New Sustainability Metrics for Datacenters from the Green Grid

Summary

In this interview, Nick Dubet, data center efficiency strategist at HP and member of the Green Grid, discusses the evolving landscape of data center sustainability. He highlights key metrics such as Power Usage Effectiveness (PUE), Energy Reuse Effectiveness (ER), Water Usage Effectiveness (WUE), and Carbon Usage Effectiveness (CUE), which are vital for reducing energy consumption and environmental impact. Nick emphasizes the importance of using renewable energy, optimizing cooling methods, and addressing the carbon footprint of electricity sources. The conversation encourages companies to adopt these metrics and engage in sustainable practices for long-term efficiency and environmental responsibility.

Takeaways

• 😀 PUE (Power Usage Effectiveness) is a key metric that has driven energy efficiency improvements in data centers, but further gains are now incremental.
• 🌍 Sustainability in data centers extends beyond just energy efficiency to include the overall environmental impact, such as water and carbon footprints.
• 🔋 Achieving a PUE of 1.07 is considered optimal, but the focus is now shifting to other sustainability metrics due to diminishing returns from energy efficiency alone.
• 💧 Water Usage Effectiveness (WUE) is an important metric to track how efficiently data centers use water for cooling, particularly in regions where water conservation is critical.
• 🔥 Energy Reuse Effectiveness (ER) focuses on repurposing the waste heat from data centers to support district heating or other industrial uses, reducing their net energy footprint.
• 🌱 Carbon Usage Effectiveness (CUE) tracks the carbon impact of electricity used by data centers, with renewable energy sources like wind and hydro having significantly lower carbon emissions than coal-powered energy.
• 🔄 Liquid cooling is becoming a more viable solution in data centers, with potential to replace traditional air-based cooling systems, offering more efficient heat transfer.
• 💡 The industry's future goals include greater adoption of energy reuse practices, such as using data center waste heat for useful purposes like district heating.
• 💸 In many regions, coal-powered electricity is cheaper than renewable energy, making it financially attractive despite the higher carbon footprint, but this may change with future carbon taxes.
• 📈 The Green Grid is pushing for broader awareness of sustainability metrics like ER, WUE, and CUE, and hopes to establish a 'Green 500' list for top-performing sustainable data centers.

Q & A

What is Power Usage Effectiveness (PUE), and why is it important in data center sustainability?

PUE is a metric used to measure the energy efficiency of a data center by comparing the total amount of power consumed by the data center to the power used by the IT equipment itself. It’s important because it helps data centers identify energy inefficiencies and focus on improving their energy usage. A lower PUE indicates a more efficient data center.

How has PUE helped improve energy efficiency in data centers?

PUE has driven significant energy efficiency improvements over the past decade. The best-performing data centers now achieve PUEs around 1.07, which means they are spending only 7% more energy on cooling and power infrastructure than the actual computing workload. This represents a huge leap in operational efficiency from the past.

Why is it difficult to reach a PUE of 1.0, and what does this mean for data center optimization?

Achieving a PUE of 1.0 is nearly impossible because there will always be some overhead in the system, such as cooling and power supplies. Even with advancements like free air cooling, there are diminishing returns as PUE approaches 1.07, meaning further energy improvements are becoming harder to achieve with this single metric.

What other metrics are important to consider in data center sustainability beyond PUE?

Beyond PUE, new metrics have been introduced to track broader aspects of data center sustainability: Energy Reuse Effectiveness (ER), Water Usage Effectiveness (WUE), and Carbon Usage Effectiveness (CUE). These metrics focus on how data centers reuse energy, how much water they consume for cooling, and the carbon footprint of their electricity sources.

What is Energy Reuse Effectiveness (ER), and why is it significant?

Energy Reuse Effectiveness (ER) measures how effectively a data center can repurpose the heat it generates for useful purposes, such as district heating or industrial processes. It’s significant because it helps reduce the environmental impact of a data center by turning waste heat into something beneficial, offsetting the data center's energy footprint.

How does water usage impact the sustainability of data centers?

Water usage is a critical factor because many data centers rely on evaporative cooling systems, which consume large amounts of water. In dry, sunny climates, this can lead to significant water evaporation, raising concerns about the environmental impact of water usage and how it balances against energy consumption efficiency.

What is Carbon Usage Effectiveness (CUE), and how does it affect data center sustainability?

CUE measures the carbon footprint of the electricity used by a data center. It considers the source of electricity, such as coal, hydro, or wind power. The goal is to reduce the carbon footprint by choosing renewable energy sources. The metric emphasizes the environmental impact of the energy supply itself, which is crucial for reducing overall carbon emissions.

Why is the location of a data center important for sustainability?

The location of a data center is critical because it influences both cooling efficiency and the carbon footprint of the electricity used. For example, locating a data center in a cold climate can take advantage of natural cooling, while placing it in a region that uses renewable energy sources reduces the carbon footprint. Locations with high reliance on coal-fired electricity can increase emissions, making energy costs cheaper but less sustainable.

What role does liquid cooling play in enhancing data center sustainability?

Liquid cooling is more efficient than air cooling because liquids are better at transferring heat. It allows data centers to operate at higher temperatures, reducing the need for water and energy-intensive cooling methods. This technology is being explored to help data centers use less power and water while maintaining efficient cooling.

What is the business case for adopting sustainable practices in data centers, even if carbon taxes aren’t yet widespread?

While carbon taxes aren’t yet widespread, companies should still adopt sustainable practices because future regulations could impose costs on carbon emissions. Additionally, extreme weather events and shifting climate conditions could lead to stricter policies in the next few years. Sustainable practices can help data centers mitigate risks and reduce long-term operational costs, even if the immediate financial incentive isn’t clear.