11 Mar 2024 | 09:54 UTC

Spanish nuclear output halves after three plants halt

Highlights

Almaraz 1, Cofrentes halted due to strong renewables

Asco 1 suffers water supply fault

Day-ahead price rebounds from near zero

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Spanish nuclear output has been reduced to about half over the weekend as three of seven plants were taken offline, grid data showed March 11.

Nuclear output is seen at a steady 3.6 GW through March 11, down from typical output of 7.1 GW when all seven reactors are running normally, according to Red Electrica de Espana (REE).

The Iberdrola majority-owned Almaraz 1 with 1.05 GW capacity went offline on March 8, and is expected restart March 18, according to transparency data from Entso-e.

Operator CNAT said in a statement the halt was due to increased renewable generation and noted that the plant was on standby without any issues. The plant is due a refueling halt in September, while its sister plant Almaraz 2 is due to undergo refueling in April.

Iberdrola-owned Cofrentes, Spain's largest nuclear plant with 1.09 GW capacity, was then taken offline early March 9. The plant is due to return March 16, according to EntsoE. Operator CN Cofrentes also attributed the halt to "prolonged renewable output."

In the evening of March 9, a fault with the water supply to a generator at the Endesa-owned 1.02-GW Asco 1 took the unit offline automatically, operator ANAV said. The unit is due to return March 12, according to Entso-e.

The plant had already suffered issues earlier this month, causing it to ramp down capacity between March 2 and March 5. Its next programmed refueling halt is in November.

Prior to the three halts, Spanish reactors had generally been running at trimmed rates as strong wind power production ousted nuclear from the supply mix amid seasonally muted demand.

A fourth plant, Iberdrola's 1.07 GW Trillo, has run at around two-thirds of capacity since Feb. 22. Trillo is due to refuel in May, according to Entso-e.

Spain's day-ahead power price rose to Eur14.63/MWh for March 11 delivery, from just Eur0.59/MWh March 9 and Eur0.54/MWh March 10.

Wind output is forecast to reach 249 GWh March 11, with hydro at 156 GWh and solar at 125 GWh, meeting 79% of domestic demand, REE estimates.