Microgrids Take Major Role for Reliability, Resiliency

An array of technologies, both thermal and renewable, are being used in the design of microgrids, supporting distributed power generation across several sectors.

The use of microgrids to provide reliable power for critical infrastructure is growing, and these off-grid installations also are becoming more prevalent as part of commercial and industrial (C&I) enterprises and residential neighborhoods. Early adopters of microgrids included healthcare facilities such as hospitals, along with data centers, government buildings, and other facilities at which reliability and resiliency of the electricity supply are essential. Today’s microgrid users also have recognized how the use of distributed energy resources (DERs) supports financial and sustainability benefits. Microgrids are being deployed in remote locations to provide electricity to areas far from the traditional grid. They’re being built on military bases, and also energizing port operations, college campuses, office complexes, and more. Microgrids have become the development of choice for groups looking to generate their own power, and improve the reliability, resiliency, and efficiency of their electricity supply. “Microgrids are emerging as a pivotal component of a decentralized energy future. They offer a solution not just for individual buildings, but for entire communities and municipalities,” said Bala Vinayagam, senior vice president of Microgrid Line of Business at Schneider Electric. “Community microgrids address diverse energy needs, from localized production and distribution to enhanced resiliency for critical infrastructure. The scalability of microgrids allows them to cater to both individual and multi-site applications, fostering collaboration across regions. This interconnected approach promises a more resilient, sustainable, and decentralized energy landscape for the future.”

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The technologies being used in microgrids continue to evolve. Some installations include solar photovoltaic (PV), or solar PV or wind energy paired with energy storage (Figure 1). There are systems utilizing not only renewable energy by also diesel- or natural gas–fueled generators. Some discussions today touch on nuclear power as a generation source. The use of microreactors, or small modular reactors, would support the scalability of microgrids. [caption id="attachment_220347" align="aligncenter" width="740"]

1. Technologies for microgrids include solar and wind power, and today many installations are incorporating energy storage. Source: Shutterstock[/caption] “Most microgrids still follow a ‘traditional’ architecture in which all or nearly all of the grid-forming capability is on a single electric power circuit [bus],” said Mark Siira, Institute of Electrical and Electronics Engineers (IEEE) Chairperson of Standards Coordinating Committee 21. Siira told POWER, “However, we’re seeing an increasing number of microgrids being built around existing distributed resources, usually with added energy storage. This increases a microgrid’s flexibility and resilience benefits. It is thought that the data center industry may begin adopting microgrid technology through the implementation of renewable sources and energy storage in order to power energy-intensive data centers.”

Hardware, Software, and Control

Siira noted technology upgrades that enable microgrids to perform multiple services in addition to supplying backup or supplemental power. “Larger- scale microgrids can be used by utilities to supplement weak or unstable electric grids, such as those on an island, and are being considered for such locations,” he said. “There is also a growing number of equipment suppliers for microgrid controllers, some of which are becoming very technologically advanced. A key to this integration includes reducing the cost of the communication channels and also cybersecurity, which is critically necessary in systems such as these that rely on high-speed, ‘real-time’ communications.” Siira told POWER: “In the industry, we are also seeing the trend of an increasing number of microgrids that cross the distribution-transmission boundary. For example, there are grid-forming assets that are connected to a section of a radial sub transmission line that are feeding multiple substations, some of which may host distributed energy resources. This configuration crosses the boundary between IEEE 1547 [Interconnection Standard] and IEEE 2800 [Transmission Interconnection], and between the NERC [North American Electric Reliability Corp.]-jurisdictional and non-NERC-jurisdictional ... with this, there is a need to address these kinds of systems in official standards. “For example, there was a revision of IEEE 1547 in 2018 that made the requirements clear for the interconnection of DER systems, not just DER units. Additionally, the IEEE 2030.4, 2030.7, and 2030.12 revisions have added clarity on microgrid interoperability. There is also an upcoming IEEE 1547.4 revision that will add clarity for islanded systems.” Advanced microgrids enable power generation assets to keep the local grid running even when the larger grid experiences interruptions, or in remote areas where there is no connection to the larger grid. Advanced microgrids also can allow local assets to work together for cost savings, to extend the duration of energy supplies, and to produce revenue via market participation. Much of the advancement has been in both hardware and software upgrades for microgrids, looking at how installations can integrate with the traditional grid, and studying management and control systems. “Real-time, autonomous control of local energy resources is a fundamental requirement across a variety of microgrid market segments [such as distribution, military, community, C&I, and residential],” said Nick Tumilowicz, director of Product Management, Distributed Energy Management, at Itron. “Grid edge intelligence solutions enable this functionality by providing grid-aware control of DERs, both when grid-connected, and for resilience measures, when the grid is down. Additionally, the next level of advanced metering infrastructure [AMI]—distributed intelligence [DI]—offers an embedded disconnect that serves as a grid-islanding device while providing utility distribution system operations visibility into customer operations behind the meter during an outage.” Tumilowicz continued: “Backup power, in the form of islanded, grid-forming local generation comes in a variety of shapes and sizes. Utility and customer decarbonization goals, along with the location of the microgrid, often dictate fuel availability and economics in the system design. Backup power generation via a grid-forming device is a fundamental component of a self-contained microgrid. This can be accomplished through a variety of power generation sources including fossil backup gen-sets, renewable-based fuel generators [hydrogen fuel cells], battery energy storage systems [BESS], and more. It is key to recognize the technology readiness level of commercial battery energy storage deployed across the transmission, distribution, and customer-connected grid.” Tumilowicz added, “Visibility and control features are provided to BESS in two general ways: (1) direct, local, and in real-time via DI; and (2) cloud-connected, low-latency communication. While the latter can provide value to aggregations across the grid for high-level event-based services, the demonstrated value of DI providing real-time, autonomous direct-to-DER control offers sub-second closed control loop capabilities that both grid operators and customers require to protect assets like grid transformers to customer main distribution panels. This connectivity via industry standards like IEEE 2030.5 provides access to full functionality of bi-directional, four-quadrant power conversion systems like BESS, serving as both a generator and a load. Services like energy time shift, PV self-consumption, autonomous load following, volt-watt, volt-VAR [volt-amp reactive], frequency, and droop curves can be extracted to support both grid reliability and customer resilience.”

Microgrid Consortium

The National Rural Electric Cooperative Association (NRECA), the U.S. trade association representing about 900 local electric cooperatives, earlier this year said the organization and a consortium of seven electric co-ops were selected to receive more than $45 million in funding from the Department of Energy’s (DOE’s) Office of Clean Energy Demonstrations Energy Improvements in Rural or Remote Areas program. The NRECA said building a consortium allows smaller co-ops to work together to submit competitive applications for infrastructure funds, in this case, in support of a project to deploy microgrids to improve grid resilience and electric supply reliability in seven rural areas in the U.S. The NRECA said the participating cooperatives also will share information about the microgrids with other electric co-ops. “This funding is an important step as electric co-ops work to improve access to affordable and reliable energy in rural America,” said NRECA CEO Jim Matheson. “By deploying microgrids in communities across the country, co-ops are exploring new ways to keep the lights on and meet tomorrow’s energy needs.” The seven consortium participants are:

• Anza Electric Cooperative in California.

• Blue Ridge Energy in North Carolina.

• Flathead Electric Cooperative in Montana.

• Minnesota Valley Electric Cooperative in Minnesota.

• Missoula Electric Cooperative in Montana.

• Trico Electric Cooperative in Arizona.

• Volunteer Electric Cooperative in Tennessee.

The trade group said examples of the anticipated impact from the microgrid projects “include the potential for annual electricity savings of up to $400,000 in the town of Decatur, Tennessee, and an up to 70% reduction in power outages in Cooke City, Montana.” Anza Electric in California (Figure 2) is in a high-desert fire-prone region, and the utility knows the importance of microgrids. The co-op back in 2017 turned to a microgrid to help solve issues caused by public safety power shutoffs, or PSPS—something utilities in multiple states now use as part of wildfire mitigation programs during extreme weather events so their equipment does not spark a fire. The co-op, which was dependent on Southern California Edison for its power, was shut down twice in 2017; a microgrid provided a solution to the challenge of maintaining a reliable power supply. The utility had relied on portable diesel-powered generators to produce electricity when grid power was not available. [caption id="attachment_220349" align="aligncenter" width="740"]

2. Anza Electric Cooperative in California’s southwestern Anza Valley is one of seven co-ops in a group led by the National Rural Electric Cooperative Association (NRECA) that is receiving funds from the U.S. Department of Energy (DOE) to build a microgrid. The DOE program is designed to support electricity reliability in rural communities. Courtesy: Victoria A. Rocha / NRECA[/caption]

Serving Commercial and Industrial Customers

Schneider Electric and Mainspring Energy at the CERAWeek event earlier this year said the companies will partner to offer a new hybrid-energy technology, which combines Schneider’s EcoStruxure Microgrid Solution with Mainspring’s Linear Generator. The companies said the combination “will provide power and fuel-flexibility as well as much needed energy resiliency for commercial and industrial customers.” The Mainspring Linear Generator has the ability to run on, and seamlessly switch, among various fuel types, including renewable options such as biofuels, green ammonia, and green hydrogen. That’s important for microgrid operators that want to decarbonize while also supporting power resilience during extreme weather events. It will enable users to generate electricity onsite, and operate in parallel to the power grid, or independently from the grid when needed. The companies specifically noted data centers and healthcare facilities as potential users, as it will support critical operations and reduce carbon emissions. It also will allow users to switch among multiple fuel options without the need to retrofit. “Commercial and industrial facilities are dealing with increasing demands for electricity,” said Jana Gerber, president of Schneider Electric North America Microgrid. “At the same time, organizations needing power have decarbonization goals. The Mainspring Linear Generator has the potential to serve a vital role in the transition to net zero. Customers are provided with a pioneering microgrid solution that can generate onsite power, adapt to an evolving grid landscape, and help them meet their decarbonization goals.” “We designed the fuel-flexible Linear Generator so that as clean fuels become increasingly available and cost-effective, organizations of all kinds can capitalize on them without having to replace or retrofit equipment,” said Shannon Miller, Mainspring CEO and founder. “We’re thrilled to be partnering with Schneider Electric, a leader in sustainability and microgrid solutions, to meet the evolving energy needs of our commercial and industrial customers while helping work towards a zero-carbon grid.” Vinayagam told POWER, “Trends in microgrids are representative of the increasing sophistication and functionality of these systems. They are becoming a solution to create more resilient, sustainable, and efficient energy systems. Artificial intelligence [AI]-powered optimization of the system is a main component of technological advancement of microgrids. AI is being utilized to generate intelligent predictions using consumption patterns, tariff and pricing signals, weather, and more. This offering allows for easy decision-making around when to consume, store, and discharge batteries, or even sell back energy to the grid.” Vinayagam said, “Schneider Electric’s EcoStruxure Microgrid Advisor is the software built into Schneider Microgrid systems to perform this either onsite or in the cloud. In addition to the system’s technology, virtual power plants are emerging as an ideal approach to aggregate DERs to benefit from participating in wholesale electricity markets. Today, more options to advanced energy storage, efficient and affordable lithium-ion, vehicle-to-grid technology, and a more inclusive and diverse array of DERs are enabling microgrids to become more robust systems. Standardized designs, like EcoStruxure Microgrid Flex, are leading the way in terms of how these systems are designed, built, and delivered. With more standardization comes more capability for faster, simpler applications.”

Model Microgrid Projects

Several microgrid projects are notable for their location, as well as their innovation, and have been touted as model installations. PIDC, Philadelphia’s public-private economic development corporation, partnered with Ameresco on a small natural gas–fired peaking plant that serves as the anchor for a microgrid at the city’s Navy Yard. The Pittsburgh International Airport is known for being the first airport in the world with a microgrid that’s powered by a combination of solar energy and natural gas. Groundbreaking was held in April of this year for a microgrid in California to benefit a Native American community. The project, funded by a $32 million state grant, “will support energy sovereignty and sustainable economic growth” for the Paskenta Band of Nomlaki Indians, according to the office of California Gov. Gavin Newsom. The microgrid will include 5 MW of solar power generation and 15 MWh of long-duration energy storage. It is sited at the tribe’s Rolling Hills Casino and Resort in Corning, in Tehama County north of Sacramento and south of Redding. The money, one of the largest state grants ever awarded to a Native American tribe in California, for the installation comes from the California Energy Commission’s Long-Duration Energy Storage Program, part of the Newsom administration’s commitment to climate initiatives. The program invests in projects “that accelerate the implementation of long-duration energy storage solutions to increase the resiliency and reliability of our energy infrastructure and meet the state’s energy and climate goals.” The microgrid also supports regional energy resiliency as it will be able to discharge electricity during emergencies. Schneider Electric, meanwhile, is working with KB Home on the latter’s Energy-Smart Connected Communities program in Menifee, California, which features more than 200 innovative, all-electric homes powered by solar energy and equipped with individual battery storage. Vinayagam said, “These homes will be interconnected through a communal, battery-powered microgrid, fueling the entire neighborhood and ensuring resilience against power outages through a self-sustaining energy ecosystem.” Vinayagam also noted the Citycon development in Finland. “Citycon is Europe’s first energy self-sufficient, sustainable, and carbon-neutral city center,” said Vinayagam. “The goal of the project includes lowering energy consumption and achieving high sustainability through net-zero emissions. Its solar energy and energy storage infrastructure [solar panel array capable of producing 750 kWh of electrical energy and storing 1.5 MW/1.5 MWh of energy] enables the monetization of its generation capability and flexibility. This 1.6 million-square-foot mixed-use facility boasts a 14% reduction in annual energy costs and will provide payback within five years.” Schneider Electric also supports a microgrid at New York’s John F. Kennedy (JFK) International Airport. The system at New Terminal One, or NTO, makes the JFK site “the first resilient airport transit hub in the New York region that can function independently of the power grid, to maintain 100% of airport operations during power disruptions across the 23 gates and more than 177,000 square feet of dining, retail, lounges, and recreational space,” said Vinayagam. A microgrid developed by Scale Microgrids at Gallaudet University in Washington, D.C. (Figure 3), provides an example of how microgrids can be part of a community solar program. Additional solar power capacity from the Gallaudet microgrid, which utilizes solar panels on campus buildings, will be made available to residents of the district through a program that provides electricity from renewable resources to households and small businesses in D.C. [caption id="attachment_220348" align="aligncenter" width="740"]

3. This microgrid, developed by Scale Microgrids, serves Gallaudet University in Washington, D.C. The installation is part of a community solar program that also supports the local neighborhood. Courtesy: Scale Microgrids[/caption] San Diego Gas & Electric in February of this year unveiled four new microgrids that feature “advanced remote operation capabilities and state-of-the-art safety technologies to help enhance grid reliability and bolster resiliency for the surrounding communities,” according to the utility. The four microgrid sites, each including energy storage, support the communities of Clairemont, Tierra Santa, Paradise (Figure 4), and Boulevard. The utility said the microgrids “will help address surging energy demands in the San Diego region, especially during hot summer days and the peak evening hours when solar power generation typically diminishes and there is significant strain on the grid.” [caption id="attachment_220350" align="aligncenter" width="740"]

4. The Paradise microgrid in San Diego, California, has the ability to power Fire Stations 51 and 32, the Southeast Division Police Department, Bell Middle School, and Freese, Boone, and Fulton Elementary Schools. Courtesy: San Diego Gas & Electric[/caption] Caroline Winn, the utility’s CEO, said: “Storage and microgrids are key to helping build a more resilient electric grid that can extend the availability of cleaner energy and help our communities better manage through grid emergencies like the extreme heat experienced in recent summers. These microgrids will actively dispatch clean energy to the grid when needed and help improve energy resiliency for critical facilities like fire stations, schools, and cooling centers in San Diego.”

Energy Storage

The systems in San Diego and elsewhere illustrate how battery energy storage increasingly is being incorporated into microgrid design to support increased power production and more flexible electricity dispatch. “Battery energy storage systems maximize the impact of microgrids. By decoupling production and consumption, storage allows consumers to use energy whenever and wherever it is most needed,” said Vinayagam. “To reduce energy costs, a facility with a microgrid can leverage a BESS to store power from variable renewable energy sources, such as solar or wind, and substitute the stored energy for utility power when utility rates are highest in an attempt to arbitrage.” Vinayagam added, “A BESS can also make a microgrid more resilient. In a utility outage or a temporary drop in energy generated by the microgrid, the BESS can come online almost instantly to support critical loads. Finally, energy storage advances decarbonization initiatives by helping the organization maximize the self-consumption of renewable energy. This also accelerates the ROI [return on investment] from a microgrid.” Redflow, an Australian energy storage company, is supporting a microgrid in Tasmania, Australia. The BESS at that site is a project watched by the Australian Renewable Energy Agency (ARENA), which is backing trial deployments of two different non-lithium battery technologies at microgrids in Western Australia. ARENA in March of this year said the trial is aimed at determining whether sodium-sulfur and zinc-bromine hybrid flow batteries can help integrate rooftop solar PV onto local electricity networks. ARENA is providing financial help to Horizon Power, an energy company owned by the state government of Western Australia, to install the systems at two remote sites (Figure 5) through ARENA’s Regional Microgrids Program. The agency said the trial is a test of two long-duration energy storage, or LDES, technologies. The systems are touted as suitable for applications that require durations of six hours or more. The Australia locations also will help determine viability in extremely hot environments. [caption id="attachment_220351" align="aligncenter" width="740"]

5. This microgrid in Onslow, a remote community in Western Australia, serves customers of Horizon Power. It features an advanced microgrid controller and a distributed energy resources management system from PXiSE, a San Diego, California–based grid management company. Courtesy: Horizon Power[/caption] Redflow projects in the U.S. include a flow battery storage solution at the waste-to-energy Rialto Bioenergy Facility in California. The site provides organic waste recycling and renewable energy generation services to local government authorities and solid waste haulers. Anaergia constructed an onsite microgrid as part of the project to maximize the use of onsite generated power and to limit their peak load from the grid. “Energy storage is very important to the design of today’s microgrids. A lot of microgrids are still based around a single set of generators, but we are seeing a rapidly increasing trend of microgrids with grid-forming energy storage and distributed grid-following PV,” said Siira. “Even in cases where a microgrid is centered around reciprocating generators, energy storage is often being deployed to allow for optimal operation of the generator, to eliminate low-load operation, and to greatly increase the fuel efficiency and lifespan of the generator. This design has been particularly attractive in remote villages, like some in Alaska, for example, where fuel costs are extremely high.” Siira added: “Energy storage is also a critical component of microgrids because it provides a buffer for transients between connection and disconnection, and changing contributions of distributed energy resources. Energy storage systems that are paired with grid-forming inverters can form consistent references for remote electric distribution systems that enhance their reliability. The increasing implementation of energy storage systems and renewable energy sources into the power system will supplement the growth of microgrids, as such systems are optimal for achieving maximum operational efficiency. This trend is already increasing in popularity and is being used among data centers and other critical power industrial facilities.”

Continued Use of Fossil Fuels

Many microgrids have relied on fossil fuels such as diesel or natural gas to provide power to generators. While renewable resources are being utilized in many of today’s designs, thermal generation remains important. “Fossil fuels aren’t going away entirely within microgrids—at least not yet,” said Vinayagam. “The key is finding a balance in the path to net-zero operations. The ultimate goal is net zero, a future powered by clean energy, but reaching it requires a balanced approach. Many existing buildings have diesel generators and integrating them into microgrids makes sense. “Microgrids can also use the existing utility grid’s mix, which often includes fossil fuels,” said Vinayagam. “We’re forging the future of microgrids with innovative solutions that seamlessly integrate renewables, storage, and intelligent management systems. While we remain technology-agnostic, utilizing the most effective tools for current needs—which may include fossil fuels for backup—our focus remains firmly on the future. We’re constantly investing in advancements to propel microgrids toward a cleaner, more sustainable energy landscape.” “There is still a place for fossil fuels in the design of microgrids as it remains to be the most viable form of long-duration energy storage that we have, even though it only allows for one-way conversion,” said Siira. “Despite all the drawbacks, diesel generators remain a staple of microgrids and stand-alone power systems, and likely will for some time. In some places, there has been an increase in the use of propane-fired generators, as opposed to diesel generators. This is mostly for environmental reasons but also due to the fact that propane has an exceptionally long storage life when compared to diesel. Some urban microgrids with easier access to natural gas supplies tie into that for their microgrid generators. Conversely, there are developments being made in the area of alternative fuels such as sustainable or ‘green’ propane, dimethyl ether [commonly called DME], biodiesel, and biogas, for example.” Siira told POWER, “Synchronous rotating machine generators that use fossil fuels will remain a key part of microgrids for some time. This is due to a couple of factors. First, inverter-based distributed energy resources [IBRs] have no inherent rotating inertia and need that propulsion. IBRs also have no significant stored energy; the capacitors and inductors are not used as storage devices. And finally, IBRs do not possess typical dynamic characteristics associated with rotating masses and machine windings, including damping types, that synchronous machines do have.”

Expect Higher Microgrid Adoption

A recent report from Colorado-headquartered Guidehouse Insights looked at the trends that influence microgrid adoption across the U.S. The group in a news release said the report found that “customers in all segments are increasingly investigating microgrids in the face of rising retail electricity rates, persistent grid outages from more and more frequent extreme weather events, and aggressive decarbonization goals.” “As retail electricity rates continue to rise, the frequency and intensity of extreme weather events causing grid outages increases, and decarbonization goals become more aggressive, customers in all segments are investigating microgrids,” said Dan Power, senior research analyst with Guidehouse Insights. “Customer interest in installing microgrids depends on numerous factors linked to their geographic location and the system’s intended use case. Understanding these factors is crucial to facilitating continued market growth.” That growth curve is expected to trend upward as more groups look for technologies to support a reliable and resilient supply of electricity. Said Siira, “More than anything else, microgrids provide enhanced continuity of electric services or power ‘availability’ during major event days for the grid. Microgrids also provide the flexibility to expand capacity and functionality once implemented into the overall system. For example, this could include increasing the integration of renewable energy sources as demand and technology capabilities advance, without having to go through interconnection approval at a site.” There are other considerations, in addition to reliability and resiliency, that will likely support microgrid adoption. “The most important feature of a microgrid isn’t a single benefit, but its ability to deliver multiple wins for the customer,” said Vinayagam. “Reliability is a critical foundation—microgrids keep the lights on during outages and serve the critical loads of the site—but that’s just the beginning. When combined with cost savings and environmental impact, microgrids become even more attractive. Advanced software solutions are the key to unlocking these multiple benefits. By intelligently managing energy use, storage, and generation, microgrids can optimize costs, maximize renewable energy use, and improve overall efficiency.” Itron’s Tumilowicz said, “An often-overlooked feature of microgrids is not only the ability to support customer power continuity in times of grid outages, but also the ability to provide grid services to keep the grid up and running. This can be accomplished in a variety of ways, including: (1) emergency load reduction bulk dispatch via a surgical disconnect of a small number of customers to prevent larger, system-wide outages [that is, feeder-level premise load shed]; and (2) DER dispatch across certain pockets of the grid to support electrification and renewable generation variability before it becomes a problem for the grid to manage via conventional methods [such as cap banks, voltage regulators, bulk generation, etc.].” “The best microgrid solution will consider the specific needs of the customer, location, and external factors,” said Vinayagam. “One thing remains constant, however: the most powerful feature is the ability to deliver a customized package of reliability, cost savings, and environmental responsibility.” Tumilowicz concurred, noting, “Microgrids are increasingly vital in today’s energy sector, enabling utilities to deliver reliable, efficient, and sustainable energy to their communities. By integrating microgrids, utilities can better manage peak loads, integrate and manage DERs with visibility and control, and improve grid resilience against disruptions. Additionally, microgrids can optimize energy usage and improve operational efficiencies, making them a key component in the transition toward a better-connected, more-sustainable energy future. The adoption and integration of microgrids is essential for modern utilities looking to improve reliability and meet increasing demand on the grid and evolving needs of their consumers.” —Darrell Proctor is a senior associate editor for POWER.