The Extra Mile On Industrial Performance
The Extra Mile On Industrial Performance
The Spanish Blackout
In Spain, there are 3 main levels of voltage in the grid (220KV or more, between 110KV and 220KV, and lower then 110KV). The Grid Operator, named Red Eléctrica (REE), is at the same time the TSO of the high voltage grid (>220KV). Only the backbone network consists of:
- +45,000 kilometers of high-voltage lines (440 KV + 220KV)
- 700 substations
- 6,000 high-voltage towers
- +225 transformers
On the 28th of April at 12:33 pm, a full blackout for Power and Telecom in Spain and Portugal happened. Only those with old transistors kept informed. On 12th of June, there is no official report yet, and the Truth could suffer as REE is controlled by the Spanish Government and the multi-million euro liabilities from claims.
Let’s focus first on the facts:
1. Total installed capacity is nearly 130 GW, with Solar + Wind accounting for more than 50%.
2. The peak demand is between 25 GW and 40 GW, depending on the season.
3. Portugal + Spain forms the Iberian Peninsula, which is considered an energy island, because the interconnections with the European Network through France are very limited (<4% of the generation goes through the interconnection, although the EU recommends +10%)
4. Battery Energy Storage is still nearly null in Spain, although there is an ambitious plan to escalate.
5. Inverter-based Wind and Solar generation were 70% of the mix just before the blackout.
6. In that moment, only 6 combined cycles with a total capacity of 3.6 GW, but producing at 40%, were operating. That means 5% of the total CCGT capacity (26.3 GW).
7. From the 7 nuclear power blocks, only 4 nuclear groups were dispatched, producing at 93% of their capacity.
8. 13 solar parks (of more than 100 MW) with a total generation of around 2.7 GW, operating at an average of 68% of their cumulative nominal capacity (4 GW).
9. The Spanish government pointed to the 2.2 GW of solar energy that fell first and caused the snowball effect as the original cause of the blackout, with 1.3 GW belonging to plants with a capacity of less than 100 MW. Assuming an average capacity of 50 MW per plant and an equivalent generation at that time of 68%, this would mean that another 38 solar plants had to be disconnected between the pointed three provinces separated by hundreds of kilometers.
So, what is the most reasonable root cause?
All the possibilities are still open, even a potential cyber attack in small solar plants or small control centers in the lowest voltage distribution network.
However, the most reasonable cause is the alignment of trip conditions: we realized that for the plants of less than 50MW connected to the lower voltage levels, are regulated to trip after only ONE SECOND with an overvoltage of 10% of more.
This means that many solar plant could trip at the same time, triggering the snow ball which ended in the blackout.
If confirmed, it would imply that an old regulation (designed when solar and wind did not exist) could be responsible for triggering the blackout.
Could the Grid Operator have done more?
The weeks after the blackout, the REE operated the grid much more conservatively: curtailing more renewables and increasing the percentage of the CCGT generation in the mix. The result was a more expensive electricity, but much more secure.
So the answer to the question should be: to operate with more synchronous CCGTs. They are requested to be very flexible. In Spain, the PLF (Power Load Factor) of the CCGTs is around 12%… It is not only that they have +200 startups per year, it is that when they operate, they operate few hours at minimum load, so their economic sustainability is on risk.
Updating CCGTs to be more flexible seems to be a must today.