“I’ve probably been involved in power for telecommunications for 20 out of my 30 years in the electric power industry,” Smith began. “What’s fascinating is that as an organisation, we power the entire internet, from the handset all the way to the data centre.”

While much of the industry’s focus has been on hyperscale data centres and megawatt-hungry AI workloads, Smith’s attention is on the other end of the digital revolution: the mobile towers that connect billions across the globe.

“These are the backbone of connectivity,” he said. “There are hundreds of thousands of them around the world, with many in remote, off-grid areas. And every one of them needs reliable power.”

From 2G to 5G: A surge in power demand

The growth of mobile internet usage has triggered an unprecedented rise in tower energy demand. “A 2G tower might use two kilowatts, a 3G tower four,” Smith explained. “But a 5G tower can take 12 kilowatts or more. We’ve seen some that go up to 30 kilowatts when shared by multiple operators.”

That represents a more than tenfold increase in energy use within a decade, a surge which is driven by data-hungry handsets and streaming apps. “People don’t realise how much power is in those small telecom towers,” Smith said. “It’s not a lot per site, but multiply that by hundreds of thousands, and it’s massive.”

Africa, for example, is in the midst of a tower boom. “The number of 2G sites is disappearing fast,” Smith noted. “You can’t even buy 3G equipment anymore; everything is 4G or 5G. In Sub-Saharan Africa, the growth of 5G is faster than anyone expected.”

And that shift has a human story behind it. “I lived in Nigeria for a long time,” he said. “[In Nigeria] we don’t make phone calls anymore, we’re all on FaceTime or WhatsApp. Even in Africa, data usage is skyrocketing.”

The diesel dilemma

For decades, the solution to powering off-grid sites has been simple: diesel. “We’ve sold tens of thousands of small generator sets over the last 20 years,” Smith said. But this model is showing its strain.

Delivering fuel to remote locations, sometimes twice a week, is both costly and logistically complex. “In some countries, like Burkina Faso, the telecom operator becomes the biggest diesel user in the country,” he explained. “If there’s a diesel shortage, the signal goes off.”

This reliance on diesel also clashes with operators’ sustainability targets. “Most of them have signed up to net-zero commitments,” Smith said. “Running thousands of diesel gensets 24/7 obviously doesn’t fit that picture.”

Hybrid power: A practical path to reducing emissions

Caterpillar’s answer is the Cat ETS 150 hybrid power system, a modular, field-upgradable package combining solar, battery storage, and diesel generation for 24/7 reliability.

“Going fully solar is a challenge,” Smith said. “The sun only shines half the day, batteries are expensive, and tower sites have limited space. A hybrid system lets you make the most of solar while diesel ensures uptime.”

Availability is non-negotiable in telecoms. “Operators have to guarantee 99.7% or higher uptime globally, even in the desert or the African bush,” he said. “Hybrid systems make that possible.”

The ETS 150’s design embodies flexibility. “We’ve seen too many systems that cram everything into one box,” Smith said. “When the load doubles, as it often does, you have to throw everything away and start again. Our approach is to make it upgradeable instead.”

Proof in the field

That philosophy was put to the test in Mali, where Caterpillar and Orange deployed an ETS 150 unit in 2023. “We replaced a competitor’s failed hybrid system that couldn’t handle the new load,” Smith said.

Originally sized for 2–2.5kW loads, the site’s demand doubled to 5.5kW within ten weeks due to the shutdown of a nearby tower. “We didn’t need to start over. We added an extra battery, swapped in a larger generator, and upgraded rectifiers, all plug-and-play,” Smith said.

The results were striking as diesel runtime dropped from 24 hours to 10 hours per day. There was a 60% reduction in fuel use and CO₂ emissions, and a 65% cut in maintenance visits. “The payback was just two and a half years,” Smith said. “After that, it’s pure savings.”

Caterpillar’s system anticipates a rapidly changing telecoms landscape. “We size our batteries to last around 10 to 15 years,” Smith said. “We don’t know what phones will look like in 10 years, but we know they’ll use more power.”

He points to the rise of AI as a hidden driver. “If you’ve used tools like ChatGPT, you’ll notice your phone gets warm; that’s because every processor and radio chip is working flat out,” he said. “Even at the handset level, AI is increasing energy demand.”

Connectivity as a catalyst for development

For Smith, the benefits of reliable mobile power go far beyond engineering. “When a community gets connected, the economic growth is phenomenal,” he said. “Mobile banking, education, and healthcare all depend on it.”

He recalled a recent microgrid project in Tanzania: “A nurse told us she once had to perform a caesarean section by the light of a mobile phone. Now, with power and the internet, she can video call a doctor in the city. That’s life-changing.”

As telecom operators race to connect the “last billion” users, Caterpillar sees hybrid power as the key to expanding the use of renewable energy.

“There’s going to be huge growth in remote tower sites,” Smith said. “We need solutions that balance renewables, cost, and reliability and that can evolve as networks evolve.”

His closing thought summed up Caterpillar’s philosophy: “The energy requirements of telecoms are only going in one direction, up. With the ETS 150, we’re ready for that future.”

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