Storage is the Boss for Utility-Scale Microgrid Yielding 70% Renewables

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A utility-scale microgrid that uses energy storage has slashed the use of diesel fuel and allowed for up to 70 percent renewables to serve a Portuguese Island, Graciosa.

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Graciosa project. Photo courtesy Leclanché

The microgrid is made up of a 6-MW, 3.5-MWh battery system from Switzerland-based Leclanché, about 1.5 MW of wind energy, 3 MW of solar and an existing diesel system that provides backup, said Bryan Urban, executive vice president, stationary storage solutions, for battery provider Leclanché.

The company recently upgraded an existing project — originally developed by another European company — that included the solar, wind and diesel. Leclanché added the battery energy storage and associated controls, he said.

“It was a microgrid, and it took awhile for it to be operational. Software needed to be updated and replaced,” Urban said.

What makes this utility-scale microgrid unique is the important role of energy storage, he said. The wind, solar and diesel resources all flow through the battery first, and the battery decides how to distribute the energy to the grid that supplies the whole island.

Energy storage as cog in wheel

“The battery controlling everything is quite a bit different,” said Urban. “It is controlling the resources and integrating with the grid that supplies all the power to the island.”

That’s different than what happens in many other areas where the grid is larger, he noted. For example, in California, batteries store solar during the day and release the energy at night. “The battery and solar can function independently because the solar and storage are intertied to the larger grid,” he explained. In the Graciosa project, on the other hand, the resources go to the battery first, and the battery is in control.

“The battery becomes the cog in the wheel with different types of generation capacity,” Urban said.

The company plans to replicate this microgrid project on other islands, using its own energy management system, he said. The system is software that allows the batteries to interface with numerous types of generation, including renewable energy and diesel. In this project — before Leclanché,  acquired its own software system — an energy management system from Greensmith Energy was used.

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Initially, the island was fueled solely with diesel. The project reduces diesel use by nearly 70 percent, said Urban. While on some days the island can operate at 100 percent renewable energy — depending on how much wind and solar are available — the fuel is diesel about 30 percent of the time, he said.

“This island is a great example of how to utilize multiple technologies, both wind and solar, with battery storage to reduce diesel,” he said.

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Another advantage of using a smart battery that’s in charge of the resources: It can provide frequency regulation, voltage control and other services, said Urban.

When the renewable energy flows through the battery, there’s less need to regulate the frequency, he noted.

“When power runs through the battery, there are fewer fluctuations on the grid,” he explained. “It can provide more constant and accurate amounts of power. It can control the frequency, load balancing and voltage changes.”

Islands in the Azores and across the globe are good candidates for this system, Urban said.

“This could also be utilized at commercial and industrial locations with sufficient loads where you could afford to put in solar or wind instead of diesel,” he added.

Meanwhile in PJM

In addition to the Gracio microgrid project, Leclanché recently completed the Marengo project in Chicago, a large grid-tied regulation services project in the PJM market that utilizes a 20-MW utility-scale battery.

The Leclanché battery, which is interconnected to the grid through a large utility substation, provides frequency regulation.

“The way it works is that you nominate capacity in PJM for this type of actively traded service, and you receive an electronic signal from the network to respond to either charge or discharge at different levels,” said Urban.

PJM has 70 GW of power on its network, and experiences fluctuations in generation, given that resources include solar, natural gas, hydropower, wind and others, Urban said.

“Sometimes it needs a battery to charge and absorb energy. Because battery systems can react quickly and accurately, in two second intervals, it reduces the impact of fluctuations in PJM’s resources,” said Urban.

Battery storage has boosted the efficiency of PJM’s system, he added.

A few years ago, PJM called for about 1,000 MW of frequency regulation. But when batteries were introduced, providing fast response times to calls for frequency regulation, PJM’s needs dropped to 700 MW of frequency regulation, he said.

PJM’s market provides important opportunities for battery operators to generate income — and provide significant grid efficiency improvements, he said.

“The advantage of the PJM market: It’s well defined and traded with visibility,” he said.

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  1. Willard L. Warren PE, Fellow IES says:

    What does PJM stand for?

    • Will Belfiore says:

      PJM is the shorthand for the “Pennsylvania, New Jersey, Maryland” area Regional Transmission Organization (RTO) that oversees that portion of the U.S. grid. The name stuck even though the area covered is now significantly larger than just those three states.

  2. Could someone correct the technical information involved pls?

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