Reducing the carbon footprint of data centre standby power

Author: Beatrice

The IEA estimates that the energy consumption of data centres comprises around 1% of final electricity demand globally. This figure is understood to rise as high as 4% in the UK and in Ireland to reach 15%. There is clear consensus and impetus within the industry to move to carbon free technology. For example, Google has stated its objective to operate on 24/7 100% carbon-free energy by 2030.

Focus is given, understandably, to how energy demands for key applications such as cooling can be reduced, increasing supply from renewable sources such as solar or wind power. But if data centre operators are to truly run on 100% carbon-free energy, then all methods of energy consumption must be considered.

This should include how standby power is generated, with a clear roadmap established to ensure a transition to low and carbon-free energy without compromising the critical role this plays in keeping assets running during energy outages or times of unpredictable supply. At Finning, exclusive distributor of Cat engines and generators in the UK and Ireland, the company has been working closely with a number of major industry players to establish the best solution to achieve this.

Balancing reliability with sustainability

Current reliance on diesel generators for standby power is well established, primarily because of their practical benefits. They are readily available, reliable as a mature technology and able to quickly ramp up to seamlessly cover issues with main power supplies.

Given that data centres must mitigate any risks that may be posed to maintaining mission critical services for the likes of hospitals and other public services, the advantages in terms of reliability that existing technology offers must be carefully considered as we transition away from fossil fuels.

Indeed, in the understandably risk-averse data centre sector we are likely to see a phased transition to a balance between maintaining the benefits of existing technology with the importance of using carbon-free energy.

HVO proving a smart first step

A first step in this transition is the growing use of Hydrotreated Vegetable Oil (HVO). Produced from certified waste fats and oils, HVO is manufactured using a synthesised process with hydrogen to offer a more sustainable alternative to fossil fuels. Although not entirely carbon-free, HVO can eliminate up to 90% of the carbon emissions compared with the production and use of conventional diesel.

Another key advantage is that it can be used as a drop-in replacement for diesel in many engines, as well as used with existing diesel or biodiesel stocks. For example, provided the fuel meets standard requirements, Caterpillar generators built after the year 2000 are able to run on HVO.

Given the ease with which they can be integrated into existing assets, the company has seen a growing interest from data centre operators in the use of HVO in tandem diesel to lower the carbon footprint of their standby generators.

Whilst use of HVO with conventional diesel has been the most common approach, there have been high profile cases where a move to 100% HVO has been taken – allowing even greater reductions in carbon emission. Last year Microsoft announced that all Cat generator sets at its new data centres being constructed in Sweden would run on HVO, providing the final element to obtaining all of its energy needs from renewable sources.

“We have worked extensively to ensure that our new data centres in Sweden will be among our most sustainably designed and operated in the world,” observes Noelle Walsh, Corporate Vice President, Cloud Operations and Innovation at Microsoft. “Caterpillar and the Cat dealer network have developed innovative power solutions that support Microsoft and our unwavering commitment to carbon reductions. Cat generator sets at Microsoft data centres help us keep availability promises to our customers even when grid power fails, providing continuous energy and uninterrupted cloud services.”

In short, with largely immaterial differences in performance and consumption in comparison with diesel, HVO provides an excellent next step to reducing carbon emissions. Crucially, it offers flexibility with any HVO:diesel ratio between 0% and 100% possible depending on the specific demands and preferences of each project.

Longer term benefits of hydrogen

Whilst HVO is a convenient and highly effective drop-in replacement for existing diesel equipment, it is not entirely carbon-free. Furthermore, the sheer scale of demand for fuel means that it is unlikely to become a permanent solution due to its production being limited by how much vegetable oil and fat is available globally. 

Hydrogen has been touted as a more likely long-term solution, with advances in blue (the splitting of natural gas into hydrogen and CO2, with the resulting carbon captured) and green (splitting water by electrolysis into hydrogen and oxygen) production set to help create the volumes needed to replace fossil fuels on a global scale.

Whilst those production volumes are yet to come, plans are in action, and it is an area that data centre operators should explore when looking at the next generation of sustainable equipment. As with HVO, a blended approach may be the likeliest next step with gas gensets configured to allow for a blended fuel containing up to 25% hydrogen.

Manufacturers such as Caterpillar are rolling out gas generators configured out-of-the-factory to enable operation on natural gas blended with hydrogen. Adaptation of existing gensets can be done with the use of retrofit kits for some equipment, making it an appealing quick win as hydrogen availability increases.

Rising industry interest and development of hydrogen supply infrastructure means that 100% hydrogen gensets are in advanced stages of development and we will likely see trials of this equipment in the near future.

Where next for data centres?

For those that haven’t already adopted it, HVO is the next natural step to take as trials on 100% hydrogen gensets move forwards. Adding Selective Catalytic Reduction (SCR) can also make a notable difference in minimising NOx emissions.

The company is also seeing a growing number of new sites considering the use of a microgrid system which allows a combination of power generation sources (photovoltaic solar modules, energy storage, gas and diesel). Smart microgrids mean efficient power that can be produced where and when it’s needed without transmission lines and transformer losses. These high performance, scalable systems are designed and built using standardised building blocks that are easy and quick to install even in challenging environments.

With the potential risk if transition of standby power is not delivered smoothly, it’s also critical to ensure you have the right partner to identify the best solution for your specific requirements. Working with a specialist such as Finning means you can not only access this invaluable expertise and advice but also gain insights into the latest testing and performance information as newer technology such as hydrogen gensets are brought to market – helping you to get maximum uptime with minimum carbon emissions.