Solar Streetlights for Chile’s Coastal Fishing Ports and Patagonia Highways: Structural Material Selection Amidst the Dual Challenges of Salt Fog Corrosion and Extreme Winds
Chile’s elongated geographical shape—spanning over 4,300 kilometers from north to south—gives rise to an exceptionally diverse range of climatic conditions. The central region enjoys a temperate Mediterranean climate that is pleasant and comfortable; the north is home to the hyper-arid Atacama Desert; while the southern Patagonia region represents the opposite extreme—one of the most wind-swept inhabited areas on Earth. Here, the average annual wind speed exceeds 10 meters per second, with extreme gusts capable of reaching 50 meters per second (equivalent to 180 km/h)—a velocity that surpasses the maximum design limits stipulated in most standard building codes.
Southern Chile is also dotted with numerous fishing ports (caletas pesqueras) scattered along the Pacific coast. These ports typically consist of small communities characterized by poor grid coverage and severe salt fog corrosion. Solar streetlights represent the ideal lighting solution for such off-grid or weak-grid fishing communities; however, the combined forces of extreme winds and corrosive salt fog impose rigorous demands on the structural integrity and anti-corrosion design of the equipment.
I. Structural Design for Extreme Wind Loads in Patagonia
The wind intensity in Patagonia ranks among the highest of any inhabited region globally. In Punta Arenas, for instance, the average annual wind speed hovers between 9 and 12 meters per second, with recorded extreme gusts exceeding 50 meters per second. In such an environment, standard-specification solar streetlight poles do not merely bend under the wind's force; they are liable to snap outright or be torn completely from their foundations.
To address the specific wind conditions of Patagonia, the structural design of the streetlight poles must adhere to the requirements for the highest wind-speed zones as defined by Chile’s NCh 432 standard (the code governing wind loads on buildings). Key design parameters include: the design wind speed must be based on the local 50-year return period wind speed (approximately 45 to 50 meters per second in the vicinity of Punta Arenas); the outer diameter and wall thickness of the pole base must be engineered to withstand calculated bending moments—dimensions that typically need to be significantly larger than those used in lower-wind regions; and the foundation must be embedded to a minimum depth of 1.5 meters, utilizing an enlarged base plate to enhance its resistance to uplift forces. For integrated solar streetlights, the photovoltaic (PV) panel presents the largest wind-facing surface area; consequently, under the windy conditions characteristic of Patagonia, calculating the design wind loads for the PV panel mounting brackets is of critical importance. Adjustable-tilt PV brackets—which allow the panel to be flattened when extreme winds are forecast—significantly reduce the wind-facing area and are the recommended configuration for high-risk regions.
II. Coastal Salt Spray Corrosion Protection System
The intensity of salt spray corrosion along Chile's Pacific coast varies by region. The central coast (specifically the area surrounding Valparaíso) falls under a C4 corrosion environment classification. The southern coast, characterized by higher rainfall and humidity, presents a more aggressive corrosive environment; areas in close proximity to the shoreline are classified as C5 environments.
The selection of a corrosion protection system must correspond directly to the specific corrosion environment classification. For C4 environments: Hot-dip galvanizing (85 µm) + Epoxy primer (60 µm) + Polyurethane topcoat (60 µm), resulting in a total dry film thickness of approximately 200 µm. For C5 environments: The C4 scheme is augmented with an intermediate coat of micaceous iron oxide (MIO) epoxy (80 µm), bringing the total dry film thickness to over 240 µm; additionally, the topcoat is upgraded to a high-performance aliphatic polyurethane formulated to resist both UV radiation and humid-heat conditions. All fasteners utilized are constructed from 316L stainless steel, and the PV panels are certified to meet the requirements of the IEC 61701 salt mist corrosion test standard.
III. Lighting Characteristics of the Southern Highway (Carretera Austral)
Chile's Southern Highway (Carretera Austral, or Route 7) spans approximately 1,240 kilometers, traversing the lakes, fjords, and rainforests of northern Patagonia. It is renowned as one of Chile's most spectacular roadways and has emerged in recent years as a popular destination for ecotourism. Large sections of the highway lack access to grid electricity; consequently, off-grid solar streetlights represent the only viable lighting solution for key nodes along the route—such as ferry terminals, town entrances, and scenic viewpoints.
Along the Southern Highway, the annual average peak daily sunshine duration is approximately 3 to 4 hours—significantly lower than that of the Atacama region in the north. During the winter months (June through August), this duration drops even further to a mere 1.5 to 2 hours per day, frequently accompanied by prolonged periods of overcast and rainy weather. The system battery capacity shall be calculated based on the month with the lowest daily solar insolation during winter, ensuring an autonomous operation duration of no less than five days to guarantee uninterrupted lighting during periods of continuous overcast or rainy weather.
Post time:Apr - 02 - 2026
