other two, and you’ll realise that the whole recent discussion in Europe about keeping nuclear to reduce gas imports from Russia is nonsense as one cannot replace the other. (Shutting down lignite plants before nuclear ones would be another, more sensible thing.)
Still, one can ask, what effect does the energy transition have on the load regimes, considering the intermittency of renewables? Counter-intuitively, on the diagram, you’ll notice that the combined share of anthracite coal and natural gas has shrunk! How could this be? The answer is what I call natural balancing: when you have significant shares for both of the two key intermittent renewables, wind & solar, then on average, their combined power won’t be constant but loosely resemble the variation of consumption, and that both on the daily (diurnal) and seasonal timescale. This will reduce the annual demand for intermediate load. (I note this was still largely theory when I wrote that 2010 diary but now in effect in multiple European countries.)
You’ll also notice that during the years of renewables expansion, the balance of exports & imports became positive, with last year being the only exemption. This diagram, however, is not enough to show the actual movements, but they are interesting, so I list them briefly:
- Germany gets net imports from Scandinavian countries, especially Denmark, and the source of that power is overwhelmingly renewables, too. (Over half of electricity generated in Denmark comes from wind power, almost all of it in Norway from hydro, and most of it from both hydro & wind in Sweden.) For Denmark, in particular (which started to expand solar power significantly only very recently), the exports to Germany have a strong balancing role.
- France has the world’s highest share of nuclear power, and one way it deals with the need for balancing is variable exports (in effect, France and the importing countries form a single system where France provides baseload & gas plants in Italy or the Netherlands provide intermediate power). For this, Germany has been a key transit country; last year, the main targets have been Switzerland, Poland & Austria.
- Another way France sought t reduce its balancing needs was to popularise electric heating. However, during cold spells, this leads to demand surges, briefly turning France into a net importer. In recent years including last year, this phenomenon overtook the transits in volume and Germany had net exports vs. France.
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Germany’s present federal government is a coalition between the Social Democrats (traditionally strongly aligned with coal producers & gas), the Greens (the most consistent supporters of renewables) and the Free Democrats (currently proponents of free-market capitalism who traditionally opposed any government support schemes), and after hard internal battles, they adopted new policies that significantly boosted new installations in renewables last year (generation numbers obviously don’t yet fully reflect that). It’s still way behind what would be possible — this diary is already long enough without an explanation of feed-in laws vs. certificates or recounting the history of policies undermining a faster transition during the years of Chancellor Angela Merkel —; still, if the current policies continue, expect stronger shifts in the shares of different power generation modes in the coming years.