Data centre detox

Data centres use a lot of electricity: so much, in fact, that they are defined by their use of electricity in megawatts (MW) of power load.

The International Energy Authority estimates the sector is responsible for around 1% of total electricity consumed worldwide, with the figure fairly flat over the past five years. While data centres built in recent times are more efficient, their huge power demands, much of which is used to cool the servers, can put considerable strain on the grid.

Until early this year, Singapore had a moratorium on new data centres, whose power use had grown to 7% of the city state’s total, and even now will only approve three new centres over the next 12-18 months. Amsterdam and Dublin have also introduced moratoriums similar to Singapore’s. 

The growth of the digital economy, cloud computing and 5G networks will drive the creation of vast quantities of data over the next decade and all of this needs to be served by data centres. However, real estate investors and managers who develop and own data centres and their ‘hyperscaler’ clients, such as Microsoft and Amazon, are all committed to reducing emissions.

The first challenge is to make the centres as efficient as possible. Data centre efficiency is measured by power usage effectiveness (PUE), the ratio of total energy use to the energy used by the servers themselves. Typical modern data centres operate at a PUE of around 1.3, with some under 1.2. Older centres are far less efficient, however.

Craig Duffy, managing director of fund management at GLP, which is investing in data centres in Europe and Asia Pacific, says: “Sustainable design and operating practice are mission critical for modern data centres. Because data centre operators can spend up to half of their energy cost on cooling, it’s critically important to ensure the cooling equipment is operating at peak efficiency.

“There are techniques that can be used to optimise the air flow within the facility, such as strategic placement of cooling units and leveraging natural convection to minimise cooling power consumption.”

Thomas Liu, real estate partner at private equity firm Actis, which is investing in data centres in Africa, China and South Korea, says the move towards hyperscale centres, rather than multi-tenanted colocation centres, also reduces energy use, as “different tenants in the latter make it more difficult to optimise overall power consumption”.

Nonetheless, the sector still consumes a lot of electricity and, in most of the world, this does not come from renewables. The key to data centre owners meeting their own net-zero commitments, and those of their clients, is sourcing renewable energy. In some cases, this can be bought from power suppliers: however, in markets such as China, all energy must come from the grid, which is largely coal-powered.

Developing data centres close to renewable energy sources has worked in areas such as Canada, parts of the US and the Nordics, where hydropower can be used. A report from data centre operator Digital Realty says firms such as Apple, Google and Microsoft are buying renewables direct from power plant developers and committing to 10-20-year power purchase agreements.

However, Liu says: “It is not straightforward to build data centres in remote areas of developing nations, even if they offer cheap land and access to renewables. Data centres need engineers and it is much harder to recruit outside of major cities.”

On-site power generation is a partial solution, although the huge amount of energy required means that covering a data centre roof in solar panels would scarcely make a dent in the overall energy bill. 

One point very much in favour of the data centre business, but hard to quantify, is that it supports lower-emission businesses: the emissions created by video calls are tiny compared with those from business air travel. 

Furthermore, says Liu: “Data centres themselves represent an improvement on the prior situation, where you’d have servers distributed around a number of corporate headquarters buildings, which was hugely inefficient from an energy use point of view.”

You can read the full version of this story in the May issue of Sustain