Microsoft and Eaton Aim to Push Back on US Power Grid Woes with Data Center UPS

September 29, 2021 by Jake Hertz

Many challenges plague the US electric grid. However, once a power strain on the grid, data centers could flip the switch and help the grid instead of drag it down.

When the electrical grid was first developed and created in the late 1800s, the state of the technological world was nothing like what it is today. As time has passed and technology has developed, society has significantly increased its power consumption and put new, unforeseen strains on the grid. 

Today, these challenges continue to mount with the rapid introduction of renewable energy sources and the increased development of high-power data centers. 


A general overview of a basic grid system.

A general overview of a basic grid system. Image used courtesy of APG&E


These challenges have sparked much debate in academia and industry about how the grid can evolve to support our modern world. To this end, Microsoft and Eaton have recently released a whitepaper discussing a new concept called grid-interactive data centers. 

This article will examine the challenges facing the grid, more specifically, the US grid system, and dissect the new proposal from Microsoft and Eaton. 


Developing Challenges for the Grid: Stability 

The first major challenge that has begun to plague the US electrical grid is stability. 

One of the defining features of the electrical grid is that its frequency stays within defined limits of the nominal frequency of 50 Hz or 60 Hz. In the long term (on the order of minutes), frequency deviation is a function of the mismatch between the grid’s supply and demand; when the demand exceeds supply, the frequency decreases, and vice versa. Hence, keeping the grid stable and reliable requires matching supply and demand. 


The general power grid demand during summer and winter.

The general power grid demand during summer and winter. Image used courtesy of Let's Talk Science


In the short term (on the order of seconds), stability is a function of the ability of the grid to quickly respond to transient loads. Both of these issues are becoming a challenge due to increasing power demands from loads such as data centers. 

Adding to this issue is another challenge, decentralization.


Developing Challenges for the Grid: Decentralization 

Another factor that is causing challenges for the electrical grid is the introduction of variable renewable energy (VRE). The challenge here is twofold. 

First, the electrical grid has historically been a mostly-centralized system, where a single company will be the sole provider of electricity to an entire region. 

However, the introduction of VREs is completely changing this narrative, where individual households, solar farms, and wind farms can generate and sell a non-trivial amount of electricity to the grid. This situation can make it difficult to achieve long-term stability in the grid, as energy sources cannot be uniformly distributed or controlled. 


Example of a decentralized microgrid control system.

Example of a decentralized microgrid control system. Image used courtesy of Schneider Electric


Secondly, VREs are intermittent sources of electricity. Essentially, they vary by time based on environmental factors (i.e., the amount of sunlight or wind). This reliance further exacerbates the stability issue, along with the decentralized nature of VREs makes it increasingly difficult to achieve short-term stability, as it’s near impossible to provide fast and reliable transient responses when the energy source itself is intermittent. 

With each of these main challenges in mind, let's take a look at what Microsoft and Eaton are proposing.


Microsoft and Eaton Proposed Solution 

To address these challenges, Microsoft and Eaton proposed a new solution called grid-interactive data centers in their latest whitepaper.

The idea is that data centers already retain megawatts of backup power reserves in their uninterruptible power supplies (UPS), making them effectively hyperscale energy storage plants. Thus, by making it interactively integrate the data center’s energy storage with the rest of the grid, a term the companies call “grid-interactive UPS,” grid operators can leverage the storage to supply energy to the grid as needed. 

This system can be viewed analogously to a decoupling capacitor in an IC or PCB; the data center will be a reservoir of emergency energy for transient loads on the grid. 


Simplified UPS block diagram for data centers.

Simplified UPS block diagram for data centers. Image used courtesy of Eaton


According to the whitepaper, with the correct control algorithms, the data center’s energy storage can be seamlessly controlled while remaining connected to the power grid. This means that there’s no need to disconnect the grid or the data center from a UPS to provide demand response, the performance of both will be unaffected by the presence of the other. 

This pursuit will not only protect grid loads against voltage and frequency anomalies by providing fast responses to loads, but it would intelligently leverage the connected energy storage to manage power and the flow of energy. This would allow data centers to optimize energy usage, reduce the cost of energy, and allow higher penetration of renewables. 


Fighting Challenges for the Future 

The state of the world today, with high power data centers and increased reliance on VREs, has created some significant challenges for the electrical grid. 

Microsoft and Eaton have teamed up for their novel concept: grid-interactive data centers. While this idea is still just a concept, it seems poised to enable significant and positive change in the electrical grid as it evolves over the coming decades.

It will be interesting to see where and how this concept could be employed and if it can help shake off some of the burdens and challenges the grid faces