Alan Dunne, Managing Director, UK and Ireland at Aggreko UK, argues that gas has a time-limited but important role to play in helping data centres bridge the gap between today’s power constraints and tomorrow’s decarbonised energy system.

Across the UK and Europe, data centre growth is increasingly constrained not by demand, capital, or ambition, but by access to reliable power. Grid connection queues now stretch into years, in some cases well into the late 2030s, while the cost and complexity of securing capacity in the right locations continue to rise. At the same time, operators face mounting pressure to decarbonise operations and align with increasingly stringent corporate and regulatory net zero targets.

Renewable generation is expanding rapidly, but intermittency, local grid constraints, and long permitting timelines mean that, for many sites, a fully decarbonised power supply is not yet viable at the point when capacity is needed. For developers and operators trying to balance speed-to-market, resilience, and emissions reduction, this creates a practical challenge rather than an ideological one.

It is in this gap that gas has a clearly defined, transitional role. It is neither a long-term destination nor a legacy technology being defended. Its value lies in acting as a flexible bridge, enabling data centres to come online, operate reliably, and scale IT loads while grid infrastructure and low-carbon generation mature. Whether gas operates as interim baseload, backup, or flexible generation depends on site-specific conditions, but its primary contribution over the next five to 10 years is as an enabler of progress rather than an end state.

Gas as a flexible bridge, not a default baseload

For most data centre operators, gas is increasingly positioned as dispatchable, flexible capacity rather than simply as a permanent baseload. Modular gas generation can be deployed in a matter of months, and in some cases weeks, compared with grid connection timelines measured in years. This speed matters, particularly as AI-driven workloads accelerate demand in markets where infrastructure is already constrained.

Equally important is gas’ role in supporting higher penetration of renewables. Wind and solar outputs vary by hour and season, and while battery energy storage systems provide fast response, they are not yet designed to cover prolonged gaps on their own. Gas generation can ramp up relatively quickly to maintain continuity of supply, allowing operators to maximise renewable usage without compromising uptime.

In locations where grid capacity is insufficient or unreliable, gas may still operate as temporary baseload. Over time, this role should diminish as grid reinforcements progress and renewable supply increases. Technologies such as carbon capture, utilisation and storage could further reduce the emissions impact of gas-fired generation, although their relevance will depend on policy, infrastructure, and market maturity.

Backup power is also evolving. Diesel is facing growing regulatory and environmental pressure. In hybrid configurations, gas paired with battery storage may offer a lower-carbon alternative, with batteries providing instantaneous response and gas supplying power during extended outages. This approach can improve resilience while reducing reliance on traditional diesel-based strategies.

Designing hybrid power systems in practice

Hybrid systems that combine gas, batteries, renewables, and grid connections require careful design and operational planning. There is no universal template. Each site must be assessed based on grid availability, renewable resource potential, land constraints, fuel access, and operational priorities such as capital cost, operating cost, deployment speed, and emissions performance.

Modularity is a defining principle. Gas generation, battery storage, and renewable assets should be deployed in scalable blocks that can be added, reduced, or repurposed as IT loads evolve. This staged approach avoids over-provisioning on day one and reduces the risk of stranded assets as energy markets and technologies change. Fuel flexibility also matters. Multi-fuel-capable generators can provide resilience against supply constraints, support future decarbonisation pathways, and utilise virtual pipelines such as LNG and LPG where a gas connection is not in place.

Control systems sit at the centre of effective hybrid operation. Advanced energy management systems and SCADA platforms are required to coordinate power flows between on-site generation, storage, and the grid. Dispatch decisions increasingly need to consider not just availability but energy price signals, grid carbon intensity, and real-time load profiles. For sites operating in island mode, robust controls are essential to maintain voltage and frequency stability and to manage seamless transitions between power sources.

From a resilience perspective, hybrid systems diversify risk. Batteries deliver immediate ride-through, gas provides dispatchable capacity, and renewables reduce overall emissions when available. Many sites may also be able to participate in demand response or ancillary service markets, improving project economics while supporting wider grid stability. Black start capability – the ability to restart independently of the grid – is also often a requirement for mission-critical infrastructure.

Operational complexity should not be underestimated. Hybrid systems involve multiple dynamic assets, and advanced monitoring and predictive maintenance tools are important to anticipate faults, optimise maintenance schedules, and avoid unplanned downtime.

Emissions, efficiency, and the full picture

Decisions about hybrid system design inevitably involve trade-offs between cost, resilience, and emissions. These trade-offs should be evaluated using realistic operational scenarios rather than idealised assumptions. Operators need to consider the full emissions picture: direct emissions from on-site generation (Scope 1), emissions associated with purchased electricity (Scope 2), and embodied emissions from equipment and construction (Scope 3).

Waste heat recovery can materially improve this balance. Combined heat and power or trigeneration systems allow exhaust heat from gas generation to be reused for cooling or heating, improving overall energy efficiency and reducing the effective carbon footprint of the site. In many cases, this is easier and more cost-effective to integrate at the design stage than to retrofit later.

Common pitfalls and lessons learned

Experience across the sector highlights several recurring challenges. On-site gas generation is often assumed to be straightforward, yet permitting can be complex, particularly in urban or environmentally-sensitive locations. Early engagement with regulators and a clear understanding of local requirements are critical, although temporary or modular solutions can reduce complexity.

Lack of fuel flexibility and overly rigid asset sizing can limit future options. Similarly, treating gas, batteries, and renewables as separate projects rather than a single integrated system can lead to inefficient dispatch and higher emissions. Operational complexity is frequently underestimated, reinforcing the importance of advanced controls and automation.

Grid interconnection remains relevant even for decentralised sites, whether for redundancy or export. These connections still involve technical and procedural hurdles that need to be addressed early. Finally, focusing narrowly on upfront capital cost risks overlooking the broader value of time to market, resilience, grid service revenues, and long-term operational efficiency. Total cost of ownership provides a more realistic basis for decision-making.

Building flexibility into the future

Future flexibility should be treated as a core design requirement, not an afterthought. Modular infrastructure allows capacity to scale with IT loads and enables the integration of emerging technologies as they mature. Adaptive energy management systems can respond to changing market conditions, energy mixes, and regulatory pressures.

Strategic site selection also matters. Proximity to gas infrastructure and strong renewable resources can significantly reduce future integration costs.

A pragmatic path forward

The path to net zero for Europe’s data centres will not be linear. Over the next five to 10 years, gas is likely to play a time-limited but important role, primarily as a flexible bridge where grid capacity and renewable availability lag behind demand.