Co-authors: Joshua Randall and Zach Lasiuk
Earlier this year, the United Nations Framework Convention on Climate Change (UNFCCC) reported that current climate commitments will not sufficiently limit global warming. To restrict global temperature increases to 1.5C, we all need to do more. Arm has committed to achieve carbon net-zero by 2030 by 2030 and is working to decarbonize compute, leveraging low-power, high-performance foundational technology to drive down energy consumption and help reduce emissions.
In pursuit of this, my team and I investigated how we can operationalize the decarbonization of compute beyond the surface level for ourselves and our partners. Our research formed part of our participation in the UN Global Compact’s Young SDG Innovators Program (YSIP). The 10-month program sees teams of young professionals develop solutions that deliver market value for their company but also drive progress on the Sustainable Development Goals.
The result was a tool called the Carbon Advisor (CA), which allows users to make informed decisions about the carbon impact of their compute workloads. By considering carbon alongside cost, performance and quality it helps users choose between cloud providers, instance types, and compute locations.
So why did we focus on datacenters?
In 2010, datacenters consumed around 1% of global electricity use. But the share of total compute electricity use is shifting towards the cloud and hyperscale, efficiency improvements are becoming harder and harder to attain, and demand is increasing. We need a data-oriented approach to achieve a clear view of the carbon cost of our activities, so we can use that information to lower carbon emissions.
When assessing how best to design, maintain, and utilize datacenter compute – and minimize the greenhouse gas (GHG) emissions of a datacenter – there are some factors to consider:
This is not a complete list, and yet it demonstrates the wide variety of influences that affect the final carbon cost of a datacenter. Some effects are determined at the earliest stages in a datacenter’s development, like the manufacturing of silicon contributing to embodied carbon emissions. Others only come into play during active operation, such as grid carbon intensity. There is also a variety of data availability represented: grid carbon intensity statistics are typically easier to procure than embodied emissions, for instance, and only recently have approaches been attempted that measure holistically across this larger life cycle.
An operationalizing solution must start somewhere. Consideration data availability and the influence that Arm is most capable of (a topic covered later on), our team focused primarily on applying measurements of grid carbon intensity and server hardware power efficiency.
The tool shows data views from both the datacenter user (carbon emissions per product) and provider (performance output per product) perspectives and supports comparison of up to three solutions. By selecting parameters such as the target workload, compute source and type, and location, users can gain a breakdown of the carbon emissions associated with each solution. Using this information, users can make more carbon-conscious decisions about their resource management with a finer granularity and full awareness of their final carbon impact. Rarely is carbon cost considered a primary design decision; the Carbon Advisor is a step towards enabling that practical consideration.
An anonymized screenshot of the prototype Arm Carbon Advisor
Our first task was to identify the differing requirements of each user group.
A user wants to accomplish a set level of work emitting as little carbon as possible. They can achieve this by choosing their cloud provider, type and size of instance, and where their resources are housed as mindfully as possible to limit their emissions. Shown below are the factors they control directly or indirectly in this process.
The provider aims to maximize the total performance/utility for a given workload within the bounds of a fixed power (and carbon) amount.
Achieving this level of transparency and granularity in applying the carbon lens to the datacenter is feasible, but procuring reliable and transparent data is a challenge. The following examples show the complexity of the issue:
Current standards of data availability, accuracy, and transparency limits access to concrete data on carbon metrics. Without that concrete data, making informed carbon-conscious decisions is a difficult task. The CA makes the caveats and assumptions made in its calculations clear, but an ideal solution would utilize data that is fully vetted and transparent. This is something that can only be possible through open communication between vendors and users. To achieve the larger sustainability goals of the ICT industry – and the world – a concerted and collaborative approach across our industry is needed.
Learn more about Sustainability at Arm
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