Summary
- Voltage instability is becoming a sharper operational risk as power systems absorb more intermittent generation and fast-changing demand.
- Automatic voltage control can help sites manage over-voltage events, equipment stress, and reliability exposure closer to the facility.
- Data centre operators may need to treat voltage control as part of wider in-house electrical asset management, not only as a utility issue.
Data centres are absolutely dependent on reliable electricity, but we are already seeing up to 60% of their downtime attributable to power issues, including growing incidents of dangerously high voltage surges.
There is a strong case for data centre operators to adopt voltage control technologies in-house, as the UK electricity industry struggles to adapt its transmission and distribution system to a new era of hyper-dynamic generation and consumption.
One of the most serious effects of the transition is the growing inability of utility 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.
Uncontrolled voltages cause electrical equipment to operate inefficiently, wear out prematurely, and trip out when safe voltage levels are exceeded. Voltage and reactive power control gaps were among the interacting factors identified after the Spanish and Portuguese outage of April 2025. Regionally inadequate voltage control systems can also prevent data centres connecting to the grid.
Grid under strain
The key issue is not just increasing generating capacity to meet growing demand. It is how the transmission and distribution system can be adapted to accommodate thousands of widely dispersed, intermittent sources of renewable energy, together with millions of EVs, heat pumps, data centres, and other fast-changing loads, in a system originally built around centralised power stations and predictable demand.
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. Efforts to fix them remain piecemeal.
This pressure is also visible in the industry response to grid connections, including work on standardised electricity connection archetypes for UK data centre projects. 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 pains
The International Energy Agency (IEA) reports that data centre electricity consumption reached about 415TWh in 2024, or roughly 1.5% of global electricity consumption, and is projected to reach just under 3% by 2030 in its base case. In high-density markets, the pressure is much sharper. Ireland’s official statistics office reported that data centres accounted for 23% of metered electricity consumption in 2025.
That puts many data centre operators in the league of significant Private Network Operators (PNOs), approaching the scale of utility Distribution Network Operators or Distribution System Operators (DNOs and 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, and more reliable service.
Automatic voltage control
Voltages in the pre-renewables era were controlled by electromechanical transformers and tap changers, which worked well 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 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 asset management
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 of 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 that 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, it 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.
About the author
Dr Vincent Thornley is managing director of Fundamentals at EA Technology, whose voltage control solutions are used by every UK electricity network operator. Fundamentals also co-founded and co-hosts the electricity industry’s Voltage Matters Forum.
