Why data centres make flexibility more valuable

When people talk about data centres and electricity, the conversation usually starts with volume. How many terawatt-hours will they use? Will there be enough power? Those are fair questions, but in my view they are not the most interesting ones. As data centres grow across Europe, the questions that matter more are when electricity is needed, where it is needed, and how flexibly the system can respond. And that shift reaches far beyond the data centre industry.

The question is no longer just how much electricity

According to the International Energy Agency (IEA), data centres used around 415 TWh of electricity in 2024, about 1.5% of global consumption. In its Base Case scenario, the IEA expects that to more than double to around 945 TWh by 2030.

Those are big numbers, but still a modest share of total demand. The real impact is local. The IEA estimates that a typical AI-focused data centre uses as much electricity as 100,000 households, and that the largest ones now under construction will use 20 times as much, all through a handful of grid connections, around the clock.

That is why it helps to separate three things. Energy is how much electricity is used over time, measured in megawatt-hours (MWh) or terawatt-hours (TWh). Power is how much is drawn at any one moment, measured in megawatts (MW). Grid capacity is how much power the network can actually deliver to a given place. A country can have plenty of the first and still run short of the other two.

Timing: always-on demand meets weather-dependent supply

Data centres are among the most constant electricity users there are. They run at close to full power day and night, all year.

At the same time, more of Europe's electricity comes from wind and solar, which follow the weather rather than demand. Most of the time the two fit together without trouble. The pressure builds in specific hours: a still, overcast winter week when both wind and solar output are low, or an evening when solar fades just as demand peaks. In the Nordics, the hardest moments are often cold, windless winter days, when electric heating pushes demand up. Through all of it, large constant loads keep running.

Adding always-on demand to a system with more variable supply does not automatically cause problems. But it makes those difficult hours matter more, and it makes the ability to shift demand or supply between hours more valuable.

Location: power is not always where it is needed

The second shift is geographical. In the Nordics, much of the generation sits in the north, while much of the demand is in the south. Across Europe, the best sites for wind and solar are often far from the cities and industrial centres that use the electricity.

Data centres add a new layer. They cluster where land, fibre and grid connections are available, and a few large projects can change the picture for a whole region. Grid operators are now receiving connection requests for far more data centre capacity than will ever be built. In Sweden, for example, Svenska kraftnät had applications for nearly 7,000 MW of data centre capacity in its queue in September 2026.

New transmission lines take many years to plan and build, while data centres can go up much faster. That mismatch in timelines is one of the main reasons flexibility is moving up the agenda.

Flexibility is becoming part of the infrastructure

Grid operators are responding differently in each market, but the direction is similar. In Sweden, Svenska kraftnät offers conditional connection agreements, where a customer's power can be limited at critical times. In Finland, Fingrid now requires large new loads connecting to its grid to be able to reduce consumption when the system is under stress. Denmark has taken the most direct step: after Energinet temporarily paused new connection agreements for large customers in spring 2026, a broad political agreement replaced "first come, first served" with a priority order for new connections. Most large data centre projects would fall into the lowest-priority category, while projects that place less strain on the grid could receive priority over others in the same category.

Flexibility can come from many places: power plants that can ramp up or down, consumers who shift their use, and energy storage. Battery energy storage systems (BESS) are among the quickest to deploy. They can move consumption between hours, cap peaks, respond to price signals and, where markets allow, help balance the grid through reserve markets.

Data centres are part of this picture too. Most already have batteries in their uninterruptible power supply (UPS) systems, and some operators are exploring how that capacity could support the grid without compromising uptime.

Batteries are not a cure-all. They store hours of energy, not weeks, and they do not replace new generation or transmission lines. But as a tool for managing timing and local constraints, they are becoming hard to ignore.

Not just a data centre story

What I find most interesting is how far these questions reach. When electricity is used, how high the peaks are and how exposed a site is to price swings can matter just as much for factories, commercial properties, logistics centres and EV charging hubs.

The principle holds even where data centres are not the main driver. In the Czech Republic, the growth of solar power and electric vehicles is raising similar questions. In its FNA CZ 2026 assessment, transmission system operator ČEPS uses a scenario that assumes around 2,000 MW of installed battery storage capacity by 2035.

Not every site needs a battery, and not every business case stacks up. Load profile, grid connection, electricity contract and local market rules all play a part. But for many businesses, understanding their own timing and peak demand is becoming as important as understanding their total consumption.

That is the problem we work on at Emaldo every day: helping businesses use flexibility to lower their energy costs, make better use of their grid connection and, where the market allows, earn from supporting the grid.

Closing

Data centres are not the only reason Europe's power system is changing, but they make the change easier to see. The question is no longer just how much electricity we have. It is whether we can use it at the right time and in the right place.

Read more about what this means in your market:

• Data centres in Finland

• Data centres in Sweden

• Data centres in Danmark

• Data centres in Czech Republic