Generally, generating facilities were not as badly damaged as the transmission and distribution system (Table 15) (U.S. Energy Information Administration 2018). Most renewable generating facilities sustained modest amounts of damage (see Table 15); however, none of these facilities were able to connect to the power grid for several months (U.S. Energy Information Administration 2018). Small amounts of solar and hydropower were able to reconnect to the transmission system in late 2017; however, the first wind farm reconnected in February 2018 (U.S. Energy Information Administration 2018). Puerto Rico’s second largest solar farm and second largest wind farm were both badly damaged and are not expected to be in service until 2019 (U.S. Energy Information Administration 2018).

# **4.1 - Power Generation**

While Puerto Rico has some renewable solar, wind, and hydropower resources, the island has no reserves or production of conventional fossil fuels and primarily relies on imported fossil fuels (U.S. Energy Information Administration 2018). Approximately three-fourths of the energy used in Puerto Rico comes from petroleum products, most of which are imported through the ports of San Juan, Guayanilla, and Ponce (U.S. Energy Information Administration 2018). These ports were closed for 5 to 14 days following Hurricane Maria, leading to an estimated loss of 1.2 million barrels of petroleum per day during this period (U.S. Department of Energy 2018a).

# **Solar**

The experience of Puerto Rico’s solar farms in the aftermath of Hurricane Maria exemplify the importance of understanding the intra-system interdependencies and role that resilient designs can play in the vulnerability of systems. The extent of damages to transmission infrastructure was the primary driver of electricity recovery in Puerto Rico; specifically, different solar energy farms proved to have different levels of resilience during the 2017 Hurricane season in the Caribbean. While Hurricane Maria’s flooding rains and winds heavily damaged a few of Puerto Rico’s solar farms, including the second largest solar farm on the island where a majority of recently added solar panels were ripped from their foundations, many sites sustained minimal to no damage, Table 16 (Smith, 2017). The Illumina solar farm located on the southern coast is estimated to have lost a quarter of the modules from the 24 MW system to the storm (Limperis 2017). In contrast, there were hardly any damages to systems with adaptive designs (Limperis 2017). The solar farm in Loiza on the northern coast remained almost untouched by the hurricane (Limperis 2017). The panels at the site were specifically designed to outlast hurricanes: to prevent flood damage, each panel was built at least 2-meters off the ground and reinforced to withstand winds of Category 5 hurricanes (approximately 251 kph) (Smith 2017).

While a majority of solar farms sustained very little damage, a major factor preventing solar farms from exporting power to the grid was the complete destruction of the transmission and distribution system. This prevented sites from being able to reconnect to the grid and operate at full capacity. Apart from some torn away modules, Pattern Energy’s 101 MW Santa Isabel wind farm sustained minimal damage following the storm (Limperis 2017). While the farm lost power in the days following Hurricane Maria’s landfall, within a week, the farm informed Puerto Rico’s Electric Power Authority (PREPA) that it was ready to return to normal operations (Merchant 2018). However, over seven months after Hurricane Maria, generation remained 75 percent curtailed because of grid issues (Merchant 2018). Similarly, AES’ Illumina solar farm also was curtailed for months due to transmission work delays (Merchant 2018). Further, PREPA did not authorize the 24 MW solar farm in Guyama to begin exporting power to the grid until February 2018, and then only at 10% of the farms’ normal generation. Of particular concern was that solar power could create instability with the recovering transmission network in the area not able to support the amount of electricity potentially being fed into it (Gallucci 2018). Over a year after the storm, in October 2018, the site was only operating at 74 percent capacity (Gallucci 2018).

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