Costa Rica’s generating capacity was working close to its limit as April began, in large part because of a lack of water from a particularly dry year that by the end of the dry season had left Costa Rica’s hydroelectric-dependent energy infrastructure with 25% less capacity.
With generators working full time and little room for error, Costa Rica’s electricity grid received its first shock April 3 when one of the country’s largest thermal turbines in the Caribbean port of Moín, with a capacity to generate 40 MW, suddenly stopped working for reasons still under investigation at press time, though ICE workers suspect design flaws may be at fault. ICE engineer Luis Pacheco said it was the last turbine ICE would have expected to falter, since it is only three years old.
The following day, on April 4, a transformer stopped working that led to the shut down of a 34-year-old, 17 MW turbine at a thermal plant in San Antonio de Belén, northwest of San José.
Twelve days later, another turbine at the Moín plant, this one a 16-year-old, 36 MW turbine, stopped functioning. On April 18, the day before the nationwide blackout, a 33-year-old turbine at a thermal plant in Barranca, on the central Pacific coast, went out of operation. ICE scrambled to implement emergency rationing.
That next day, a transformer on Arenal’s substation exploded, causing the loss of 157 MW and leaving the system with less capacity than it requires to keep running, and the nation was plunged into darkness.
ICE officials say the blown circuit is unrelated to the downed turbines. Two of the three turbines and the transformer in the Belén were up and running again this week.
But one of ICE’s newest and largest turbines, the one in Moín, is still offline. ICE is also investigating why the circuit in Arenal’s transmission line exploded.