May 1, 2023

The European electricity grid is getting increasingly overloaded

An influx of new sustainable energy sources is testing the limits of the European electricity grid. This is leading to ever stranger situations to get rid of excess power, like throwing the lights on in empty greenhouses.

"Help, it's getting sunny again!"

Due to an excess inflow of renewable energy, European grid operators are increasingly forced to take emergency measures to stabilize the grid. Especially around sunny peaks and lazy hours, when there is an abundance of clean and cheap power flowing onto the grid, operators are trying to get rid of solar power they don’t have any better use for. And it's only spring, and the sun isn’t even at its highest point on the Northern Hemisphere yet.

Last Easter, in early April 2023, the situation started becoming pretty unique. So much solar energy flowed onto the grid, while so many people were out and about doing Eastery things, that grid operators desperately sought ways to burn off the generated electricity because no one was there to use it. 

So in Dutch greenhouses, lights were turned on in broad daylight to get rid of the excess solar energy. Water was pumped from one lake to another, without any other clear purpose but to use up power. French nuclear power plants disconnected the turbines from their generators as to not flow more energy onto the grid. And all over Europe, solar installations were decoupled from the grid as to not overload it more.

These emergency measures are -obviously- not a great way to deal with our power, as it's very wasteful. 

First, the good news 

The good news is of course that solar energy is doing very well currently, and shows no sign of stopping. According to a report from industry group SolarPower Europe, solar power installation soared by almost 50 percent in Europe in 2022. The EU installed a record-breaking 41.4 GW of solar this year - a 47 per cent increase from the 28.1 GW installed in 2021.

The Netherlands is currently leading the pack, with about 1kW installed per person, making it the highest per-capita country in Europe. After a slow start in the previous decade, the Netherlands has installed a large number of solar panels especially since 2018. As of April 2023, about 20 gigawatts of peak capacity has been installed, with an annual growth of about 4 gigawatts, a 20%. And this excludes wind energy.

Emergency messages on the feed of Dutch grid operator Tennet, which is warning that it's using its 'incident reserve' to stabilize the grid. This is happening more often on sunny, windy and quiet days.

Stability and flexibility

Solar and wind energy still account for a small portion of the Netherlands' total energy demand. But because of their increased scale and the unpredictability of these sustainable sources, a lot of flexibility is needed on the grid.


  1. The electricity grid always needs to be in an almost perfect balance. The exact amount of energy flowing on to the grid has to be pretty much equal to the amount of power that’s consumed. If not, voltages will rise, the grid will heat up, and parts might start saying ‘boom’ eventually.
  2. Sunshine and wind are unpredictable sources that can surge in minutes, because of clouds disappearing or the wind picking up. To balance this volatility, flexible solutions are needed to add or pull power from the grid.

Usually, careful planning and estimating power use helps to keep the grid stable. But now, during peak solar output, grid operators have to find new ways to use the excess power - such as turning the lights on in greenhouses during a sunny day. Sometimes under plants that don’t need the extra light or sometimes even in empty greenhouses!

This is all good business for greenhouse owners who get paid to consume electricity - and often even have a generator which can also help to supply flexible power to the grid. But these are all emergency measures, in place because we're lagging behind in upgrading our grid compared to the renewable energy we're scaling up.

Emergency measures

In the Netherlands, grid operator Tennet has increasingly reported incidents to their market parties, asking for power to be consumed as quickly as possible due to a power surplus. Market parties can then step in to stabilize the grid.

"This situation is quite unique," says Stekker’s energy expert Erik van Boekel. "We really need a much more flexible and sustainable approach to handle situations like we saw during Easter."

In other words, when there's too much solar energy on the grid, we need to store it intelligently so we can use it later. (Like in electric vehicles)

Sometimes, emergency measures in the opposite direction are necessary. When it's suddenly less sunny than expected, or the wind dies down, the grid must not become "underfed." Power needs to be produced quickly when the wind stops blowing and the sun hides behind clouds.

One method grid operators have is to ask for more production from large power plants, but this is slow and inflexible. That's why emergency measures have been devised, such as using combined heat and power (CHP) units in greenhouses.

These individual CHP units may be small, but together they account for nearly 1000 megawatts (1 GWh) of power production. Through intermediaries like Powerhouse, much of this capacity can be flexibly accessed when the grid needs more power.

"This problem affects the whole of Europe," says Erik van Boekel. "Solar panels shut down, or grid operators have to find somewhere to put their energy. Grid operators are trying to intervene wherever possible, but they need more tools in their toolbox to stabilize the grid."

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