This overlooked piece of data center technology could hold the key to protecting power grids from disruptions


Uninterruptible power supply (UPS) systems can be found in all data centers, usually in the form of battery backups, to provide backup power for workloads to keep running, even in the event of an unexpected outage.

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Generators in data centers can play a key role in helping the local network manage some of the challenges associated with the transition to renewable energy, according to new research published by Microsoft and energy management company Eaton.

Uninterruptible power supply (UPS) systems can be found in all data centers, usually in the form of battery backups, to provide backup power for workloads to keep running, even in the event of an unexpected outage.

However, because such events are rare, UPSs spend most of their lives untouched. Data centers are therefore currently on the banks of underutilized battery banks – which is why Microsoft and Eaton are now investigating whether the buildings’ UPSs can also support the local network against anomalies and failures.

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Pumping more renewable energy into the grid adds complexity, and a particular concern is the instability generated by solar and wind power.

Conventional energy sources such as coal and gas provide the net of what is known as inertia: when the system receives a shock, their turbines can temporarily continue to rotate due to the kinetic energy of the turbine’s spin, so that no power is still generated for it. a certain period of time, even in the event of a problem. In other words, the running generators have a stabilizing effect on the grid.

Wind turbines and solar panels work differently and cannot provide inertia. Switching to renewable energy therefore also means losing the shock-absorbing advantage of traditional energy sources, making the electricity grid a lot more vulnerable to unexpected failures.

In practice, low inertia can cause hugely disruptive blackouts. In 2019, for example, a lightning strike in the UK that brought a wind farm and gas-fired plant to a standstill ultimately led to power outages and disruption to more than a million consumers, with major system failures on the rail transport network affecting commuters in London.

“Having assets that ensure grid reliability, even with low inertia, means that grid operators can allow higher penetration of renewable energy,” Janne Paananen, technology manager at Eaton, who co-wrote the white paper, told ZDNet.

One solution is to provide a so-called Fast Frequency Response (FFR), for example by supplying power directly to the grid while slower reserves respond to a fault. In other words, a short-term solution that is essentially the same as what UPSs are designed for.

“UPSs are tailor-made for that need,” Paananen says. “They can address ephemeral moments of system imbalance, and because those are short-lived, UPSs with smaller batteries are great for that.”

UPSs are already connected to the local grid, but only to draw power from them. Eaton has developed a software-based technology that the company describes as a “grid-interactive UPS,” called EnergyAware, that allows UPSs in the data center to play a dual role: protecting IT equipment, but also serving as a power source for grid operators.

The technology has already been tested and proven in several pilot projects, including at the Microsoft Innovation Center in Boydton, Virginia, where a lithium-ion battery powered UPS was equipped with Eaton’s software algorithms and controls to interact with the power grid.

The UPS successfully tracked grid signals and responded quickly by charging or discharging the battery to balance the grid and meet operator requirements for accuracy, response time, and precision.

Eaton also piloted the new UPS technology in Ireland, where the company is based, and in Finland and Norway. “But Microsoft is the first really big player to show interest,” Paananen says. “If the big bosses do it first, others will follow. It will set an example for the rest of the industry.”

With the white paper, Eaton and Microsoft hope to provide a more informed picture of the technology to data center operators who may be interested, for example by answering questions about the economics of the concept.

Paananen argues that there are no downsides to opening up data center UPSs to the net. In Scandinavian countries, for example, the grid only needs to be backed up for up to 30 seconds in the event of a failure – an amount of energy that most data centers already have in their batteries, on top of what they need for their critical load, meaning they don’t even need to invest in more capacity.

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Of course, different networks have different requirements, but contributing to the stability of the network is also an additional income stream for operators. Paananen estimates that the typical payback period will range from one to three years. In the UK, for example, Eaton’s estimates show a return of nearly £130,000 ($178,000) per megawatt allocated to grid support.

“The nice thing is that if you get a fee, it won’t cost you anything to be green,” says Paananen.

That’s not to say that only data center UPSs will solve the renewable energy inertia equation. Rather, Paananen believes that the switch to wind and solar requires an “all-as-grid” perspective, where all assets that can contribute to maintaining the grid’s balance sheet should be connected to the system.

This makes more sense than building new systems for the same purpose, but requires breaking silos in the current infrastructure. Data centers, while key to the success of the move, are therefore only part of the process.

Microsoft, for its part, seems eager to develop and execute the idea. “Data centers are at the heart of our digital economy, providing the opportunity to provide a readily available, better way to support the grid. This support helps power grids achieve higher levels of renewable energy,” said Ehsan Nasr, senior engineer of advanced data center development at Microsoft.

“Once stored energy in data center systems is harnessed to provide flexibility and optimization services, it becomes an asset with increased value, so it’s a triple benefit, for the grid operator, data center operator and the environment.”

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