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Making meaningful gains towards greener data centres

October 13, 2022

Singapore’s three-year moratorium on new data centres recently ended and there is now an opportunity for the city-state to lead the way in reimagining what a green data centre could look like.

Green data center blog post graphic

Data centres have had a bad reputation in recent times as energy guzzlers – but that doesn’t tell the whole story. In 2009, one petaflop of compute required 24MW and 2000sqm of space. In 2020 the equivalent could be performed with 200kW and eight racks. In the last 15 years, server efficiency has improved 17-fold. Concurrently, in Singapore, infrastructure supporting IT has improved from an average PUE 2.1 to the current PUE 1.25. In fact, the hyperscalers or single user data centres have reported PUEs of 1.13 to 1.17 in Singapore.

Data centres are a vital component of the global economy and the backbone of the highly digitalised world we live in. The internet, and the cloud which stores all our data, emails, photos and videos rely on data centres to exist, requiring a huge amount of energy to support all the data traffic. However, rapid growth in data traffic need not necessarily result in an increase in energy utilisation, thanks to efforts to introduce greater energy efficiency within the industry.

In fact, efficiencies introduced into servers, power supplies, cooling and networking have managed to offset higher processing rates, storage and traffic. Between 2010 and 2018, data centre capacity increased by 600%, internet traffic grew by orders of magnitude, and storage capacity increased by 25 times. But data centre energy use only grew by 6% over the same period, pointing to the value of ensuring that more data centres embarked on a sustainable path.


Pushing the boundaries for greener DCs

But with the amount of data the world generates and consumes, growing rapidly each year, data centre providers need to continually make efforts to minimise our carbon footprint.

Concerns about the environmental impact of data centres have prompted authorities to put more focus on the construction of greener data centres. Singapore, having lifted its moratorium recently, has introduced stringent standards on data centre efficiency. Likewise, hyperscalers are also constantly looking to minimise their carbon footprint, with Google setting a goal to use clean energy to fully power their data centres by 2030. Microsoft is also looking at becoming a carbon negative, water positive, zero waste company by 2030.

The industry is striving to push boundaries in terms of energy and water usage, as well as IT loads.

But the challenge in making data centres green varies depending on regions and access to resources. In Asia for instance, it is easier to keep data centres cool in the temperate climates of Korea and Japan than it is in tropical Singapore. Approximately 37% of the total energy consumed by data centres in the city-state is used to cool IT equipment. Cooling architecture/topology then plays a role in determining how to get the significant improvements in energy efficiency.  Heat rejection, water or air, is feasible in Singapore, but it would be less ideal in a number of Asian countries including Indonesia and India where water stress will be a medium to long term issue.

Singapore is a great place to start when analysing how data centres can innovate on the path towards sustainability. I’ve always been a proponent of water over air, but this could be the time to look at alternative means. It could mean the use of air economisers or direct air to cool data centres.

In 2018 I did a presentation on Cooling Architecture for Low PUE in Tropical Climates (refer to the figures below for air quality in Singapore then). The quality of air in Singapore was such that direct air cooling could be used. Could this be a time to relook at such an architecture again?

There are several factors to consider when looking at air cooling, such as ability to control the temperature, humidity, dust, as well as gaseous contaminants such as sulphur bearing gases to reduce copper creep or corrosion of silver metallisation in miniature surface mounted components. If you refer to the charts below, the air quality in Singapore falls within range of acceptable standards.  Eg. (ANSI G1 Gaseous Airborne Contaminants)

Air quality data chart

 Data Source: National Environment Agency (NEA), Singapore / Department of Statistics, Singapore

Despite its challenging climate, Singapore is a good example where boundaries can be pushed in to ensure more efficient use of energy in data centres. Authorities in Singapore have mandated that new data centres built must fulfil a PUE of 1.3 or less.


Sustainability roadmap

While much of the effort to enhance efficiency has centred around facility systems and improving the efficiency of powering and cooling data centres, there is plenty of scope to improve the efficiency of IT devices and software as well.

There is a complex interplay at work between IT systems and facility systems that determine the energy performance of data centres and having a silo approach between the two often results in over-provisioning.

In terms of IT components, servers play a key role in determining the energy efficiency of data centres. Currently the most significant issue affecting server energy performance is the power used at zero processor utilisation. While there are techniques to invoke a sleep state for processors that saves energy, the latency involved when waking from a sleep mode at a time of high demand is a challenge that needs to be overcome.

Further, as we continue to innovate, facilities, IT components, and software will steadily improve in energy efficiency and performance.

As we have seen, trying to improve energy efficiency of legacy data centres can be challenging due to the way these facilities were originally designed. The big challenge then is to future-proof current designs to allow flexibility to integrate new technologies that would continually upgrade the efficiency of the data centres.

For the sake of our society and planet, it is a challenge that all of us need to live up to.