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Today in Energy

June 24, 2020

Puerto Rico’s electricity generation mix changed following early 2020 earthquakes

Puerto Rico monthly net electricity generation by fuel type
Source: U.S. Energy Information Administration, Form EIA-923M, Power Plant Operations Report, data for 2019 and 2020 are preliminary

According to data from the U.S. Energy Information Administration’s (EIA) latest Power Plant Operations Report, electricity generation in Puerto Rico has shifted toward heavier reliance on petroleum following two earthquakes that struck 9 miles off the southwest coast of Puerto Rico earlier this year.

On January 6, 2020, a magnitude 5.4 earthquake hit Puerto Rico, followed by a magnitude 6.4 earthquake on January 7. The epicenters of these earthquakes were not far from two of Puerto Rico’s largest power plants, Costa Sur and EcoEléctrica, both of which primarily use natural gas for electricity generation. The earthquakes caused widespread power outages, and approximately 900,000 of Puerto Rico's 1.5 million customers lost power. The earthquakes significantly damaged the Costa Sur plant, knocking it offline indefinitely.

Although recovery efforts restored electrical service to about 99% of customers by January 13, monthly power generation on the island was 17% lower in January 2020 than it was in December 2019 because of the outages. In February and March, generation recovered to levels typical for that time of year.

Before the earthquakes, Costa Sur was the largest power plant in Puerto Rico, with 967 megawatts (MW) of net summer capacity that generated 21% of the island’s power and represented 52% of its natural gas-fired electricity generation. The loss of the Costa Sur plant, as well as reduced generation from the natural gas-fired EcoEléctrica plant, shifted Puerto Rico’s power supply to predominantly petroleum-based generation.

In the first three months of 2020, petroleum accounted for 60% of generation, compared with 38% in 2019. Natural gas-fired generation, meanwhile, has fallen to 17% of total generation compared with 41% in 2019. Coal, renewables, and other generation sources have largely maintained the same shares.

Puerto Rico monthly net electricity generation by plant
Source: U.S. Energy Information Administration, Form EIA-923M, Power Plant Operations Report, data for 2019 and 2020 are preliminary

The shift to a larger share of petroleum-fired electricity generation in Puerto Rico is apparent at the plant level. With the Costa Sur plant offline, Puerto Rico’s five petroleum-fired plants have increased generation to meet demand. Electricity generation from the Palo Seco petroleum-fired plant has more than doubled, and the petroleum-fired Aguirre and Central San Juan plants have increased their monthly average generation by 8% and 10%, respectively.

In addition, two petroleum plants that normally only serve peak load and generally run at low average monthly levels in the winter and spring months, Cambalache and Mayagüez, significantly increased their generation in the first three months of 2020. Cambalache’s monthly average has grown from 12,000 megawatthours (MWh) per month in 2019 to 40,000 MWh per month through March 2020; Mayagüez increased from an average of 8,000 MWh to 20,000 MWh per month in the same time period.

The Puerto Rico Electric Power Authority (PREPA) is still assessing the extent of the damages to the Costa Sur plant. In the interim, PREPA has issued requests for proposals for up to 500 MW of mobile temporary capacity, about half of the capacity of the offline Costa Sur plant, to meet the electricity demand of summer peak season.

Principal contributor: Paul McArdle