In October I spoke to Dr. Harald Schwarz, a professor of engineering at the Brandenburg Technical University who has dedicated his career to researching Germany’s electricity grid.

I recorded the whole conversation as a podcast. In a nutshell, Dr. Schwarz is pretty pessimistic about the direction things are going. He believes that politicians made bad choices long before the Ukraine war that will cause havoc on the electricity grid in the future.

In today’s newsletter I sum up the key take aways.

Why is the German grid so unstable?

An electricity grid is only stable as long as generation follows demand almost exactly.

In the old days, coal and nuclear would supply the base load, while gas-fired stations would meet the hours of peak demand. These traditional forms of electricity production have a secured capacity of around 90 percent. Besides being off line for the occasional repair work, they are always ready to go. So meeting demand is not a problem.

Wind and solar, on the other hand, have a secured capacity of close to zero. They generate electricity completely independently of demand. The sun doesn’t care if lots of people are using their washing machines. Nor does the wind notice whether we are charging our Tesla. If there is even a short period of no wind and now sun, renewable generation cannot meet demand.

Prof. Schwarz:

“The question is how to deal with the gap. If the forecast for tomorrow is that solar output drops from 100 percent to 20 percent, who will deliver this difference? You normally need power stations in your own country that are ready to deliver at any moment of the year.”

But, as he points out, Germany has slowly reduced the number of stations it has that can deliver at any minute of the year. In 2011, the government decided to switch off all nuclear by 2022. In 2020, it decided to shut down all its coal-fired units. And now it is no longer receiving gas from Russia.

“We are not paying the price for not having enough renewables, we are paying the price for moving out of nuclear and coal at the same time.”

Offshore wind provides stable supply, right?

Advocates of renewables often claim that offshore wind is the answer. Due to the fact that there is almost always wind at sea, they say that offshore can replace fossil fuels in giving stable supply.

Is that true?

Nope, says Prof. Schwarz:

“Secure supply means at any minute of the year. If you take generation by offshore wind you will find moments of very low production. If you take German offshore wind, there is a secured generation of 2 percent, for onshore its 1 percent, from solar its obviously nothing because the sun doesn’t shine at night. In the whole of Europe you will get 7 or 8 percent secured output. But you have no chance of getting the electricity from Portugal to Germany.”

Why might this cause a blackout?

Because generation needs to exactly meet demand at every minute of the year, if you get a situation where there is no wind and no sun - and you no longer have enough generation from traditional sources to cover the gap - then you are in trouble.

The grid in Germany - and in the whole of Europe - is based on generation at a frequency of 50Hz. If demand outmatches supply, the frequency drops.

Prof. Schwarz explains:

“There is limit (in the system) which is 49.8Hz, if the frequency drops below this then all the reserves in the system will automatically be activated to push the system up. If that is not enough so that frequency drops again then we have to switch off load. That’s the point when the first parts of the grid will be switched off. Between 49Hz and 48Hz you switch off more and more consumers and when you reach 47.5Hz then all the power stations will be switched off. Then you will have a European blackout.”

This actually almost happened in January of 2021.

A period of ‘dark doldrums’ (no wind, no sun) meant that Germany couldn’t cover its own electricity needs, so it had to buy from other European countries. The only problem was that both France and Spain also had to import on the same day (France due to a lack of personnel at its nuclear plants). All three countries ended up buying from Bulgaria and Romania.

Prof. Schwarz:

That meant these two countries (Bulgaria and Romania) operated all their old coal-fired units on maximum output… They bought six or seven gigawatts from these two countries, then they tried to transport it over the Balkans. Unfortunately the European system was never built to transport electricity on a national scaling… Suddenly one small sub-station in Croatia was overloaded and within a couple of minutes all the lines from the Balkans going north switched off.”

Calamity was avoided on that occasion by taking large industrial sites in France and Italy offline. But Prof. Schwarz warns that the outlook is worse for the coming winter due also to France’s massive maintenance problems with its nuclear reactors.

“Next winter is more critical in France and more critical in Germany. For sure they will try to buy somewhere in Europe. If there is no overloading, possibly it can work.”

Can we use batteries to fill the gaps?

Renewable advocates say that the answer to the supply-matching-demand problem already exists. The electricity simply needs to be stored at times when renewables overproduce to be used at times when they underproduce.

Prof. Schwarz’s answer - this works in principle. But the discrepancy between what is needed and what we have is enormous.

“The question is - what is the size of storage you need, what is the size you have, and how long will it take to expand existing storage to the needed capacity? If you take the real situation, we have a storage capacity of 40 GWh, that’s enough to cover 30 to 60 minutes… (But) If you want to supply Germany for a week when you have ‘dark doldrums’ you need about 5,000 GWh. Existing storage capacity is far away from what you need to supply Germany for a few days.”

He goes on:

Storage capacity on the gas side is 250,000 GWh. Now you get a feeling for this 40 GWh on the one hand and 250,000 on the other. With gas there is no need to match supply and demand, you can store up in the summer for higher demand in the winter. (That’s) absolutely easy to operate. On electricity side we have to do it minute for minute. But normally if you talk to politicians or the media they are not interested in that. They dream about their green future.”

What would happen in the event of a blackout?

Prof Schwarz:

“There was a really good study made for the German parliament in 2011 on the impact of a large and long-term blackout. They investigated only day one. Imagine you have a flat on floor ten of a building. Within one second you have no lights, no heating because there is no electricity for the pumps, no refrigerator, no water because pumps in the water works need electricity. You cant flush the toilet. And now image you stay there for three days… If you want to go to shopping centre, it’s closed because there are no lights, no check-out machines. Cash machines don’t work. If you want to go to hospital, normally they should have a generator but they are only designed to operate the intensive care station… Whenever you have such a blackout, if it’s for a few hours it is not a problem. If you have 24 hours it becomes more and more critical. If you have more than one day it is very horrible.”

Why is no one talking about this?

Dr Schwarz says that the German public has become increasingly naive in recent decades.

“The main problem with the public discussion is that they hear about any new solution and then they think that the problem is solved. If you take the upscaling factor - at university we make some nice research that is normally in the range of one kilowatt. But now we need to get from one kilowatt to one gigawatt - that’s a factor of one million. And for sure you can’t upscale this one million in one step. Upscaling of a factor of 30 to 50 is realistic in one step due to failures in modelling. That means from one kilowatt to one gigawatt takes four steps, and for sure you need five to ten years per step. From new idea to the real system you need 20 to 30 years. People have no idea of the time and money it takes to reach national scaling.”

At the same time, people with no background in engineering dominate the public debate.

“Non-engineers are good at spreading their ideas on social media. They have no technical knowledge of how to do it, but they are always present in the media. As an example, there was a very small protest in Potsdam, (where) a few hundred people demonstrated for renewables. One person with no knowledge claimed that we have enough renewables to create a secure electricity supply. His comments were repeated every 30 minutes on public radio. If you hear it enough you will believe it. A lot of people in Germany think we can do this because they hear nothing else. In China you would call this ‘brainwashing.’”

What are politicians doing about this?

Schwarz complains that short-termism has ruined that sensible plan that was set out at the start of the Energiewende.

“If we go back to the year 2000 there was a clear idea of what to do. The idea was to keep existing nuclear (reactors) as long as possible simply to have reliable and secured output; keep coal-fired units as long as possible and develop carbon capture so that we can run these units as long as possible CO2 free… Then came Fukushima and they became crazy and said let’s move out of nuclear in a very fast track, followed by let’s move out of coal…. Normally you move to the new system when it’s ready and not when it’s still an idea. It is absolutely crazy to to switch off the existing system before the new system is completely running and that’s what they are trying to do in Germany.”

Politicians are too focused on narrow, self-defeating climate goals, he adds:

“There is no engineer in Germany who will argue against the need to reduce CO2, but you can’t explain to the government that our share of global emissions is about 2 percent. If Germany would disappear it would not make a difference. The only thing we an do is develop technology that is cheap and reliable and exportable, so that other countries can use these ideas and we can get more (emissions) reduction. But we want to create our own solutions that are horribly expensive and non-exportable. If you want to do that, you spend huge amounts of money, you help industry to leave Germany, and in the end there is no impact on CO2 reduction.”

Are we headed for trouble?

Prof Schwarz doesn’t seem too optimistic:

“We need a trigger event which is hopefully not too painful that will make people switch on their brains and remember that there is technology that you need. And if we recognize that you have to go back to this we then we will need 10 to 20 years to get back on track.”

“You can talk to people as long as you want. The normal answer is: ‘Professor Schwarz, you have been talking the same bullshit for the past 20 years, but you see the system works, so what is the problem?’ We will see what the situation is in the coming winter. Maybe it will help us to come back to an engineering based solution.”

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Best,

Jörg