Tim Foster, Director of Energy for Business at Conrad Energy, argues that the ‘diesel-first’ redundancy model is becoming a commercial and resilience risk – and that hybrid renewables-plus-storage can now outperform it on uptime, flexibility, and cost certainty.

Data centre demand and development will increase again this year, with CBRE predicting 2026 will be the second-highest year on record for new data centre supply. To keep up with this growing demand, the sector should prioritise integrating renewable energy solutions in place of the current over-reliance on fossil fuels.

Historically, diesel has been considered the optimal source of energy for data centres, an unmatched answer to the industry’s complex requirements. However, as innovations in renewable technology continue, the benefits diesel has provided can now be equalled – and, in fact, surpassed in terms of resilience, flexibility and cost certainty.

Data centres can employ hybrid models of resilience to boost operational efficiency whilst reducing harmful emissions, and these bespoke solutions are becoming increasingly accessible. Going beyond simply a consistent throughflow of power, renewable energy can be optimised to be flexibly stored, generated and used in line with localised needs.

New options on the table

The challenging combination of 24-hour uptime, high-density loads and growing demand for power makes the energy needs of a data centre extremely complex. So naturally, it’s essential that reliable, stable energy sources are utilised.

However, growing instability in the grid and increasing constraints on traditional power sources mean the industry can no longer rely on a “diesel-first” redundancy model to ensure reliable supply. Pressure is mounting for providers to respond to ESG targets and reduce fossil fuel usage, not to mention the rising costs these fuels are demanding. Grid stability can also be problematic. Whilst the Planning and Infrastructure Bill pledges to streamline grid connectivity and introduce advanced storage mechanisms, in the short and likely even medium term the grid will still be overburdened. This means delays to connections for new data centres, and the risk of blackouts or brownouts will remain.

Until recently, it hasn’t been possible to rely on renewable energy as an alternative to traditional sources. With fluctuations in generation capacity, particularly in a country where weather conditions are temperamental at the best of times, renewables have sometimes been perceived as a precarious avenue not worth exploring.

But now, advances in renewable energy supply, storage and stability mean utilising this energy has become not just an operational possibility, but a necessity.

A hybrid solution

In practice, this means a layered energy stack combining behind-the-meter renewables, battery storage, flexible grid interaction and lower-carbon backup fuels.

These help safeguard centres’ energy plans against grid volatility, offering valuable supply stability. Power Purchase Agreements with suppliers and installers of behind-the-meter energy can also cover capex costs and lock in a guaranteed price for a fixed length of time. This adds cost certainty to the benefits, and bypasses non-commodity charges associated with importing from the grid.

These energy assets also make flexibility models and markets accessible to data centres. For example, to make the most of renewably generated energy, data centres can install sophisticated lithium-ion battery systems to store surplus energy for deployment at a later time. This creates another buffer against wider system issues and helps maintain a continuous power supply. Alongside this, centres can also choose to sell excess energy back to the grid for additional revenue.

These models are no longer promising theories – hyperscale operators are already trialling renewable integration. For instance, some are seeing success using hybrid solar in tandem with battery microgrids and low-carbon backup fuels. Combined with emerging hydrogen-ready systems, these set-ups are supporting uptime with reduced emissions.

Giving data back to data centres

The increasing sophistication of renewable and hybrid energy systems is also transforming how data centres understand and manage power consumption. High-resolution, half-hourly data provides operators with unprecedented visibility over when and how energy is generated, stored and used.

This insight allows data centres to optimise operations in real time, align demand more closely with renewable supply, and demonstrate verifiable renewable usage to customers, investors and regulators. As scrutiny of sustainability claims intensifies, access to auditable, time-matched energy data is fast becoming a strategic advantage rather than a reporting nice-to-have.

The ripple effect

By adopting these solutions, data centres can strengthen resilience across every aspect of their operations. Greater predictability and control over energy supply underpins both mission-critical data processing and the everyday functions that support it, from cooling systems to lighting. By insulating themselves from the vulnerabilities of the traditional grid, operators can safeguard uptime while enabling long-term development and expansion.

The benefits also extend beyond individual sites. For each data centre that pursues resilient, low-carbon growth, there is less pressure on the over-constrained grid. This not only supports grid stability, but also benefits those users who remain more dependent on centralised supply.

Deploying renewable energy assets therefore delivers a clear environmental dividend, while simultaneously responding to growing commercial and regulatory pressure. In this way, sustainability becomes not a trade-off, but a practical and strategic advantage.

Unrelenting demand

Government analysis has found that although data centre capacity could rise to between 3.3 GW and 6.3 GW by 2030, this still may not be sufficient to meet consumer demand. In light of this, innovation that can accelerate and support data centre operations and expansion must be embraced. The next phase of data centre growth will be defined not by diesel redundancy, but by how quickly operators embrace renewable-led, flexible resilience. The time to act is now.