The IET: Time To Ditch The Doubts About Demand Side Response For Data Centres?

In a special online supplement for The IET, we outline the environmental and economic reasons why data centre operators should embrace demand side response and battery storage.

“Guide to Data Centre Power Systems” is a special e-publication from by The Institution of Engineering and Technology (IET).

It reflects on the challenges facing the UK data centre industry and the opportunities they present in areas such as power, infrastructure technology, cooling, and sustainability.

Another key focus is demand side response for data centres. We argue that the August power cut impacting a million people across England and Wales should act as a catalyst for action.

Battery storage contributed nearly half (475 MW) of the 1 GW reserve power available to National Grid to bring frequency back into the safe range.

As the country heads into a more distributed, renewables-led energy network, there’s a case that such an example won’t be the exception, it’ll become the norm. Does this mean data centre operators should ditch their ongoing concerns about participating in demand side response?

Debunking The Myth That “DSR Is An Unnecessary Risk”

In theory, data centres should be perfect candidates for demand side response, with their battery-based UPS systems and standby generators.

However, with uptime the overriding concern, too few operators have been willing to get involved.

Using emergency backup for any other purpose is too much of a gamble. The thought seems to be “why compromise system resilience as well as giving up partial control to third-parties, for all too little in return?”.

Does this point of view still stand? For some, there’ll never be any convincing otherwise. But UPS and battery technologies are constantly advancing.

Even though they’re essential parts of any data centre armoury, for much of the time uninterruptible power supplies sit quietly in the background. That makes them an expensive, underutilised asset.

Smart grid ready UPS systems turn themselves into “virtual power plants” capable of storing and feeding power back into the network… without actually compromising on system resilience.

Riello UPS And RWE Rethinking The Role Of A UPS

As evidence, we share the example of our ongoing work with energy company RWE, through its RWE Supply & Trading division.

We’re piloting a smart grid-ready solution using a custom-designed UPS capable of DSR thanks to a special rectifier that enables bi-directional flows of electricity to and from the grid. This UPS is complemented by premium batteries and RWE’s sophisticated monitoring and communications software.

Think back to that major stumbling block preventing data centres from participating in DSR. That it undermines system resilience.

But lead-acid batteries traditionally used in a UPS are extremely difficult to monitor without expensive battery management systems. You can’t be sure of the exact condition of each cell, so can you be certain that they’ll work when you need them too? That doesn’t sound hugely reliable.

On the flip side, sophisticated 24-7 battery monitoring is a must with premium lead-acid or lithium-ion batteries.

This constant monitoring encourages preventive maintenance so that any cells showing signs of weakening can be quickly replaced – enhancing rather than diminishing system reliability.

Powering Into The Future

According to National Grid figures, around 500 MW of battery storage has come online in the last year. It’s predicted UK battery storage could top 8 GW by the end of 2021, enough electricity to power six million homes.

Data centres are some of the country’s biggest energy users. DSR gives them a means of acknowledging this responsibility and helping to secure society’s energy supplies in the years and decades to come.