AWS has set itself three ambitious sustainability goals: achieving net-zero carbon by 2040, using 100% renewable energy by 2030, and becoming water-positive by 2030.
These are no small feats for a company providing the connectivity that powers global innovation across 245 countries and territories spanning 111 availability zones.
AWS has already hit one of these targets — achieving 100% renewable energy in 2023, seven years ahead of schedule. The milestone was made possible by over 500 renewable energy projects worldwide, ensuring consistent access to clean power.
Leading the charge to meet the company’s other milestones in this area is Chris Walker, AWS’s director of sustainability.
In tandem with its hyperscale competitors, the company is rapidly scaling its infrastructure to meet surging digital demands, with new cloud regions in Thailand, Mexico, and Taiwan exemplifying its global expansion.
Walker emphasised that AWS is committed to scaling responsibly, with efficiency and holistic thinking at the heart of its newest projects and programmes.
In an interview with Capacity, Walker shared insights into AWS’s sustainability and energy-efficiency efforts, from data centres to hardware recycling.
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Energy efficiency at scale
It sounds simple: shifting a business’s energy from traditional sources to renewables. The reality requires investment, a deep understanding of how your business consumes energy and mindset changes.
Walker outlined to Capacity that AWS was able to hit its renewable energy target seven years early by holding itself to account and making concerted, well-thought-out changes.
The results positioned Amazon as the largest purchaser of renewable energy in the world for four years running, with billions invested in solar and wind projects globally.
Change like this doesn’t happen overnight: AWS has undertaken 240 utility-scale and 270 on-site solar projects that are not simply supporting data centres but everything from fulfilment centres to corporate offices.
And the energy evolution goes on, with AWS now facing the mammoth task of achieving net-zero carbon by 2040, as well as returning more water to communities than it consumes by 2030.
Walker says that despite hitting its renewable-energy target in 2023, AWS continued to strike new clean-energy deals.
These include agreements with X-energy, Energy Northwest and Dominion Energy to deploy small modular reactors (SMRs) that provide carbon-free energy and further reduce the company’s reliance on fossil fuels.
Hyperscalers like AWS have increasingly turned to nuclear SMRs, which are capable of generating both power and processing heat, and can be placed directly on-site or near facilities like data centres, providing long-term sources of energy while reducing dependency on the local grid.
Walker says AWS’s nuclear efforts show the company is “doubling down and making sure that we're putting our money where our mouth is”.
He continues: “We're also signalling to the industry and signalling to the broader space that we are serious about this technology. Not only is renewable energy a massive part of our portfolio and our path to net-zero carbon, but nuclear and other carbon-free energy are part of that path for us as well.
“Those three agreements, in addition to all of the work that we’ve done with our renewable energy space, shows that we are serious about it, but we’re also really excited about the path to net-zero carbon by 2040.”
Efficiency by design
It’s not just supply-based factors that have helped AWS improve its energy efficiency but the design of its sites.
At the turn of the year, AWS unveiled a new design for its data centres that rethinks everything from power to cooling and hardware to maximise efficiency.
The hyperscaler overhauled its rack designs, electrical distribution and mechanical systems, and facility cooling to increase efficiency and add flexible support for increasingly dynamic workloads.
Walker describes the overhaul as a “holistic approach” to scaling its infrastructure: “[We] simplified our electrical design and distribution, allowing us to use the electricity that we’re consuming on-site in a much more efficient way.
“We’ve also made a lot of improvements in how we optimise landing our racks within data centres.”
Walker highlights the cooling-system revamp as a change that helped reduce mechanical energy consumption by 46%.
The results of the infrastructure redesign, according to Walker, could have a positive impact on AI workloads: “These capabilities are going to help us not only power generative AI, but also allow us to use energy in a much more efficient way at that rack level.”
Re:Cycle and the feedback loop
One example of AWS’s sustainability efforts is its Re:Cycle Reverse Logistics hubs, which test and repair equipment from its data centres.
In 2024, the company said all of its decommissioned racks sent to such hubs were diverted from landfills, either being recycled or sold into the secondary market.
Walker says the success of the reverse logistics project has stemmed from deploying the right assets, explaining: “We put the right resources around it and the right teams in this space, being intentional. This is one of those areas that we knew we needed to build programmes around.”
He says the focus on a feedback loop in which teams are communicating efficiently elevated the project from a simple reverse logistics effort to something that makes a tangible benefit to areas like resource management of recurring precious metals, but also to secondary market customers purchasing refurbished units.
“We organised ourselves around three main pillars,” Walker explains. “The first is around designing better, partnering with our hardware engineering teams to design the chips, racks and materials going into our data centres with circularity in mind. “The second is around operating longer, both ensuring we have robust maintenance programmes and the right operational mechanisms in place if we do decide to extend the lives of our servers that we have the confidence there won’t be any issues.”
The last pillar behind the success of the Re:Cycle project has been recovering more: “What’s exciting for us is to figure out ways to not only fold materials back into our supply chain, but also reuse or recycle them on the secondary market,” says Walker.
“Since 2023, over 23.5 million components have been recycled or resold on the secondary market, so we're not just diverting them from landfill, but also looking at what we can do with those.”
Other net positives that AWS has reported from the project include sourcing 13% of spare parts from its own reuse inventory and working with suppliers to increase the level of recycled or bio-based plastics to at least 30% in plastic server rack components.
Walker outlined that these positives have come from the feedback loop, with the project looking to explore further areas like scaling repair and reuse, and increasing material recovery.
“It gets exciting when you start connecting all three of those pillars, bringing the feedback back into it,” Walker said. “That’s where we're going to start seeing those data points and the step-chain increases really happen.”
This article first appeared in Capacity's February 2025 magazine
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