Optimising energy for UK data centres: grid, hybrid, and microgrid approaches

Understanding Data Centre Energy Challenges

As data centres scale to meet accelerating AI, cloud computing and digital infrastructure demand, one of the earliest and most consequential decisions is how they connect to the UK energy system and electricity grid.

I used Gridcog to model and compare some alternative approaches for supplying energy to a hypothetical hyperscale 100MW data centre located in Slough in the UK.

Option 1: Fully grid-supplied energy

A fully grid-supplied approach, modelled at £1.9 billion over 15 years, is operationally straightforward but often difficult in practice. A shortage of available electricity grid capacity, long lead times for grid connection approvals, and high upfront infrastructure costs require operators to consider alternatives that reduce dependence on the grid.

Option 2: Smaller grid connection with onsite thermal generation

Adding on-site firm generation for primary energy supply, and not just for back-up power, is gaining significant traction across the UK data centre sector. Here we’ve modelled a hybrid configuration combining a reduced grid supply with a 50 MW gas genset. This reduces lifetime costs to £1.79 billion, whilst also easing pressure on the local electricity network.

Although gensets carry carbon and fuel price volatility risks, they provide a practical buffer where grid reinforcements are slow, expensive, or uncertain, helping operators secure power earlier and with more control over project delivery timelines.

Option 3: Smaller grid connection with onsite renewables, battery storage and thermal generation

A more transformative option is a microgrid-style energy portfolio of solar, wind, battery storage, grid import, and genset capacity. This integrated configuration reduces whole-life cost to £795 million and mitigates grid connection risk by supplying a large proportion of energy onsite.

The final asset sizes are BIG and definitely won’t be everyone’s cup of tea, with 124 MW of solar, 259 MW of wind, and 70 MW of storage, but it illustrates how distributed and diversified energy generation can both decarbonise operations and materially reduce reliance on costly grid upgrades.

Why Data Centres Must Rethink Energy Strategy

Data centres are no longer simply buying power; they’re required to actively participate in addressing grid congestion and connection constraints, either by reducing their reliance on the grid or by offering significant demand flexibility during “system stress” events.

If you’re a data centre developer, or a renewables project developer looking to secure long-term offtake agreements from data centre owners, and need some help understanding your options, then hit up the Gridcog team.