Too Much of a Good Thing Solar Overloads Europe's Electricity System
When the official report on the Spain and Portugal blackout from April came out, it described a grid made vulnerable to excess voltage as a result of the fast growth of weather-dependent generators. But this excess voltage problem is not just reserved for the Iberian Peninsula. The whole of Europe has become vulnerable.
Last year, a total of 65.5 GW of solar generation capacity was installed across the European Union. It was a record high, and the fourth record-high year of installations in a row, as reported by the EU’s solar power industry association. However, the annual growth rate in additions was markedly lower than in previous years, at just 4.4%, Solar Power Europe noted. Since the start of this year, things have only got worse, with total new installations expected to be a decline on 2024 rather than an increase. It would be the first decline in ten years.
Solar is one of the pillars on which the European Union’s transition plans are built. Solar, along with wind, is instrumental for what Brussels strategists call a decarbonisation of the European grid. However, there have been unforeseen circumstances that have interfered with these plans and are going to interfere with them increasingly frequently because of the nature of solar, affecting growth plans.
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One obvious problem that was not anticipated is negative prices. The phenomenon, sometimes called a cannibalization effect, refers to periods of excessive generation from wind and/or solar that plunges electricity prices on the wholesale market below zero because supply exceeds demand by a very wide margin.
In Europe, the problem has become especially pronounced in the past couple of years, thanks to all those record solar capacity additions—and it has started affecting investment decisions for further capacity because negative prices affect the profitability of existing installations. Some governments have considered support for solar operators forced to switch off their installations when there is excess generation, but not all.
Switching off a solar installation is what grid operators order whenever generation threatens to become excessive. This is also problematic for solar operators, because when their installations do not generate electricity, the operators do not make money. Sure, they can be paid to not generate, like wind turbine operators in the UK, but that does not necessarily guarantee profits—government handouts never do.
Finally, there is the voltage surge problem that caused the Spain and Portugal blackout, and that Bloomberg this week reported is getting more serious across Europe. The solution proposed: change the grid.
The argument that Europe’s grid is not fit for a decarbonized energy system has been put forward repeatedly by transition advocates who claim we need a more flexible electricity supply and distribution network that would reduce—and maybe even eliminate—the waste of electricity generated by wind and solar installations during periods of low demand. Flexibility, including on the demand side, is being made a top priority. The problem is that solar is not very flexible. When the sun shines, the panels generate, regardless of demand. When the sun stops shining, the panels stop generating, also regardless of demand.
According to one Dutch grid expert who Bloomberg interviewed, the problem is one of scale. There are simply way too many solar installations to control all at the same time and make sure the grid does not get overloaded on sunny days. “The speed of the change is extreme,” Jan Vorrink, who was in charge of the control room of the Netherland’s grid, told Bloomberg. “The strong increase in solar is pushing the boundaries of the system.”
Obviously, the simplest solution would be to put caps on solar capacity additions to make the grid more manageable. Yet this is not the preferred solution in Europe. The preferred solution is to continue building more installations and transform the grid to be better able to incorporate these installations productively.
The transformation would essentially involve building a lot more transmission lines to bring electricity from generators to demand hotspots to reduce curtailment. This would include better interconnectivity between EU member states to tap into cross-border electricity demand. However, this would not do much about the voltage surge risk. Demand patterns tend to be pretty consistent across countries—and they do not always coincide with peak solar generation, which is what creates the voltage surge risk.
Last year, there were 8,645 voltage surges in Europe, per data from ENTSO-E, the EU grid operators’ association. The figure represents a 2,000% increase from 2015, when there were 34 surges. This is not going to change in a safer direction anytime soon, even if the EU stays on its chosen grid transformation path. Such a transformation takes a lot of time—and money—and in the meantime, the grid will remain highly vulnerable to power outages resulting from voltage surges caused by excess solar generation that cannot be brought down fast enough when demand dips. Maybe exercises in flexibility need to touch on the generation part of the electricity equation.
By Irina Slav for Oilprice.com
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