Uncontrolled grid voltages are growing threat to data centre operations

The need for data centres to access reliable, high-quality electricity is obvious. But around 60% of data centre downtime is attributable to power problems, including growing incidents of dangerously high voltage surges.

Part of the problem is that the UK electricity industry is struggling to adapt its transmission and distribution system, designed in the 1950s, to a new era of hyper-dynamic generation and consumption. And the demands of data centres is adding to the strain.

The key issue is not just increasing generating capacity to meet growing demand. It is how to accommodate thousands of widely dispersed, intermittent sources of renewable energy, together with millions of EVs, heat pumps etc. – and data centres – in a system originally build around centralised power stations and predictable loads.

One of the most serious effects of the transition is the growing inability of network operators to control voltages, as patterns of supply and demand become ever-more volatile. This results in increasing numbers of over-voltage events, with multiple effects for electricity users.

Voltage instability effects

Uncontrolled voltages cause electrical equipment to operate inefficiently, wear out prematurely – and trip out when safe voltage levels are exceeded. Scenarios in which over-voltage has played a cardinal role include the disastrous Spanish/Portuguese outage of April 2025.

And regionally inadequate voltage control systems can prevent data centres connecting to the grid.

New measures to incentivise network operators to implement effective voltage control solutions are expected in Ofgem’s RIIO-ED3 five-year electricity distribution price control framework. But that will only start in 2028.

Meanwhile, the industry’s Voltage Matters Forum, which has more than 400 members, indicates that, while voltage control is recognised as a system-wide issue, voltage problems are growing rapidly – and efforts to fix them are piecemeal.

The electricity industry is running to catch up with an accelerating voltage control problem – and needs to run faster. But what can data centre operators do to help themselves? And why?

Growing problems The International Energy Agency (IEA) reports that large data centres can consume up to 250MW – equivalent to a substantial city. They already account for up to 3% of global electricity use, rising 12% per year. And in hot spots like Ireland, they are projected to use up to 30% of electricity by 2028.

That puts many data centre operators in the league of significant Private Network Operators (PNOs), approaching the scale of utility Distribution Network or Service Operators (DNOs/DSOs).

The good news is that technologies to control voltages efficiently and cost-effectively have already been developed. UK network operators may be slow in adopting them – and need regulatory stimulus to deploy them system-wide – but they are proven to deliver multiple benefits for suppliers and their customers. These include reduced need for network reinforcement, lower energy use and costs, plus more reliable service.

Control technologies

Voltages in the pre-renewables era were controlled by electro-mechanical transformers and tap changers, which worked fine and still do in many cases. But on their own, they are not smart or fast enough to deal with the large and sudden changes in supply and demand that cause voltage instability.

Automatic Voltage Controllers (AVCs) are now available that use smart algorithms to manage fluctuations in load and voltages instantaneously. These can be added to network systems in the form of plug-and-play units, or increasingly in software-only versions.

Developers have recognised that the requirements of data centre electrical systems operators may be less complex than those of utility companies, so they have produced stripped down versions. These have all the core AVC functionality of utility units, so they can be deployed more easily in-house or by third party service providers.

Developers have recognised that the requirements of data centre electrical systems operators may be less complex than those of utility companies, so they have produced options specifically tailored for this application. These have all the core AVC functionality of utility units, so they can be deployed more easily in-house or by third party service providers.

In-house solutions

Many data centre operators already enjoy high quality, reliable, voltage-controlled energy from their suppliers. But given the growing voltage problems across the grid, plus delays in adopting system-wide solutions, there is a strong business case for implementing voltage control technologies independently.

It may also be sensible to include voltage control as part a broader regime for managing electrical assets in-house, to minimise risk and maximise uptime.

Comprehensive asset management solutions have been developed specifically for data centres, based on technologies which are well proven to maximise uptime and reduce costs for utility companies. These include continuous monitoring of equipment to detect problems before they lead to failures, condition-based risk management, whole-system visibility and energy efficiency.

The electricity industry is under increasing pressure to make a 70-year-old transmission and distribution system fit to cope with unprecedented changes in supply and demand – and by its own admission, is not adapting fast enough in some areas.

So while data centre operators critically require 100% reliable electricity, on demand 24/7, they may be wise to adopt measures for ensuring it themselves.