Is hydrogen the best long term back-up for data centers?

When we’re surfing the net or posting on social media, we rarely consider what it’s costing in energy terms. But the data centers that process our online activity are voracious consumers of electricity. Therefore, as they grow in number and capacity, their consumption is only likely to grow.

For the most part, data center operators are committed to decarbonization and a pathway towards net zero. Most data centers already rely on renewable electricity for their primary power supply through the use of Power Purchase Agreements. But the standard solution for power generation during their maintenance periods (and extremely rare power outages) is not so low-carbon. When they need to switch off the main power, data centers power up their suite of on-site diesel generators.

In a future aimed at achieving net-zero emissions, the gradual elimination of diesel and other hydrocarbons becomes imperative. Consequently, data centers must seek a sustainable backup solution—one that eradicates emissions not only during routine annual maintenance and testing but also in the less probable event of a power system failure. Our examination of the main alternatives confirms the potential for hydrogen to play a part in a low-carbon future for data centers – specifically, low-carbon hydrogen for energy storage.

The hydrogen promise

Hydrogen burns with no carbon emissions. It is already being adopted as a fuel in industrial production, and new technologies for low-carbon hydrogen production and power generation are under development. Hydrogen is a solution for the medium-term future. Its adoption today by data centers would present challenges: many would require several tube trailers of hydrogen a day to keep them running in the event of a grid outage. Storage of hydrogen on-site in the form of compressed gas would demand a large spatial footprint; its storage as a liquid would demand significant additional energy.

But the viability of hydrogen will increase greatly in the coming years, as transportation and storage technologies are further developed and adopted. As countries develop their hydrogen strategies, we’re likely to see it becoming cheaper to implement at scale, reducing the capital expenditure required for data centers to make the switch.

Short-term alternatives

In the shorter term, we are seeing some data centers move to biofuel alternatives to diesel to drive their on-site turbines, principally hydrotreated vegetable oil (HVO). HVO has a similar chemical composition to diesel and demands little or no adaptation of equipment. It has the capacity for storage and utilization for a period of up to ten years, requiring less demanding on-site maintenance when contrasted with diesel, which necessitates polishing systems to maintain stored fuel for a similar duration. Additionally, it has the potential to reduce emissions by as much as 90%. The main drawback to its use is that the preferred source for HVO production is palm oil, a known contributor to poor land and forest management, and some countries and manufacturers have now pledged to ban palm oil from their products.

Other alternatives to diesel exist, such as compressed air energy storage (CAES), flywheel energy storage (FES), and battery energy storage systems. Each of these options presents challenges and opportunities for data centers. Committing to a palm oil-free HVO offers operators the chance to instantly reduce their emissions with minimal extra investment needed in equipment. But it is no long-term solution – rather, a stopgap while the hydrogen-as-fuel industry continues its rapid development.

Implementing hydrogen

So, how exactly would hydrogen-based power generation work? We foresee a model in which hydrogen is used as an energy storage medium. While hydrogen could power industrial processes and commercial vehicles, large energy-users such as data centers will draw on stored hydrogen to fuel electricity generation.

This would require data center operators to invest in power generation equipment that could run on the new fuel. Currently, the industry supply chain is in the process of deploying hydrogen turbines that can effectively utilize 100% hydrogen, at scales that could be suitable for resilient data center standby configurations. Anticipated developments include the introduction of higher-capacity turbines over the next decade. Additionally, exploring alternatives, such as incorporating hydrogen derivatives like ammonia in combustion turbines or choosing fuel cell electricity production over combustion, could reveal potential avenues for widespread data center deployment.

A potential model may see data centers produce their own hydrogen, too, taking excess renewable-generated electricity to produce low-carbon hydrogen via a small-scale, on-site electrolyzer. This would then be stored in a facility owned by the data center operator and drawn on to generate power when required. Any excess hydrogen could potentially be exported to the market and provide a source of revenue.