Cutting the Carbon Footprint of Servers

Cloudflare’s approach to sustainability is rooted in a simple principle: the hardware that powers its global network should be efficient, reusable, and recyclable. As the internet continues its exponential growth, even small efficiency gains in today's infrastructure will yield significant environmental benefits in the future. The company's focus is on reducing the total carbon footprint of its servers, which can reach approximately 6 tons of CO2 equivalent (CO2eq) per unit in the US.

A computing device's full carbon impact can be broken down into four phases:

  1. Embodied emissions, which come from source materials and production.
  2. Packing and shipping.
  3. The energy used during operation.
  4. End-of-life disposal.

Of these, operational energy use is by far the largest contributor. While the energy required to complete a given workload is fixed, the key is to improve the amount of computing output per unit of CO2 emitted. This is achieved through continuous hardware upgrades to the most power-efficient designs, which also aligns with Cloudflare’s cost incentives. Embodied emissions—those from manufacturing—account for roughly 10% of the total lifecycle impact, but this is an area where infrastructure operators have more control through design choices, standards, and recycling.

Extending Hardware Life with Modular Design

One of the most effective strategies for reducing embodied carbon is modular system design. Instead of replacing an entire motherboard for each new CPU generation, modular design decomposes the board’s functions onto separate sub-boards. This allows operators to upgrade only the components that deliver the greatest performance or efficiency gains—often CPU and memory—while keeping the rest of the system in place.

For instance, if 30% of a server needs upgrading to meet efficiency goals, it doesn't make sense to scrap the entire unit. Traditional “glue logic” components, like standardized I/O interfaces, rarely get faster and can serve for years. Modular design prevents the creation of 70% in unnecessary embodied carbon by amortizing these long-lived components over a longer period. This approach not only cuts emissions but also improves reliability and supply-chain resilience, as sub-boards are better tested and can be sourced from a wider range of vendors.

Open Standards Unlock a Circular Economy

Even with modularity, dated servers inevitably face retirement. Historically, many ended up in landfills. The problem was that proprietary firmware, BIOS, and interconnects made these systems costly or impossible for other buyers to repurpose. High service fees for closed-source support often made second-hand servers uneconomical to reuse.

The solution lies in standardization. When servers can be operated using open-source firmware and BIOS, the cost of refurbishment falls dramatically. This enables other service providers to integrate used parts into their own systems, creating a true circular economy where hardware gets a second life rather than prematurely reaching a wasteland.

Responsible Recycling of E-Waste

Eventually, some parts will fail or become too inefficient even for the secondary market. At this stage, metal recycling remains a viable option, though the energy cost of extraction sometimes outweighs the benefits. There is promising innovation in the field, such as research by Zhan et al. (2020) demonstrating a hydrothermal-buffering technique for recycling GaAs-based integrated circuits, achieving gallium and arsenic recovery rates of 99.9% and 95.5%, respectively.

Adoption of such advanced metal recovery techniques is still limited, with many manufacturers focusing more on water and renewable energy initiatives. Cloudflare is closely tracking these developments to capitalize on any future breakthroughs that make electronics recycling more sustainable and practical.

Modularity Over Full Redesigns

Each server generation at Cloudflare has historically demanded a from-scratch redesign: a new CPU meant a new motherboard, power supply, chassis, memory DIMMs, and baseboard management controller (BMC), often dragging fans, storage, network cards, and cabling along with it. But many of those components aren't changing dramatically generation to generation — they're built on older manufacturing processes and use interconnection protocols that don't require cutting-edge speeds.

Consider the current Gen 11 server. A single-socket system runs at roughly 450W, with the CPU and its associated memory consuming about 320W of that (up to 360W at peak load). Everything else — storage, fans, BMCs, programmable logic devices — accounts for roughly 100W of operational power, dominated mostly by fans. That's not where the efficiency gains from newer ICs will show up. So rather than rebuilding those parts fresh each cycle and racking up more embodied carbon, Cloudflare is reusing them wherever possible.

Disaggregating the components that change for efficiency reasons from the rest of the system-level functions maximizes reuse across generations. The analogy is upgrading a car's engine for better fuel economy without scrapping the frame, seats, and windows that still work fine.

Open Standards as a Circular Economy Enabler

True modularity across the industry requires interoperability across interfaces, standards, and vendors — if the goal is a 70% reduction in e-waste, no single company can get there alone. Cloudflare's Gen 12 servers are being built around standard add-in-card form factors (OCP 2.0 and 3.0 NICs, Datacenter Secure Control Module for security and management), and the next design leverages the open-source Datacenter Modular Hardware System specification, which lets modular subcomponents connect across common buses regardless of system manufacturer. That allows components to be maintained over multiple generations without incurring new carbon debt on parts that don't change as often as CPUs and memory.

OpenBMC is now a requirement for all Cloudflare vendors, with fixes upstreamed to the community. Open system firmware delivers security through auditability, but its sustainability value is that a new party can take over support for a server that might otherwise be destroyed. Apart from data-bearing assets, which are destroyed per security policy, 99% of Cloudflare's hardware is repurposed — cutting the number of new servers that must be built to meet global capacity demand.

Efficiency Tuned for Real Workloads

The other lever is deploying power-efficient architectures tuned for actual traffic patterns. Gen 11 servers in production handle about 25% more requests than Gen 10 for the same energy — roughly what testing predicted in mid-2021, and notable given that new products and services launched since then couldn't have been part of those original benchmarks.

The traditional efficiency metric — requests per second per watt — was built for comparing multi-generational servers running a fairly narrow product set. But Cloudflare's network now serves as an intelligent threat detection system and a development platform for customers. As with any benchmark, fast performance in one domain (SpecInt_Rate, STREAM, etc.) doesn't guarantee speed in another: AI inference, video processing, and bulk object storage each stress different parts of the system. Validating the next server generation means weighting all these workloads by their actual prevalence, not just request counts.

Domain-specific accelerators are another avenue. Application-level ones, like AV1 hardware acceleration for Cloudflare Stream, look promising. Infrastructure accelerators (Smart NICs) are also under evaluation. But new silicon only helps if it's more efficient than what it replaces — and node-level performance analysis can miss the complexity of fleet-wide deployment across a distributed network. The approach is deliberately measured.

Standardizing Emissions Reporting

Individual company efforts can only go so far. There's a notable gap in standards for emissions reporting across server component manufacturing and operation. Cloudflare is engaging with bodies like the Open Compute Project to help define industry-wide sustainability metrics.

The Greenhouse Gas (GHG) Protocol has made progress on internationally accepted accounting and reporting standards. It defines scope 1 emissions as direct carbon accounting of a reporting company's operations — relatively straightforward to calculate — and scope 3 as indirect value chain emissions. For standardized metrics across the full lifecycle of generating equipment, the industry needs consistent carbon footprint data for subcomponent manufacturing, supply chains, transportation, and data center construction methods. Getting embodied carbon measured uniformly across vendors is a prerequisite for defensible, industry-standard metrics.