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While relatively consistent for close to 100 years, the electric utility grid and the building market it supplies is now forced to change. Users of energy are increasingly also becoming producers and thus &#;prosumers.&#; This backdrop, along with the drive for digital transformation, sustainability and resilience is driving a &#;new energy landscape.&#; Microgrids are a way to optimize this scenario while also optimizing energy costs.
Review these additional responses from Gregg Morasca, VP, Microgrid Content, North America Operations, Schneider Electric, which were answered after the &#;What is the new energy landscape and how does it affect microgrids?&#; webcast Aug. 10, .
Answer: Lithium-ion batteries are the lowest cost option compared to other battery technologies. This is based on upfront cost and the lifetime of the system. The next option for cost effective energy storage is lead acid batteries. Please refer to the list for top nine most cost-effective energy storage options.
Answer: SMRs have the potential to be viable elements of a microgrid in certain circumstances since they are smaller and more flexible and can generate low level of electricity when compared to traditional large scale nuclear reactors. Some factors that make them suitable for integration include reliable baseload power, diverse energy mix, reduced carbon emissions, long operating life, less space and infrastructure requirements. However, some complex challenges revolve around the fact that nuclear power is highly regulated due to safety and security concerns. Making the decision to integrate SMRs would mean seeking compliance with nuclear regulatory requirements which can be time consuming. It is also important to consider that the upfront capital costs of SMRs can be heavy and the financial feasibility of integrating an SMR would depend of different factors such as available funding, project scale and cost-sharing arrangements. Also, it is important to note that that if we integrate SMRs into microgrids then we need proper management of nuclear waste since storage and disposal of nuclear waste requires planning in advance and can pose several challenges.
Answer: Islandable microgrids are designed with what we call an &#;anchor resource&#; so that even when there is a power outage, there is an automated system in place that can isolate from the main grid (ex. Open the site&#;s main circuit breaker) and then turn on a power source that can provide a voltage reference. This anchor resource (source providing a voltage reference) might be a generator or a battery energy storage system (BESS). This type of system is required to submit an interconnection application and clearly define the islanding intent in the application in conjunction with the utility&#;s requirements.
Answer: Contrary to the common belief that high penetration rates of DER degrade power quality and reliability, the experience in Germany has shown improved grid reliability over the past 10 years. According to the German regulatory agency, BnetzA, in , &#;The electricity supply in Germany was again very reliable in &#; the outage time was lower than in the previous year&#; As in the past, the energy transition and the growth in distributed generation have not had any negative effects on the quality of supply.&#; Grid stability is supported through optimization software that leverages automation technologies, including machine learning, artificial intelligence, advanced forecasting and advanced displays. This enables operators to operate their systems for efficiently.
Answer: DERs, including PV systems and BESS, generally do not have the same inherent capability to provide zero sequence fault currents as traditional rotating machine generators. The amount of fault current support that DERs can provide depends on various factors, including their design, control capabilities and the specific requirements of the grid they are connected to. While inverter based DERs might not replicate the same level of zero sequence fault current contribution as traditional rotating generators, they can be engineered to offer some level of fault current support to enhance grid stability.
Answer: The receptiveness of utility companies to grid-tied microgrid approaches can vary depending on many factors such as region, utility company policies, regulatory environment and specific goals and benefits that microgrids offer. There are factors such as the stability and reliability of the grid that can have a large impact. Grid-tied microgrids that can integrate with the main grid and provide support during peak demand or emergencies can be seen as beneficial by utilities. Another factor is renewable energy integration. Grid-tied microgrids with renewable energy sources, such as solar and wind, can help utilities meet renewable energy targets. Utility companies interested in transitioning to cleaner energy sources can view grid-tied microgrids positively. Some potential challenges that lead to their resistance include ensuring that microgrid systems are technically compatible with the utility&#;s existing infrastructure and can operate safely and efficiently in parallel can be a challenge. In addition, meeting grid interconnection standards and requirements set by regulatory bodies and industry organizations can require careful planning and coordination.
Overall, the receptiveness of grid-tied microgrids by utility companies continues to change as the benefits become more apparent and as regulatory frameworks adapt to accommodate these new technologies. It is important to ensure there is communication and allude to the value that grid-tied microgrids can bring to both the utility and the broader energy system.
Answer: There are different designs to a microgrid. For instance, in a grid-connected microgrid it does remain connected to the main power grid but it has the option to operate independently if it is necessary. It is also important to keep in mind that during normal operation of the microgrid it takes from the grid but it also gives back to the grid. A grid-connected microgrid can supply power to the area and potentially reduce the demand on the national grid during peak usage periods. In addition, when the microgrid generates excess power, it can either feed it back to the main grid if the utility finds that it can help alleviate some of the strain or microgrids can be designed such that excess generation is curtailed or stored for later use, which we call non-export. These designs must be taken on a case-by-case basis with the utility.
In addition, when the microgrid generates excess power, it can either feed it back to the main grid if the utility finds that it can help alleviate some of the strain or microgrids can be designed such that excess generation is curtailed or stored for later use, which we call non-export. These designs must be taken on a case-by-case basis with the utility.
Answer: Net metering is a way for facilities to receive financial compensation for the on-site power they produce. If there are multiple distributed energy resources operating at the site, such as solar + BESS, then we consider it a grid-connected microgrid.
Answer: The microgrid assets themselves in conjunction with the appropriate power quality solutions can provide frequency stability and harmonic mitigation. This should be evaluated on a site-by-site basis where power quality issues are prevalent. The loads and sources must be evaluated holistically.
Answer: Yes, this is something that is very specific to the state and utility. As part of a feasibility study, we will investigate those rules and regulations in order to build a microgrid for the customer that is compliant with their local and state regulations.
Answer: Different organizations might use the terms interchangeably. Most often, the minigrid term is used when referencing a fully off grid that no central utility currently serves. It is a good practice to communicate the details clearly to avoid confusion and to ensure that the terminology aligns with industry standards and the understanding of the intended audience.
Answer: A microgrid system should be maintained and tested with regularity as a system. If one DER is underperforming, it may impact the performance of the system. Typical maintenance schedules depend widely on the use case that the DER is performing and the criticality of the site.
Answer: Typical system losses from central power plants through transmission and distribution are generalized between 8 to 15%. By producing power on-site through the microgrid, these system losses are not incurred.
Answer: Fully agreed. Fault analyses and system coordination are key parts to any microgrid design.
Answer: EEC or ECC? We have a microgrid technology called an Energy Control Center (ECC) which brings together electrical distribution with the brains of a microgrid (microgrid controller) into a single tested solution. It is a simplified way to bring together hardware and software, to connect DERs into a facility at low voltage (480V). Schneider Electric does not make Energy Efficiency Controllers
Answer: O&M costs should be projected during system design and take into account the switching and usage of the system components. The microgrid optimization software, &#;EcoStruxure Microgrid Advisor&#; does not provide preventative maintenance predictions natively but another software, EcoStruxure Asset Advisor that Schneider has launched does provide preventative maintenance evaluations.
Answer: We do have experience in WWW segment applications. Because these sites vary significantly in size and complexity, the architecture is often site dependent. The goal is to always maintain the resiliency needed for these critical sites while maximizing the production of the on-site resources during the normal grid connected mode.
Answer: When utility is unavailable, the anchor resource, such as a generator in this instance would come online within the normal time frame (perhaps 10s in some applications). Once the stable voltage is detected, the microgrid controller would enable the PV to parallel to the generator and prioritize power stability and operating conditions of the generator while accepting as much renewable production.
Answer: Using ac power over having a dedicated dc battery system for motorized breaker control power depends on different factors such as maintenance, cost and reliability. Both have their advantages, for ac power, it is more reliable in terms of power availability and does not require charging systems and dedicated batteries. However, there are some issues like voltage fluctuation and interruptions in the local ac supply that can impact breaker operation. On the other hand, a separate dc battery system can provide reliable and independent power source for breaker control. For facilities with critical loads like hospitals and data centers might benefit more from a dc battery system to make there is uninterruptible breaker control. In facilities with less critical loads local ac power may be enough and is also the more cost-effective option.
Answer: An underfrequency load shedding curve/window represents the relationship between the frequency of an electrical power system and the amount of load shedding that needs to be applied to be able to maintain the stability of the grid. This curve is used to make decision regarding shedding non-critical loads in certain cases where the frequency of the system is dropping below an acceptable level.
Answer: The ROI of a microgrid can potentially be higher due to its ability to provide backup power during outages, reduce demand charges and participate in grid services. However, the initial investment and complexity can also be higher. A static PV system&#;s ROI might be driven by factors like electricity savings through net metering and the local cost of electricity. A detailed financial analysis that considers the specific project parameters, energy usage patterns, local energy costs, potential revenue streams and financing options will be the best way to compare. Additionally, technology costs and market conditions can change over time, affecting the economics of both microgrids and static PV systems.
Answer: Equipment that can be used to run critical loads when on battery or generator power include adding in an Energy Control Center, microgrid controller, transfer switches, a load shedding controller, energy management software (EMS), battery energy storage system and a critical load subpanel.
Answer: There are some instances where local utilities have resisted local energy production. It is important to understand the reasons behind them such as economic concerns, regulatory barriers, and disruptions to the utility business model in place. However, while there have been utilities that have resisted, there are also many that have embraced the transition to decentralized energy systems.
Answer: The implementation of EO and inbuilding of microgrid systems goes hand in hand, as the EO talks about achieving 100% carbon pollution-free electricity by , including 50% on a 24/7 basis. In-building microgrid system is the direct solution to the agenda of EO .
Answer: Maintenance depends on the DERs used in the system (maintaining CHP is very different from maintaining a Li-Ion BESS or Solar PV). What is important to understand is the maintenance of each sub system individually and how they impact the system. At a minimum, we recommend an annual islanding check but some facilities such as health care related facilities may require more frequent servicing than that.
Answer: Cost, value and ROI depend on the design considerations and outcomes desired. These factors can be impacted by funding mechanisms used to pay for the project. For example, Microgrids qualify for various federal funding grants and incentives like IRA and IIJA and NEVI Formula Funding. For example, New Clean Electricity Investment Tax Credit (48E) which is part of IRA where you can be eligible for 30 &#; 70% of grant for the project costs. Microgrids are required for maximum uptime for EV Chargers as well, which can be eligible for NEVI Funding, where costs like pre-engineering work, operational costs, labor costs, legal documentation costs, EV software costs, O&M costs are also covered up to 80%.
Answer: The openness of utilities to incorporating BESS and tying them into their grids can vary widely depending on several factors, including regulatory environment, technical capabilities, economic considerations, etc. The energy landscape is dynamic and attitudes toward BESS integration can change over time. Some utilities might be early adopters and pioneers in integrating BESS, while others might take a more cautious approach due to various considerations. To get the most current and accurate information about a specific utility&#;s stance on BESS integration, it is recommended to directly communicate with the utility in question or consult with energy industry experts who are up-to-date with the latest developments. Inverter tolerances depend on frequency and voltage regulation requirements, voltage ride-through and code compliance.
Answer: There are a variety of incentives out there that can help you identify potential funding sources for microgrid projects. First, you need to determine the technical and economic viability of the microgrid project. This can be done with a feasibility assessment that both our microgrid and microgrid consulting services team can perform depending on your scope of work. Funding sources can come from government grants and incentives, utility programs, power purchase agreements, energy service agreements and energy savings performance contracts.
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In recent weeks, two microgrids &#; San Diego Gas & Electric&#;s demonstration project in Borrego Springs, California (recently heralded for keeping the lights on during a transmission line problem) and Konterra&#;s solar-storage project at its Maryland corporate headquarters &#; have made headlines.
But in ownership, scale, design and operation they&#;re very different. Which raises a fundamental question about a word too often thrown about in electricity circles: What, exactly, is a microgrid?
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The electricity grid is evolving, moving away from the traditional centralized grid and toward a more-distributed grid using local sources of generation, resulting in more microgrids. At the same time, islands and remote communities around the world operate grids that are completely separate from any larger grid, and these are also often referred to as microgrids.
In general, microgrids are small power systems that use local generation resources to meet local electricity needs.
However, because different people use the word microgrid to describe different things, it can be difficult to have a clear understanding of what is meant in specific situations. More important than agreeing on a standard definition of a microgrid is having a shared understanding of the specific microgrid in question in a particular situation.
Because the word microgrid can mean many things, it&#;s important to have a clear understanding of exactly what is meant whenever there is a conversation about this important topic.
The examples below help illustrate the range of possible definitions.
One way to learn more about a microgrid is to understand who owns it.
Bloomberg&#;s research group divides microgrids into five ownership categories: commercial or industrial; community or utility; campus or institutional; military; and off-grid or remote.
For example, the Borrego Springs microgrid serves that community and is owned and operated by the local San Diego utility, SDG&E. The U.S. military has been implementing microgrids, both at stationary bases in the U.S. and at forward operating bases overseas.
Along with the question of which type of entity owns the microgrid, it also can be useful to understand if there are multiple owners.
In military microgrids, there is usually just one owner: the military. Other microgrids, however, may have different entities owning various pieces of the system, such as the generation, the storage and the connecting infrastructure.
At the Philadelphia Navy Yard, a 1,200-acre former naval shipyard that has become a modern business campus, several partners, including Penn State and Alstom, have come together to further advance microgrid technologies.
Many microgrids are connected to the larger grid, with an option to disconnect and become an electrical island.
Alternatively, some microgrids may not interact with the larger grid at all, but instead operate as completely separate electricity systems.
Such systems are operating today on many islands and in remote communities around the world. While these are really just smaller versions of the grid, they often are referred to as microgrids.
Another key defining aspect of each microgrid is size.
Size can be expressed in terms of installed generation capacity, peak load, number of people served or amount of land covered.
Some might consider a smart home that includes distributed energy resources, such as solar PV and battery storage, to be a microgrid. Others might suggest that something as small as a home is really more of a nanogrid, or even a picogrid.
Meanwhile, many island systems, such as those in the Caribbean, are considered microgrids &#; even those that have several megawatts (MW) of peak load.
The lines determining what size fits into the pico, nano, micro and macrogrid categories are blurry, so asking about the size can bring clarity to the conversation.
As another distinction, microgrids may be built to serve varying purposes.
In some cases, the main purpose may be to provide emergency backup power to critical loads. On the other hand, some microgrids (such as those on islands and in remote communities) are built to operate normally at all times.
Other microgrids might fall somewhere in between. At the University of California, San Diego, the campus microgrid provides power in parallel with the grid during normal operation, but also can meet most campus loads during a grid outage (such as the 15-hour outage that occurred in ).
Along with its general purpose somewhere on the spectrum between emergency backup and continuous operation, another key question is how much load the microgrid is designed to cover.
Will it cover just the critical loads, or all of the required loads? For example, the microgrid being considered in Hoboken, New Jersey (one of the teams at RMI&#;s recent eLab Accelerator event) would provide critical support in the event of another storm like Hurricane Sandy.
Meanwhile, a microgrid on an island or in a remote community is likely designed to meet all of the loads from residences and businesses.
Given the mix of generation and storage resources included in a microgrid, it may be designed to provide power for a certain amount of time.
Again in the example of islands and remote communities, many microgrids are designed to provide continuous 24/7 power using local generation resources (and possibly some storage).
On the other hand, microgrids built for emergency backup, such as those that power critical substation equipment when the grid goes down, may rely more heavily on storage or have a fixed amount of fuel available for generation resources. This means that they are designed to provide backup power for a fixed period (say 48 hours) during an emergency, just until the main grid can be restored.
Microgrids also can differ in their physical infrastructure. They may be built using some of the actual grid infrastructure that already exists. Alternatively, they may be physically separate, and built in parallel to the grid.
The microgrid planned in Hoboken, for example, will be built with all new infrastructure in parallel to the grid to increase the city&#;s resilience in an emergency event that disables the main electricity grid.
Different microgrids may have different degrees of intelligence, both in how they operate and in how they interact with the larger grid.
Some microgrids require a manual operation to disconnect from (or reconnect to) the rest of the grid. Others are able to do this dynamically, using smart controls that ensure the microgrid frequency and voltage match the rest of the grid.
In addition, smart controls may be included within the internal operation of the microgrid. Peter Lillienthal, CEO of HOMER Energy, explains how controls can differentiate microgrids, as there may be controls for load management and demand response, as well as for handling the parallel operation of multiple generation resources.
One interesting example is the system on King Island, Tasmania, a utility-owned microgrid without a connection to any outside grid. In this system, wind, solar and diesel generators are combined with a battery, flywheel and dynamic resistor to provide a peak load of 2.5 MW electricity to 2,000 residents.
King Island&#;s microgrid includes smart controls with a centralized energy management system to optimize the use of the renewable and storage resources. It also includes residential smart meters, which allow the system operators to monitor and control interruptible loads (water heaters or heating and cooling systems) in participating homes.
Along with various ways to add technical smarts to a microgrid, there are also options for dynamically exchanging services, value and money across the point of interconnection between a microgrid and the main grid. Such microgrids are called transactive.
For example, the microgrid at the U.S. Food and Drug Administration&#;s White Oak facility operates in parallel with the grid. It also can operate as an electrical island during a grid disturbance or blackout. In addition, the microgrid participates in demand response events as needed by the local utility and has the ability to make power-purchasing decisions.
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