Home to nearly half of the world’s population, cities account for more than 70% of global energy-related CO2 emissions and an estimated 50% of global waste. With a rising share of the global population expected to live in urban areas in the coming decades, cities are rallying to become more ecologically responsible and enact policies around sustainability. However, they are now met with another challenge that may further impact the environment: the rollout of 5G connectivity.
Because of its shorter wavelength, 5G demands installations at approximately every 800’ to 1000’ to provide uninterrupted connectivity for both the User Equipment (UE) and IoT devices. While many of the new installations will use existing towers and other infrastructure, the need for densification in small cell installments still calls for an enormous number of new towers. This may not seem like it would have a significant environmental impact, but consider materials used, the installation process, and tower replacement over time.
Installation of traditional steel towers typically takes 1.5 days or longer. During this time, traffic is either idling or being re-routed, adding to greenhouse gas production. Noise pollution is also an issue during these times. The average lifespan of a steel tower is 15-30 years, depending on the natural environment and how the tower is finished. Replacement of corroded towers creates an ongoing problem.
Corroded steel can be recycled, but it is not always feasible—especially when other components such as plastic laminates or paint are present. The process takes time and uses energy. In the recycling process for steel, the material is shredded and then melted to create new sheets of metal. If the rust is simply melted, it will re-form once the metal cools. That’s why the recycling process also includes purification, where elements are added to bond with the oxygen to free the iron from impurities.
The use of steel is itself problematic. The weight of steel towers—approximately 1500 lbs for a 30’ tower—impacts the environment through carbon emissions during shipping. On average, 1.83 tons of CO2 is emitted for every ton of steel produced making steel production a major contributor to global warming adding over 3.3 million tons annually to global emissions. The sizable weight of those towers will typically involve more substantial foundation-work (new or deeper concrete caissons, etc.) which requires emission-heavy concrete and pump trucks as well.
From an environmental standpoint, steel typically comes from opencast mines which use blasting as the primary means of extraction. Opencast mines affect water quality by contaminating groundwater sources, polluting surface water bodies through the processing of raw ore, the mines’ dewatering processes, and waste generated through the process life cycle. It also results in a significant amount of dust which often brings with it serious health impacts such as eye and lung problems.
Alternately, the use of wooden towers (most commonly Western Red Cedar, Douglas Fir, and Southern Pine), presents its own problems to the environment. From Oregon through western Canada, Western Red Cedar (Thuja plicata, WRC) has been dying in areas where it should be thriving. The cause for this sometimes sudden and expanding dieback is currently unknown. The predominant theory for sudden mortality is that trees may be impacted by a changing climate, including increasing average temperatures and drought stress in the form of reduced and inconsistent precipitation. Both the Douglas Fir and Southern Pine with their deep tap-roots and soil-sustaining root systems are vital to forest ecosystems.
Once trees are harvested for use as towers, new dangers are introduced. Wooden utility towers are often treated with pentachlorophenol (or PCP) to protect them against fungi and termites. Copper, chromium, arsenic, as well as creosote, are also used. Exposure to PCP and other preservative chemicals can cause reproductive and developmental problems, damage to the immune system, and even cancer.
Since towers will be installed not only in downtown areas but neighborhoods as well, it is important to note that children and developing fetuses are most at risk. As early as the 1990s, the EPA calculated that children face a 220 times increased risk of cancer from exposure to soil contaminated with PCP leaching out of the utility towers. The chemical is also highly toxic to birds, mammals, and aquatic organisms as well as other urban fauna. The EPA notes that even a relatively short exposure (as little as 6 hours) can result in mortality of fish eggs occurring as much as 80 days later.
Cement is used to secure both steel and wood towers. Taking in all stages of production, concrete is said to be responsible for 4.8% of the world’s CO2. Among materials, only coal, oil and gas are a greater source of greenhouse gases.
EasyStreet Systems Approach
Components of the EasyStreet tower solutions—composites such as carbon and glass fibers and polyurea coating—are environmentally friendly. Because it is lightweight, the tower is easily secured using quick-drying, sustainable high-performance polyurethane
Polyurea is a solvent-free, two-component material. It is highly resistant to a large number of chemicals, acids, and alkalis to which both steel and aluminum are susceptible. Moreover, polyurea releases neither CO2 nor other harmful gases during its manufacture or lifetime. When cured, polyurea is permanently waterproof, durable, and therefore sustainable and reusable.
Although the manufacture of composites can be energy-intensive, the products are not susceptible to corrosion, degradation, rust or fatigue; therefore, it potentially only has to be produced once, where a steel tower would have to be replaced multiple times.
Because it is made from glass, fiberglass withstands temperatures at 40 degrees below zero and over 350 degrees. Moreover, fiberglass is strong and requires no maintenance. It holds steady in winds up to 200 miles per hour. It is not prone to moisture, and it will not be impacted by UV rays.
Production of fiberglass does not require a lot of energy, and it is lightweight and easy to transport. This keeps costs and consumption to a minimum. Moreover, fiberglass is sourced almost entirely from sand, a natural resource that can be found across the planet in great supply. Fiberglass is durable and efficient, which is why it has earned an Energy Star rating. It can be used in conjunction with LEED and Green Global ratings.
Ultimately, since fiberglass lasts for decades or more, it will not be replaced often. This longevity is an important factor in its potential sustainability.
Like fiberglass, carbon fiber doesn’t corrode, degrade, rust or fatigue. That means it has a much longer lifecycle, so it potentially only has to be produced once where a steel part would have to be replaced multiple times. Weight is an important element in determining the amount of fuel used in transportation. Both glass and carbon fiber make for a lightweight load— about75-80 percent less than steel— which means fewer emissions.
These composites need no additional resources for maintenance and can be reclaimed and reused when recycled. Further, their light weight means that a small crew of 2-3 workers are needed to install an equivalent 30’ high 150-lb EasyStreet tower. Workers use primarily hand tools meaning minimal noise pollution. Installation takes hours rather than days which facilitates smoother traffic flow and cuts down emissions from idling vehicles.
Minimizing foundation work also has dramatic emissions savings over traditional methods. Unlike steel and wood towers which are stabilized using cement, fast-drying polyurethane foam--which has a negligible environmental impact--can be used to set the towers in place.
Clearly, EasyStreet System's combination of lightweight, sustainable products offers cities an important opportunity to move forward responsibly as they implement their 5-G connectivity goals..
For Further Reading
Is Carbon Fiber Better for the Environment than Steel?
Composites and sustainability – when green becomes golden
Composites vs. Other Materials in Industrial Applications
Carbon Fiber Reinforced Thermoset Composite with Near 100% Recyclability
Identification of Key Sustainability Performance Indicators and related assessment methods for the carbon fiber recycling sector
Sustainability assessment of solvolysis using supercritical fluids for carbon fiber reinforced polymers waste management
Life Cycle Engineering of Carbon Fibres for Lightweight Structures
Do Fiber-Reinforced Polymer Composites Provide Environmentally Benign Alternatives? A Life-Cycle-Assessment-Based Study
Environmental Concerns Expected to Help Spur Strong Demand for Polyurea Coatings
Fiberglass Green and Sustainability
Is Fiberglass Recyclable?
You Really Shouldn’t Touch Those Wooden Utility Poles: Millions of these poles continue to be coated with PCP, a carcinogenic chemical
Mitigating the environmental effects of opencast mining
Environmental impact of steel production
Concrete: the most destructive material on Earth
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