Happy Earth Day!
Aradatum is a startup based in Brighton, Michigan, that is designing a cell tower than could be placed in remote locations and run on renewable energy without having to connect to the electric grid.
Its 150-foot tower integrates a vertical-axis wind turbine and solar panels. Vanadium flow battery storage provides a consistent supply of DC power. And each tower site will also include a generator to ensure power if the battery ever gets too low.
Aradatum President Larry Leete said, “We know that carriers are driving to net-zero solutions. But there’s no infrastructure to do that.”
In fact, most carriers, such as Verizon, have Environmental, Social and corporate Governance (ESG) policies and periodically talk about their energy-efficiency initiatives as well as their strategies to make their networks resilient in the face of climate change.
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For his part, Leete is passionate about renewable energy. He points out that the energy grid was designed more than a century ago to turn on lights and refrigerate food. Over the years, it’s been tapped to power almost everything required for modern life. When there are brownouts or blackouts, everything can go down, including telecommunications networks. He thinks it makes more sense to have at least some of the telecom ecosystem reliant on more distributed and independent energy sources, rather than a centralized grid.
Leete also thinks his company can fill a need for telecom towers in hard-to-reach locales and rough terrain. It’s currently in conversations with the wireless internet service providers (WISPs) Redzone Wireless in Maine and Resound Networks in Texas.
RELATED: Resound trades fiber for fixed wireless for a chunk of its RDOF builds
Aradatum, which has raised $15 million, is planning pilot projects in Michigan, Kansas and Maine. And it expects to have built four towers for those trials by March 2023.
Leete considers Aradatum a tower company, but not one that would compete against the big guys: Crown Castle, SBA Communications or American Tower. “I’m not competing with them at all,” he said. “We’re complementary, looking to go into those areas they can’t; going to places where the only option was previously satellite.”
WISPA looks at renewables
Richard Bernhardt is the National Spectrum Advisor for the Wireless Internet Service Provider's Association (WISPA). He’s helping WISPA work on a suite of best practices for climate resilience.
He said the amount of power needed at a site varies greatly depending on what the radio does and how much power it puts out. Many WISPS do fixed wireless access (FWA) that provides home broadband services, but not mobile cellular service.
For that type of FWA, “the power is much, much less than the telecom cellular tower that uses a macro,” said Bernhardt. “In mobile the idea is to do coverage. When you walk around with cell phones, you go from tower to tower in this umbrella of signal, and you don’t want that signal to disconnect. In point-to-point, where you’re taking it to your house or company, the signal or energy, only has to go to a single point. You can imagine the kind of energy you need to power a tower for fixed wireless is very different from a macro that a telecom provider uses. One will use 50 watts and the other maybe 16,000 watts.”
He said to do renewables at the macro level, carriers will need locations “where green-type energy is really consistent and abundant.”
But he agrees with Leete that using alternative energy allows for greater resilience in networks. And Bernhardt said, “There are places so remote that using grid-base electricity is unfeasible; there may not be power available. You have to come up with creative ways to power.”
Backhaul
The big carriers often use fiber for backhaul from their towers. So, it would seem that if they’re already having to trench for fiber, they could also supply electricity from the power grid. But both Leete and Bernhardt said fiber often isn’t used for backhaul in remote areas. Microwave is the technology of choice in those places.
“Backhaul does not require fiber,” said Bernhardt. “It can work fine on RF and microwave.” He said operators often “set up a relay of radios back-to-back.” They install towers every several miles and then put radios on each tower with one facing backward and one facing forward. “It cuts it for cellular providers all over the country,” he said.
In the case of microwave repeaters, a smaller amount of power is required, and renewables could be an option.
Small Cells
Bernhardt also pointed out that cellular networks are comprised of not just macro towers but also lots of small cells. “Distributed 5G is mostly small cells,” he said. “That small cell doesn’t require anywhere as much power as a macro. A small cell is only dealing with the distance between it and the next small cell.”
He said those cells are often energized with municipal power, but solar would be a reasonable option in many places as long as there is consistent power for a certain amount of time. In the case of solar it requires about 6-8 hours of sun exposure per day to generate enough power to charge the batteries.
Tycon Systems, which is a member of WISPA, is a company that provides renewable energy solutions for rural locations.
Scott Parsons, CEO at Tycon Systems, said, “The scale of our products is smaller and lower cost that what it would take to power a normal cell tower. The maximum we can power right now is about 300 watts continuous power with our largest system. Typical cell towers require more power than that.”
But Tycon Systems does provide some WISPS with the power systems for their microwave backhaul.
Parsons said, “We handle some base stations, and those are the ones that might have six radios, four cameras and some other sensors.” He said some of those telecom customers also supply a back-up generator, and Tycon’s technology can automatically turn on the generator if the renewable power is running too low.
Getting back to Earth Day, Bernhardt said WISPA is a big proponent of using the right technology for the situation at hand, and in terms of power, it’s a good idea to decentralize some telecom infrastructure. “In these days where fierce weather events are happening, it behooves us to think about decentralized approaches.”