Clearly, increased capacity must be designed and built with stable power supply and NetZero targets in mind. Managing energy efficiency is core to achieving this. Since you cannot manage that which you do not measure, the power usage effectiveness (PUE) metric has become a de facto industry standard for measuring how efficiently a data centre uses energy. To improve efficiency, datacentres need to deploy Heating, Ventilation, and Air Conditioning (HVAC) technology that will deliver a low annual average PUE.
A few years ago, the annual average HVAC PUE’s were around 1.9. Current PUE figures hover around 1.5 and there is constant effort going into lowering this to 1.0. Incorporating free cooling, free heating and specifications on the efficiency of operating equipment in the HVAC designs lowers the annual energy utilisation and drives down the annual average PUE.
Another strategy to increase a data centre’s energy efficiency is widening its internal temperature and humidity range and performing upfront planning to ensure ease of maintenance. It is also important to consider improving the power usage of IT equipment by lowering the payload power that it requires. Servers consume 60% of this, so that further efficiencies can be realised by cleaning up server workloads and eliminating unnecessary usage, virtualising more workloads and replacing older and less efficient servers with new ones.
Finally, data centre owners need to optimise physical datacentre space, particularly for datacentres that were built before server virtualisation became commonplace. Less space needed equates to less cooling and thus power savings.
Energy efficiency improvements alone will not stabilise power supplies, though. In the urban context, renewable energy from rooftop solar PV panels can be incorporated into a build to offset some of the data centre’s reliance on the local grid. However, the power contribution from a rooftop solar microgrid would not be sufficient to meet the demand of a power-hungry datacentre. For this reason, we are seeing more interest in alternative energy solutions that comprise of a tri-generation plant using natural gas to power the datacentre and off grid, with diesel generator backup for downtime periods. Important to this is securing a site in a hotspot area with access to gas lines to secure a consistent supply.
Though tri-generation and improved energy efficiency are all steps in the right direction, further thought must be given to renewable energy if NetZero is the goal. Fortunately, Africa’s potential for producing renewable energy is vast. The challenge is space, which is not readily available in urban centres.
To reach NetZero, data centre owners could look to trends out of other markets where investing in renewable energy plants and microgrids - like a solar or wind power farm for a large data centre – are showing promise. In Africa, this approach opens new opportunities to establish data centres in more remote parts of the continent that previously have not been considered due to a lack of infrastructure, but where space is more readily available. This approach feeds the datacentre directly from its own self-sustainable supply of renewable energy, while also boasting cleaner energy use and improved carbon reduction.
In this context, the business case for solar is particularly strong. South Africa, for example, receives more than 2 500 hours of sunshine per year, with average solar-radiation levels ranging between 4.5 and 6.5kWh/m2 in a single day. The country’s average solar radiation of about 220 Watt per square metre is more than double that of Europe (100 W/m2). Solar, therefore, is one of the most promising renewable energy options to reduce dependency on the grid. The Northern Cape has become a hotspot for solar power plant investments given the impressive solar power generation potential in the area – and we have seen successful examples of solar powered data centres being established in similar arid and desert type environments in other parts of the world.
While there is currently no set of industry standards for building “green” data centres, with the global shift towards NetZero driving the need for carbon reduction, we expect such standards will become a reality in the datacentre industry in future. We have seen the trend play out in other commercial property spaces, where green building has become a requirement for most major developers.
This shift will place more emphasis on the role of architects and consulting engineers to continue to produce alternative and operationally cost-efficient designs that reduce energy consumption, reduce carbon emissions and improve the overall operational efficiencies of new datacentre projects.
As an organisation that is globally committed to achieving NetZero, WSP fully embraces the opportunity that the digital era holds. We are committed to working with our clients rethink how data centres are designed, built and operated with sustainability principles at their core. This approach ensures that data centres not only perform well in today’s context, are but future-proof by design.
