Data centers and batteries: how BESSs are changing the game

The explosion of cloud computing, generative AI, and digital services has driven up electricity consumption. data centers to levels that just a few years ago seemed like science fiction. Today, these facilities consume around 2% of the world's electricity And everything points to that figure potentially doubling before 2030, with global energy use forecasts approaching 945 TWh by the end of the decadeIn countries like the United States, where more than 5400 data centers are already operating, official projections suggest they could consume up to 12% of national electricity demand in a few years.

This explosive growth is putting existing electricity grids under immense pressure and directly contradicting decarbonization goals. Operators face a double challenge: they need guarantee virtually perfect uptime in a context of aging networks and extreme weather events, and at the same time they are obliged to drastically reduce your carbon footprint and their energy costs. In the midst of this perfect storm, the battery energy storage systems (BESS) They have gone from being a technological curiosity to becoming a strategic piece of the energy puzzle of data centers.

The new energy challenge for data centers

The volume of data we move daily, added to workloads of cloud computing, AI, and hyperscaleThis is forcing a change of scale in the global electrical infrastructure. In the US, there have already been cases where a transmission line failure has suddenly disconnected around 1500 MW of data center load, an impact comparable to losing a large generating station from the grid.

In many areas with a high concentration of data centers, they begin to appear capacity bottlenecks and long interconnection queues for new projects. In addition, current networks are experiencing more extreme events: storms, heat waves, fires… The result is an increase in blackouts, micro-outages and supply quality problemsThe average American customer suffered about 8 hours without power in 2020, and in some states total annual outages reached between 30 and 60 hours.

For a data center, even a couple of seconds without power is a catastrophe. Studies like those from the Uptime Institute place the Cost of downtime between $100,000 and $500,000 per hour in business facilities, not to mention reputational damage or contractual penalties. That's why the sector's historical obsession has been to surround itself with layers of redundancy that guarantee that The servers never shut down..

Traditionally, all of this has been resolved with diesel generator banks and lead-acid UPSGenerators have the advantage of being able to operate as long as there is fuel, but they come with a number of problems: CO₂ emissions and local pollutants, noise, the need for fuel tanks, complex maintenance, periodic testing, and above all, a startup time of several seconds which necessitates oversizing uninterruptible power supply systems.

Furthermore, many large technology companies have decided that continuing to rely on diesel goes against their environmental commitments. Microsoft has set 2030 as the date to eliminate backup diesel. Google has already tested large battery systems in data centers like the one in St. Ghislain, Belgium, to replace generators. Regulatory pressure in cities like Amsterdam and Singapore, where moratoriums or restrictions on data centers have been proposed for energy reasons, is also pushing towards a cleaner and smarter model of electrical backup.

What is a BESS applied to a data center?

A BESS (Battery Energy Storage System) is simply a large rechargeable battery bank with advanced power electronics and controlIt is capable of storing energy and releasing it at high speed when needed. In a data center, it integrates with the existing electrical infrastructure (UPS, switchboards, transformers, and even generators) to provide a power reserve that comes into action almost instantaneously.

The main difference compared to a generator is speed. While a diesel engine typically takes between 5 and 15 seconds to start up and synchronizeA modern lithium-ion-based BESS is capable of assuming the charge in less than 50 millisecondsIn practice, it behaves like a High capacity and high power UPS, keeping the servers powered without flickering in the event of any network outage or power surge.

A typical BESS for data center is made up of battery modules (LFP, NMC, LTO or other chemistries)These systems include bidirectional inverters/converters, protection systems, and control software that determines when to charge, when to discharge, and how to interact with the grid and other assets (generators, solar panels, etc.). They are no longer sized solely in MW of instantaneous power, but rather with a strong focus on... useful energy in MWh and backup duration that they can provide.

The great news for operators is that in recent years the cost of lithium-ion batteries has fallen by more than one 20% between 2020 and 2024And the massive deployment in markets like California and Texas (more than 22 GW of combined utility-scale BESS in 2024) has demonstrated its large-scale reliability. This technological maturity means that Installing BESS in data centers is no longer an experiment, but a fully industrial decision..

Key benefits of BESS in data centers

The addition of BESS brings a triple advantage that is hard to ignore: greater resilience, reduced energy costs, and a radical improvement in sustainabilityLet's look at each block in some detail and with real-world examples.

1. Extreme resilience and no-excuses uptime

In the data center business, uptime is the key metric. Here, BESS systems play a leading role in guaranteeing this. Stable, instant and high-quality energy in the event of any grid eventWhen a voltage drop, a line loss, or a total blackout occurs, the battery kicks in within milliseconds, so the IT electronics don't even notice.

Modern BESS systems achieve availabilities exceeding 99,9% Thanks to the absence of moving mechanical parts, as they are continuously monitored, the battery system offers a higher starting rate than a diesel generator, which typically has a 95% starting rate. significantly higher response reliabilityFurthermore, they help filter harmonics, spikes, and rapid voltage drops, protecting highly sensitive equipment such as servers and storage systems and network electronics.

A striking example is that of Microsoft in Swedenwhere a 16 MWh BESS with a maximum power of 24 MW has been installed in a hyperscale data center. This system provides approximately 80 minutes of backup power at full loaddisplacing dozens of diesel generators and reducing local emissions to zero during an outage. The BESS is also prepared to provide support to the regional grid, including black start capability in the event of a major disturbance.

Another case is that of Google at its data center in St. Ghislain (Belgium)where a 2,5 MWh battery was deployed to replace part of the diesel fleet. During an actual grid outage, the battery system kept the facility operational, preventing losses estimated at around 2 million in a single incident of potential downtime.

Beyond these media examples, BESS provides very concrete operational advantages: Ultra-fast response, less maintenance, less mechanical complexity and the possibility of operating as a microgrid, combined with renewables or clean energy generators to overcome prolonged blackouts. All of this translates into fewer infrastructure failures and, therefore, in More protected income and better-backed contracts.

2. Savings on the electricity bill and control of peak demand

The second major set of benefits is purely economic. A well-managed BESS allows for... peak shaving and price-based load switching, two levers that can significantly reduce the electricity bill of a data center.

The idea is simple: the system charges when the price of electricity is low (at night, during off-peak hours, or when there is excess renewable generationand discharges when electricity is expensive or when power peaks are reached that would cause the demand term to spike. Many electricity contracts penalize the maximum kW recorded per month, so smoothing out those peaks with batteries can result in savings of between 10% and 30% of the energy cost, according to studies by NREL and real cases in large data centers on the west coast of the United States.

In addition to avoiding fare peaks, a BESS allows you to participate in demand response programs and network ancillary servicesDuring periods of stress on the electrical system, the operator can temporarily reduce its grid consumption and operate using stored energy, or even feed power back into the grid if regulations permit. In return, it receives payments or credits that convert its BESS into a additional source of income or cost reduction, instead of a simple parked safe.

Regulation also helps. In the United States, the Inflation Reduction Act included a 30% tax credit for investment in independent energy storage and a production credit of $35 per kWh manufactured, which is pushing numerous manufacturers—including automotive giants like Ford, Stellantis, and General Motors—to convert production lines from electric vehicle batteries to stationary storage solutions for data centers and AIThis change is reinforced by tariffs of around 60% on Chinese batteries for storage, which improve the competitiveness of local production.

A large facility on the US West Coast that implemented a battery system to manage its load profile reported millions of dollars in annual savings and a reduction of around 15% in its energy costs. Furthermore, during a summer power outage, it was able to operate using batteries and on-site generation for several hours, avoiding soaring spot prices and receiving compensation for do not increase the pressure on a network that is already at its limit.

3. Sustainability and maximum renewable energy levels for a sector under scrutiny

The third pillar of BESS value is sustainability. Data centers have become a focus of attention for clients, investors and regulators which demand ambitious climate targets and credible plans to reduce emissions. Hyperscale operators such as Google, Microsoft, and AWS have publicly committed to operating with 100% renewable energy or, in the case of Google, with 24/7 carbon-free energy by 2030.

The problem is that solar and wind power are, by definition, intermittent. This is where BESS plays the role of the glue that makes the equation work in practice. These systems allow store the surplus of renewable generation when there is more production than consumption, and release it later during peak demand or when the renewable resource is low (night, windless days, etc.).

For large data centers, this opens the door to operating with very high percentages of real renewable energy. Apple, for example, has explained that one of its data centers in Nevada already operates with around a 80% solar energyrelying on on-site storage that shifts daytime production to nighttime. Meta, at a hyperscale data center in Sweden, calculated that combining wind power with a large BESS allows for savings of around 100,000 tons of CO₂ per year compared to a traditional diesel scheme.

Another important contribution is the direct reduction of emissions by replacing diesel generatorsWhen a facility migrates its diesel backup to batteries, emissions are eliminated each time there is a grid outage, as well as those associated with periodic generator testing, which can consume tens of thousands of liters of fuel per year just to verify that everything is working. Real-world case studies show reductions of up to 60% in the carbon footprint of a data center by combining BESS and network consumption optimization.

From a regulatory standpoint, all of this aligns with objectives such as those of the European Union, which seeks to cut greenhouse gas emissions by between 40% and 55% by 2030 compared to 1990, and includes data centers in its energy efficiency and reporting directives. As cities tighten limits on noise, emissions, and land use, being able to demonstrate that they are being used clean and quiet backup solutions such as batteries It can make all the difference when it comes to obtaining permits and licenses.

BESS versus traditional diesel generators and UPS

One of the most frequently asked questions by operators is whether battery systems can to completely replace diesel generators and classic lead-acid UPS systemsThe short answer is that, for most real-world scenarios, yes, although with nuances and clever hybrid designs.

If we compare a BESS with a diesel generator set, the only clear advantage of diesel remains the potentially indefinite autonomy As long as fuel is available. In everything else—response speed, efficiency, maintenance, noise, emissions, integration with renewables, and revenue-generating capacity—the scale tips in favor of batteries.

In practice, the vast majority of power outages suffered by data centers last less than two hoursAnd statistics show that even in states with more vulnerable infrastructure, the aggregate annual duration of outages is measured in tens of hours, not consecutive days. This opens the door to designs where the BESS covers with ease almost all incidents and generators (ideally cleaner or fewer in number) are only used in extreme long-duration scenarios.

Furthermore, the capacity of a BESS is completely scalable. If a data center wants to guarantee 4, 8, or even 12 hours of backup at full load, it can install the necessary energy in MWh, provided it has the space and budget. Storage projects already exist for long duration (8-12 hours) These are underway in various markets to meet reliability requirements, and technologies such as flow batteries or liquid metal batteries are being explored that promise to further reduce the cost per kWh stored for many hours.

When we compare BESS to a classic UPS, things are different. BESS acts as a next generation UPS with greater autonomy, more intelligence, and the ability to interact with the grid. While the traditional UPS's sole purpose is to provide a few minutes of power to cover the generator startup, the BESS can extend that backup. actively manage energy, participate in electricity markets and optimize the daily operating cost of the center.

However, the data center sector is historically very conservative when it comes to technological risk. The leap to lead-acid to lithium-ion batteries This has been done progressively, prioritizing chemistries with a good safety track record, such as LFP, and placing great emphasis on battery management systems (BMS), early fault detection, and risk compartmentalization. Emerging technologies such as nickel-zinc or sodium-ion They generate interest, but adoption usually begins with well-defined pilot projects and only moves into the "core" of the infrastructure once they have accumulated years of field experience.

What batteries are used, packaging, and technical priorities

Regarding specific battery technologies, the most prevalent solutions today are those of lithium ions type LFP (lithium iron phosphate) due to their good combination of cost, thermal safety, and lifespan. However, in applications requiring very high power density, there is interest in chemistries such as NMC/Gr or NMC/LTO configurations, capable of deliver or accept extremely high powers for short periods and withstand thousands of intense charge and discharge cycles. Learn more about the materials that drive these chemistries It can help to understand why certain technologies dominate the market.

The discussion of whether it is more important power density or energy density It depends on the use case. In traditional data centers where BESS is primarily used for backups lasting from minutes to a few hours and for peak shaving, specific power (kW per rack or per module) and millisecond response time are usually more important. In systems where storage is also used to shift large volumes of renewable energy from one time to another, energy density (kWh per square meter or per kilogram) and cost per kWh stored become more critical.

Regarding packaging, modular solutions are commonly used in rack, cabinet or container formatsIn technical rooms, batteries can be integrated into racks compatible with the existing infrastructure, while for large capacities, prefabricated containers are used that connect almost like an energy-related "Lego" set. There is also a trend toward integrating batteries closer to the power electronics and, in some cases, even considering... distributed architectures at the row or rack level of ITalthough the latter is less widespread in large-scale projects.

Other theoretically promising technologies, such as flywheelsThey haven't quite taken off in data centers for several reasons: they need space, they have mechanical losses, they require a specific infrastructure, and above all, They do not offer long-term storage and energy management capabilities which batteries do allow. They still have their niche for very specific high-instantaneous power applications, but the bulk of investment in the sector is being channeled towards electrochemical solutions.

In terms of requirements, many new data centers set a minimum requirement of having between 1 and 15 minutes of battery life to cover the transition to other sources (if any) or to tolerate frequent micro-outages. The most advanced designs now start at scales of tens of minutes to a few hours, and operators increasingly value power flexibility. adjust actual autonomy with load reduction strategies prioritizing critical loads over less essential services.

In parallel, the industry is shifting from the classic "hardware and more hardware" approach towards an approach where the key lies in the energy asset management softwareEnergy-specific Asset Performance Management (APM) platforms—such as those that rely on advanced analytics and AI, like Delfos solutions—allow you to maximize your BESS investment: they optimize the charging/discharging strategy, predict maintenance needsThey detect anomalies before they escalate and coordinate the operation of batteries, generators and renewables in real time.

This entire movement is part of a broader transformation of the energy ecosystem. The slowdown in demand for electric vehicles in the United States, coupled with the continued existence of very generous incentives for stationary storageThis is causing several automotive battery manufacturers—including Ford in Kentucky, Stellantis, and Samsung SDI in Indiana—to redirect a significant portion of their production capacity toward energy-efficient power systems (ESS) for data centers and AI infrastructure. In parallel, other energy-intensive sectors, such as cryptocurrency miningThey are converting facilities to house AI data centers, with the potential to free up between 10 and 15 GW of electrical capacity if all US bitcoin mining farms were transformed.

In this context, storage solutions like BESS cease to be a "nice extra" and begin to play a central role in the decarbonization of the electricity system and containing the escalation of energy costsData centers are no longer just intensive energy consumers: through grid stabilization, greater renewable penetration and advanced demand management, they are becoming active players in the energy transition.

The practical conclusion for any operator is clear: investing in advanced industrial batteries and intelligent energy management platforms makes it possible to achieve that sought-after combination of Maximum uptime, controlled energy costs, and much more sustainable operationsIn an industry where every millisecond of downtime counts and where the demands of customers and regulators are constantly growing, integrating BESS into the power architecture is no longer a technological whim, but a strategic decision that makes the difference between falling behind or being prepared for the next decade of digital growth.

Related article:

New 80 Plus Ruby Power Supply Standard: Efficiency, Implications, and Differences

Isaac

Passionate writer about the world of bytes and technology in general. I love sharing my knowledge through writing, and that's what I'll do on this blog, show you all the most interesting things about gadgets, software, hardware, tech trends, and more. My goal is to help you navigate the digital world in a simple and entertaining way.