12. THE RESILIENCE OF US ENERGY INFRASTRUCTURE
develop grid technologies that are better suited to changes in the power mix, especially the integration of larger shares of variable renewable generation.
One of the lessons learned from past electricity blackouts relates to the role that decentralised renewable energy can play to improve resilience by expanding flexibility in the power system through diversification of resources and technologies.
Resilience in oil and gas infrastructure
Resilience options for the oil and gas sectors depend heavily on the threats facing critical energy infrastructure (see also Emergency Response section in Chapter 7, “Oil” and Chapter 8, “Natural Gas”).
Upstream
In 2005, Hurricanes Katrina and Rita inflicted significant damage on Gulf Coast wells and refineries, destroying 115 offshore platforms and damaging 52 others, damaging 535 pipeline segments, and causing a near total shutdown of the Gulf's offshore oil and gas production for several weeks. A more recent example was Hurricane Harvey, which made landfall in late August 2017 as a Category 4 hurricane, making it the strongest storm to strike Texas since 1961. The hurricane had severe impacts on onshore and offshore production and caused dramatic flooding in Houston. Logistical issues ranging from diesel shortages to difficulties getting sand to well sites for hydraulic fracturing operations delayed return to normal operations for several weeks (see also chapters 7 and 8).
Downstream
Hurricane rains and flooding can also cause extensive damage to refineries, and normally result in extended recovery times. The hurricanes of 2005 and 2008 caused extensive water damage to refinery control systems, electrical equipment and pump motors, and caused storage tanks to move off their foundations. In response, government and industry have built common flood protection structures such as flood walls. In response to extensive water damage, many refineries have also elevated substations, control rooms and pump stations above the likely flood level. In many cases, facilities have been elevated 15 feet to 25 feet above ground level.
A number of refineries have invested in portable generators, but the majority of facilities have instead established plans that enable them to quickly lease generators in advance of an approaching hurricane. Even the largest mobile generators, however, cannot provide sufficient electricity supply to operate a refinery. Refiners rely on portable generators only to provide critical service (the data control centre, critical information and technology facilities, and the water pumps) or safely shut down operations until grid power can be restored. Winds of hurricane strength can cause severe damage to refineries, and their cooling towers are especially susceptible to wind damage. High winds can cause the fan blades inside a cooling tower to become dislodged and launched from the tower if they are not properly secured. Several refiners have installed special braces to stop the fan blades from dislodging.
As a more recent example, in August 2017, Hurricane Harvey also affected US LNG exports; the Sabine Pass terminal stopped loading LNG vessels for 12 days. In the
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