Why do data center operators choose diesel backup over cleaner microgrids?

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Operators of data centers — which consume high amounts of electricity per square foot of space — generally choose diesel backup systems over cleaner microgrids, sticking to the tried and true and believing that diesel provides the best reliability option.

data centers

Corridor of a working data center.
Photo by Gorodenkoff/Shutterstock.com

But that conservative choice yields emissions of carbon and particulates and misses opportunities to use cleaner microgrids to lower emissions and costs.

That’s the word from microgrid industry members, some of whom are just now beginning to crack the market. They say their efforts to educate data center operators about microgrids’ environmental and cost advantages are slowly beginning to pay off. And, microgrids can meet the data center industry’s requirements for reliability, the industry members say.

Data centers, which account for about 2% of US electricity use, are among the most energy-intensive building types, using 10 to 50 times the energy per floor space of a typical commercial office building.

“This sector is highly dependent upon electricity for continuous business operations and any disruption in available power can have a significant impact on reputation, loss of customers, financial losses, etc.,” said Eric Dupont, executive vice president and chief development officer at PowerSecure. “This appears to drive data centers to continue to follow their traditional and proven model of backup generation systems sequenced to operate when grid power outage occurs.”

Afraid of change?

With microgrids, data centers can reduce the high cost of energy by participating in market programs such as emergency response, demand response and curtailment programs, Dupont noted. But the industry hasn’t adopted microgrid use because it doesn’t want to disrupt its traditional model, he said.

What’s more, data center operators are less interested in resiliency than energy costs, said Tom Poteet, vice president of corporate development at Mesa Natural Gas Solutions.

And many data centers are part of a network of data centers within one company, with all the data from one center backed up somewhere else. “So as long as data is preserved, a temporary reduction in computing power may be deemed to be tolerable,” said Poteet.

To lower their carbon footprints, some data centers invest in large arrays of solar panels located off-site, rather than choose microgrids with renewable components, he said.

Added Mike Byrnes, senior vice president of Veolia North America, “The more progressive operators like Facebook, Google, Microsoft, Equinix are signing virtual PPAs [power purchase agreements] for utility scale solar and wind farms to cover their green requirements.”

Meanwhile, data centers’ diesel generators are operating more often, especially in California, releasing carbon and particulates. In the San Francisco Bay area of California, an air quality management district is concerned.

“Whenever there’s a state of emergency in the state of California, the diesel generators run. That has not gone unnoticed. The run hours are more frequent than emergency only,” said Allan Schurr, chief commercial officer at Enchanted Rock. This means that the diesel generators are not just running during outages, they also are called on to run when there’s an emergency on the grid involving low power resources.

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Concern in California

The Bay Area Air Quality Management District (BAAQMD) sent a letter to the California Energy Commission (CEC) last March about two data center buildings Microsoft proposed on 64.5 acres in San Jose. Forty 3-MW Tier 4 diesel generators would serve the buildings’ 92-MW load diesel, according to the letter.

“The Air District is concerned about the potential for any increase in emissions that could result from the project,” said the Bay Area air district. “To achieve the most health protective air quality conditions and to reach climate goals, the Air District highly recommends the CEC consider requiring the project applicant to use the cleanest available technologies and fuels possible during all phases of the project.” That would include zero-emission sources for energy and backup generation.

“Whenever there’s a state of emergency in the state of California, the diesel generators run. That has not gone unnoticed.” — Allan Schurr, Enchanted Rock

The district also said that several Bay Area data centers were using backup diesel generators for reasons other than routine testing and maintenance.

“The issue raised by the BAAQMD is that assuming limited hours per year for diesel generators (for testing, maintenance and the infrequent outage) as traditionally has been done understates the new reality of system emergencies when the state authorizes/orders diesel generators to run,” explained Schurr. Regulators should use the increased hours to evaluate environmental impacts, not the minimal testing and maintenance hours only.

“It appears 40 or more generators operated concurrently at two facilities, and one facility ran diesel generators for approximately 400 hours for nontesting/nonmaintenance purposes during this time period,” said the letter, which called for increased scrutiny of these data centers’ environmental impacts.

Schurr said that microgrids with renewable natural gas can achieve net-zero emissions, and that it’s not cost prohibitive.

“We have data to show that Tier 4 diesel might be 10 times cleaner than Tier 2, but 10 times dirtier than natural gas microgrids,” Schurr said.

cleaner microgrids

Aligned Data Center. Courtesy of PowerSecure

Data centers that use cleaner microgrids

In spite of the obstacles to convincing data center operators to invest in clean microgrids, a few data centers have moved forward with microgrids.

For example, PowerSecure installed a microgrid at the Aligned Data Centers site in Plano, Texas. The facility does use five 2.5-MW Tier 4 diesel generators. But the microgrid emits one-tenth of the particulates of conventional backup generators, says Jacob Carnemark, former CEO of Aligned Data Centers in a video from PowerSecure. He added that the microgrid’s energy efficiency and ability to coordinate with the grid during peak load times create “one of the most sustainable data centers on the planet.”

In another recent project, Enchanted Rock provided a microgrid with natural gas generators, through its partner Entergy, to the US Army Energy Research and Development Center’s supercomputing data center in Vicksburg, Mississippi. The microgrid’s main purpose is to provide power during an outage. But the microgrid can provide capacity to the grid during peak usage times, said a press release from the US Army Energy Research and Development Center.

More microgrids are on the horizon for data centers, said Bill Kleyman, executive vice president of digital solutions at Switch, a large data center operator headquartered in Las Vegas, Nevada.

“Our industry is still getting caught up on the education and the capabilities of modern microgrids, which will become more prevalent in this space. Diesel is not the fuel of the future,” he said.

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  1. Andria Odrowski says:

    I am confused about this quote, “What’s more, data center operators are less interested in resiliency than energy costs.” I haven’t worked on data centers in a few years, but resiliency/redundancy was always more important than the cost of energy. That is why the generators discussed in the article in California ran for 400 hours at one point. They would rather spend the money to run the generators and have guaranteed good power, versus brown outs or power loss. If it takes the California government pushing back on allowing diesel backup only, then they need to do it. But, the problem with that is that many companies will just go to a state that puts business before the planet.

  2. Rex Stock says:

    How is buying power from solar farms miles away from where power is being used “green”? It isn’t. Saying something is “green” is not the same as actually being “green”, as this well-written piece suggests…

    There are actually alternative diesel fuels available right now that are significantly more efficient, burn cleaner, and are “drop-in” replacements. As mentioned in this piece, natural renewable gas (the kind one gets from, say, a landfill) are better choices than status quo.

    It seems the biggest obstacle is the narrative that says data centers need hundred and hundreds of MW’s to be profitable and add customer value and the nearly task of then doing this all the right way, via microgrids. The Hyperscale narrative may very well be false. It certainly is ready for legitimate disruption.

    The real problem is the industry has not been forced to change its ways and associations and non-independent industry groups that push a narrative of “green” will not suffice much longer. If the industry doesn’t change from within, it will be forced to change by outsiders. That’s rarely a good thing.

  3. Thomas Brennan says:

    There are actually alternative diesel fuels available right now that are significantly more efficient, burn cleaner, and are “drop-in” replacements. As mentioned in this piece, natural renewable gas (the kind one gets from, say, a landfill) are better choices than status quo.
    Build refineries around the USA that can produce biofuel. Make it available at the pump and sell the benefits of using fuel that is cleaner and lowers CO2 output. Healthy for our community. This approach should be backed by government/ private investment. These diesel generator sets must be configured to run on biofuel. Our community is being negatively impacted by allowing this deisel fuel generation to continue.

  4. Joseph Calhoun says:

    Today’s propane is 98% cleaner than diesel fuel and is a near “drop in” replacement. Conventional propane is also less expensive than diesel fuel, especially when you factor maintenance costs. Use of renewable propane, a by-product of production of renewable jet fuel, is beyond net zero … it actually has a carbon intensity that is net negative.